Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 updates from Will Deacon: "A sizeable pile of arm64 updates for 5.8. Summary below, but the big two features are support for Branch Target Identification and Clang's Shadow Call stack. The latter is currently arm64-only, but the high-level parts are all in core code so it could easily be adopted by other architectures pending toolchain support Branch Target Identification (BTI): - Support for ARMv8.5-BTI in both user- and kernel-space. This allows branch targets to limit the types of branch from which they can be called and additionally prevents branching to arbitrary code, although kernel support requires a very recent toolchain. - Function annotation via SYM_FUNC_START() so that assembly functions are wrapped with the relevant "landing pad" instructions. - BPF and vDSO updates to use the new instructions. - Addition of a new HWCAP and exposure of BTI capability to userspace via ID register emulation, along with ELF loader support for the BTI feature in .note.gnu.property. - Non-critical fixes to CFI unwind annotations in the sigreturn trampoline. Shadow Call Stack (SCS): - Support for Clang's Shadow Call Stack feature, which reserves platform register x18 to point at a separate stack for each task that holds only return addresses. This protects function return control flow from buffer overruns on the main stack. - Save/restore of x18 across problematic boundaries (user-mode, hypervisor, EFI, suspend, etc). - Core support for SCS, should other architectures want to use it too. - SCS overflow checking on context-switch as part of the existing stack limit check if CONFIG_SCHED_STACK_END_CHECK=y. CPU feature detection: - Removed numerous "SANITY CHECK" errors when running on a system with mismatched AArch32 support at EL1. This is primarily a concern for KVM, which disabled support for 32-bit guests on such a system. - Addition of new ID registers and fields as the architecture has been extended. Perf and PMU drivers: - Minor fixes and cleanups to system PMU drivers. Hardware errata: - Unify KVM workarounds for VHE and nVHE configurations. - Sort vendor errata entries in Kconfig. Secure Monitor Call Calling Convention (SMCCC): - Update to the latest specification from Arm (v1.2). - Allow PSCI code to query the SMCCC version. Software Delegated Exception Interface (SDEI): - Unexport a bunch of unused symbols. - Minor fixes to handling of firmware data. Pointer authentication: - Add support for dumping the kernel PAC mask in vmcoreinfo so that the stack can be unwound by tools such as kdump. - Simplification of key initialisation during CPU bringup. BPF backend: - Improve immediate generation for logical and add/sub instructions. vDSO: - Minor fixes to the linker flags for consistency with other architectures and support for LLVM's unwinder. - Clean up logic to initialise and map the vDSO into userspace. ACPI: - Work around for an ambiguity in the IORT specification relating to the "num_ids" field. - Support _DMA method for all named components rather than only PCIe root complexes. - Minor other IORT-related fixes. Miscellaneous: - Initialise debug traps early for KGDB and fix KDB cacheflushing deadlock. - Minor tweaks to early boot state (documentation update, set TEXT_OFFSET to 0x0, increase alignment of PE/COFF sections). - Refactoring and cleanup" * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (148 commits) KVM: arm64: Move __load_guest_stage2 to kvm_mmu.h KVM: arm64: Check advertised Stage-2 page size capability arm64/cpufeature: Add get_arm64_ftr_reg_nowarn() ACPI/IORT: Remove the unused __get_pci_rid() arm64/cpuinfo: Add ID_MMFR4_EL1 into the cpuinfo_arm64 context arm64/cpufeature: Add remaining feature bits in ID_AA64PFR1 register arm64/cpufeature: Add remaining feature bits in ID_AA64PFR0 register arm64/cpufeature: Add remaining feature bits in ID_AA64ISAR0 register arm64/cpufeature: Add remaining feature bits in ID_MMFR4 register arm64/cpufeature: Add remaining feature bits in ID_PFR0 register arm64/cpufeature: Introduce ID_MMFR5 CPU register arm64/cpufeature: Introduce ID_DFR1 CPU register arm64/cpufeature: Introduce ID_PFR2 CPU register arm64/cpufeature: Make doublelock a signed feature in ID_AA64DFR0 arm64/cpufeature: Drop TraceFilt feature exposure from ID_DFR0 register arm64/cpufeature: Add explicit ftr_id_isar0[] for ID_ISAR0 register arm64: mm: Add asid_gen_match() helper firmware: smccc: Fix missing prototype warning for arm_smccc_version_init arm64: vdso: Fix CFI directives in sigreturn trampoline arm64: vdso: Don't prefix sigreturn trampoline with a BTI C instruction ...
author: Linus Torvalds <torvalds@linux-foundation.org> 2020-06-01 15:18:27 -0700
committer: Linus Torvalds <torvalds@linux-foundation.org> 2020-06-01 15:18:27 -0700
commit: 533b220f7be4e461a5222a223d169b42856741ef (patch)
tree: 3684fae5a676b31a4a75e275a0ee5519f0d3c6d9 /arch/arm64/kernel
parent: 3ee3723b40d55f473b8c82c60ed0e67f1f9ec6b9 (diff)
parent: 082af5ec5080b028f7d0846a6c27cbb87f288205 (diff)
download: lwn-533b220f7be4e461a5222a223d169b42856741ef.tar.gz
lwn-533b220f7be4e461a5222a223d169b42856741ef.zip
43 files changed, 949 insertions, 442 deletions
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 4e5b8ee31442..151f28521f1e 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -63,6 +63,7 @@ obj-$(CONFIG_CRASH_CORE)		+= crash_core.o
 obj-$(CONFIG_ARM_SDE_INTERFACE)		+= sdei.o
 obj-$(CONFIG_ARM64_SSBD)		+= ssbd.o
 obj-$(CONFIG_ARM64_PTR_AUTH)		+= pointer_auth.o
+obj-$(CONFIG_SHADOW_CALL_STACK)		+= scs.o
 
 obj-y					+= vdso/ probes/
 obj-$(CONFIG_COMPAT_VDSO)		+= vdso32/
diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
index 9981a0a5a87f..3539d7092612 100644
--- a/arch/arm64/kernel/asm-offsets.c
+++ b/arch/arm64/kernel/asm-offsets.c
@@ -34,6 +34,10 @@ int main(void)
 #ifdef CONFIG_ARM64_SW_TTBR0_PAN
   DEFINE(TSK_TI_TTBR0,		offsetof(struct task_struct, thread_info.ttbr0));
 #endif
+#ifdef CONFIG_SHADOW_CALL_STACK
+  DEFINE(TSK_TI_SCS_BASE,	offsetof(struct task_struct, thread_info.scs_base));
+  DEFINE(TSK_TI_SCS_SP,		offsetof(struct task_struct, thread_info.scs_sp));
+#endif
   DEFINE(TSK_STACK,		offsetof(struct task_struct, stack));
 #ifdef CONFIG_STACKPROTECTOR
   DEFINE(TSK_STACK_CANARY,	offsetof(struct task_struct, stack_canary));
@@ -92,9 +96,6 @@ int main(void)
   BLANK();
   DEFINE(CPU_BOOT_STACK,	offsetof(struct secondary_data, stack));
   DEFINE(CPU_BOOT_TASK,		offsetof(struct secondary_data, task));
-#ifdef CONFIG_ARM64_PTR_AUTH
-  DEFINE(CPU_BOOT_PTRAUTH_KEY,	offsetof(struct secondary_data, ptrauth_key));
-#endif
   BLANK();
 #ifdef CONFIG_KVM_ARM_HOST
   DEFINE(VCPU_CONTEXT,		offsetof(struct kvm_vcpu, arch.ctxt));
diff --git a/arch/arm64/kernel/cpu-reset.S b/arch/arm64/kernel/cpu-reset.S
index 38087b4c0432..4a18055b2ff9 100644
--- a/arch/arm64/kernel/cpu-reset.S
+++ b/arch/arm64/kernel/cpu-reset.S
@@ -29,7 +29,7 @@
  * branch to what would be the reset vector. It must be executed with the
  * flat identity mapping.
  */
-ENTRY(__cpu_soft_restart)
+SYM_CODE_START(__cpu_soft_restart)
 	/* Clear sctlr_el1 flags. */
 	mrs	x12, sctlr_el1
 	mov_q	x13, SCTLR_ELx_FLAGS
@@ -47,6 +47,6 @@ ENTRY(__cpu_soft_restart)
 	mov	x1, x3				// arg1
 	mov	x2, x4				// arg2
 	br	x8
-ENDPROC(__cpu_soft_restart)
+SYM_CODE_END(__cpu_soft_restart)
 
 .popsection
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index df56d2295d16..b0ce6bf14f6a 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -635,7 +635,7 @@ has_neoverse_n1_erratum_1542419(const struct arm64_cpu_capabilities *entry,
 	return is_midr_in_range(midr, &range) && has_dic;
 }
 
-#if defined(CONFIG_HARDEN_EL2_VECTORS) || defined(CONFIG_ARM64_ERRATUM_1319367)
+#if defined(CONFIG_HARDEN_EL2_VECTORS)
 
 static const struct midr_range ca57_a72[] = {
 	MIDR_ALL_VERSIONS(MIDR_CORTEX_A57),
@@ -757,12 +757,16 @@ static const struct arm64_cpu_capabilities erratum_843419_list[] = {
 };
 #endif
 
-#ifdef CONFIG_ARM64_WORKAROUND_SPECULATIVE_AT_VHE
-static const struct midr_range erratum_speculative_at_vhe_list[] = {
+#ifdef CONFIG_ARM64_WORKAROUND_SPECULATIVE_AT
+static const struct midr_range erratum_speculative_at_list[] = {
 #ifdef CONFIG_ARM64_ERRATUM_1165522
 	/* Cortex A76 r0p0 to r2p0 */
 	MIDR_RANGE(MIDR_CORTEX_A76, 0, 0, 2, 0),
 #endif
+#ifdef CONFIG_ARM64_ERRATUM_1319367
+	MIDR_ALL_VERSIONS(MIDR_CORTEX_A57),
+	MIDR_ALL_VERSIONS(MIDR_CORTEX_A72),
+#endif
 #ifdef CONFIG_ARM64_ERRATUM_1530923
 	/* Cortex A55 r0p0 to r2p0 */
 	MIDR_RANGE(MIDR_CORTEX_A55, 0, 0, 2, 0),
@@ -774,7 +778,7 @@ static const struct midr_range erratum_speculative_at_vhe_list[] = {
 const struct arm64_cpu_capabilities arm64_errata[] = {
 #ifdef CONFIG_ARM64_WORKAROUND_CLEAN_CACHE
 	{
-		.desc = "ARM errata 826319, 827319, 824069, 819472",
+		.desc = "ARM errata 826319, 827319, 824069, or 819472",
 		.capability = ARM64_WORKAROUND_CLEAN_CACHE,
 		ERRATA_MIDR_RANGE_LIST(workaround_clean_cache),
 		.cpu_enable = cpu_enable_cache_maint_trap,
@@ -856,7 +860,7 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
 #endif
 #ifdef CONFIG_ARM64_WORKAROUND_REPEAT_TLBI
 	{
-		.desc = "Qualcomm erratum 1009, ARM erratum 1286807",
+		.desc = "Qualcomm erratum 1009, or ARM erratum 1286807",
 		.capability = ARM64_WORKAROUND_REPEAT_TLBI,
 		.type = ARM64_CPUCAP_LOCAL_CPU_ERRATUM,
 		.matches = cpucap_multi_entry_cap_matches,
@@ -897,11 +901,11 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
 		ERRATA_MIDR_RANGE_LIST(erratum_1418040_list),
 	},
 #endif
-#ifdef CONFIG_ARM64_WORKAROUND_SPECULATIVE_AT_VHE
+#ifdef CONFIG_ARM64_WORKAROUND_SPECULATIVE_AT
 	{
-		.desc = "ARM errata 1165522, 1530923",
-		.capability = ARM64_WORKAROUND_SPECULATIVE_AT_VHE,
-		ERRATA_MIDR_RANGE_LIST(erratum_speculative_at_vhe_list),
+		.desc = "ARM errata 1165522, 1319367, or 1530923",
+		.capability = ARM64_WORKAROUND_SPECULATIVE_AT,
+		ERRATA_MIDR_RANGE_LIST(erratum_speculative_at_list),
 	},
 #endif
 #ifdef CONFIG_ARM64_ERRATUM_1463225
@@ -935,13 +939,6 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
 		.cpu_enable = cpu_enable_trap_ctr_access,
 	},
 #endif
-#ifdef CONFIG_ARM64_ERRATUM_1319367
-	{
-		.desc = "ARM erratum 1319367",
-		.capability = ARM64_WORKAROUND_SPECULATIVE_AT_NVHE,
-		ERRATA_MIDR_RANGE_LIST(ca57_a72),
-	},
-#endif
 	{
 	}
 };
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 9fac745aa7bb..4ae41670c2e6 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -3,6 +3,61 @@
  * Contains CPU feature definitions
  *
  * Copyright (C) 2015 ARM Ltd.
+ *
+ * A note for the weary kernel hacker: the code here is confusing and hard to
+ * follow! That's partly because it's solving a nasty problem, but also because
+ * there's a little bit of over-abstraction that tends to obscure what's going
+ * on behind a maze of helper functions and macros.
+ *
+ * The basic problem is that hardware folks have started gluing together CPUs
+ * with distinct architectural features; in some cases even creating SoCs where
+ * user-visible instructions are available only on a subset of the available
+ * cores. We try to address this by snapshotting the feature registers of the
+ * boot CPU and comparing these with the feature registers of each secondary
+ * CPU when bringing them up. If there is a mismatch, then we update the
+ * snapshot state to indicate the lowest-common denominator of the feature,
+ * known as the "safe" value. This snapshot state can be queried to view the
+ * "sanitised" value of a feature register.
+ *
+ * The sanitised register values are used to decide which capabilities we
+ * have in the system. These may be in the form of traditional "hwcaps"
+ * advertised to userspace or internal "cpucaps" which are used to configure
+ * things like alternative patching and static keys. While a feature mismatch
+ * may result in a TAINT_CPU_OUT_OF_SPEC kernel taint, a capability mismatch
+ * may prevent a CPU from being onlined at all.
+ *
+ * Some implementation details worth remembering:
+ *
+ * - Mismatched features are *always* sanitised to a "safe" value, which
+ *   usually indicates that the feature is not supported.
+ *
+ * - A mismatched feature marked with FTR_STRICT will cause a "SANITY CHECK"
+ *   warning when onlining an offending CPU and the kernel will be tainted
+ *   with TAINT_CPU_OUT_OF_SPEC.
+ *
+ * - Features marked as FTR_VISIBLE have their sanitised value visible to
+ *   userspace. FTR_VISIBLE features in registers that are only visible
+ *   to EL0 by trapping *must* have a corresponding HWCAP so that late
+ *   onlining of CPUs cannot lead to features disappearing at runtime.
+ *
+ * - A "feature" is typically a 4-bit register field. A "capability" is the
+ *   high-level description derived from the sanitised field value.
+ *
+ * - Read the Arm ARM (DDI 0487F.a) section D13.1.3 ("Principles of the ID
+ *   scheme for fields in ID registers") to understand when feature fields
+ *   may be signed or unsigned (FTR_SIGNED and FTR_UNSIGNED accordingly).
+ *
+ * - KVM exposes its own view of the feature registers to guest operating
+ *   systems regardless of FTR_VISIBLE. This is typically driven from the
+ *   sanitised register values to allow virtual CPUs to be migrated between
+ *   arbitrary physical CPUs, but some features not present on the host are
+ *   also advertised and emulated. Look at sys_reg_descs[] for the gory
+ *   details.
+ *
+ * - If the arm64_ftr_bits[] for a register has a missing field, then this
+ *   field is treated as STRICT RES0, including for read_sanitised_ftr_reg().
+ *   This is stronger than FTR_HIDDEN and can be used to hide features from
+ *   KVM guests.
  */
 
 #define pr_fmt(fmt) "CPU features: " fmt
@@ -124,6 +179,7 @@ static bool __system_matches_cap(unsigned int n);
  */
 static const struct arm64_ftr_bits ftr_id_aa64isar0[] = {
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_RNDR_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_TLB_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_TS_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_FHM_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_DP_SHIFT, 4, 0),
@@ -166,22 +222,27 @@ static const struct arm64_ftr_bits ftr_id_aa64pfr0[] = {
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_CSV2_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_DIT_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_AMU_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_MPAM_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_SEL2_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SVE),
 				   FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_SVE_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_RAS_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_GIC_SHIFT, 4, 0),
 	S_ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_ASIMD_SHIFT, 4, ID_AA64PFR0_ASIMD_NI),
 	S_ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_FP_SHIFT, 4, ID_AA64PFR0_FP_NI),
-	/* Linux doesn't care about the EL3 */
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL3_SHIFT, 4, 0),
-	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL2_SHIFT, 4, 0),
-	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL1_SHIFT, 4, ID_AA64PFR0_EL1_64BIT_ONLY),
-	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL0_SHIFT, 4, ID_AA64PFR0_EL0_64BIT_ONLY),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL2_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL1_SHIFT, 4, ID_AA64PFR0_EL1_64BIT_ONLY),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL0_SHIFT, 4, ID_AA64PFR0_EL0_64BIT_ONLY),
 	ARM64_FTR_END,
 };
 
 static const struct arm64_ftr_bits ftr_id_aa64pfr1[] = {
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR1_MPAMFRAC_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR1_RASFRAC_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR1_SSBS_SHIFT, 4, ID_AA64PFR1_SSBS_PSTATE_NI),
+	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_BTI),
+				    FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR1_BT_SHIFT, 4, 0),
 	ARM64_FTR_END,
 };
 
@@ -209,6 +270,24 @@ static const struct arm64_ftr_bits ftr_id_aa64zfr0[] = {
 
 static const struct arm64_ftr_bits ftr_id_aa64mmfr0[] = {
 	/*
+	 * Page size not being supported at Stage-2 is not fatal. You
+	 * just give up KVM if PAGE_SIZE isn't supported there. Go fix
+	 * your favourite nesting hypervisor.
+	 *
+	 * There is a small corner case where the hypervisor explicitly
+	 * advertises a given granule size at Stage-2 (value 2) on some
+	 * vCPUs, and uses the fallback to Stage-1 (value 0) for other
+	 * vCPUs. Although this is not forbidden by the architecture, it
+	 * indicates that the hypervisor is being silly (or buggy).
+	 *
+	 * We make no effort to cope with this and pretend that if these
+	 * fields are inconsistent across vCPUs, then it isn't worth
+	 * trying to bring KVM up.
+	 */
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_EXACT, ID_AA64MMFR0_TGRAN4_2_SHIFT, 4, 1),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_EXACT, ID_AA64MMFR0_TGRAN64_2_SHIFT, 4, 1),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_EXACT, ID_AA64MMFR0_TGRAN16_2_SHIFT, 4, 1),
+	/*
 	 * We already refuse to boot CPUs that don't support our configured
 	 * page size, so we can only detect mismatches for a page size other
 	 * than the one we're currently using. Unfortunately, SoCs like this
@@ -247,7 +326,7 @@ static const struct arm64_ftr_bits ftr_id_aa64mmfr2[] = {
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_FWB_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_AT_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_LVA_SHIFT, 4, 0),
-	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_IESB_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_IESB_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_LSM_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_UAO_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_CNP_SHIFT, 4, 0),
@@ -289,7 +368,7 @@ static const struct arm64_ftr_bits ftr_id_mmfr0[] = {
 };
 
 static const struct arm64_ftr_bits ftr_id_aa64dfr0[] = {
-	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_EXACT, 36, 28, 0),
+	S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 36, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64DFR0_PMSVER_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64DFR0_CTX_CMPS_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64DFR0_WRPS_SHIFT, 4, 0),
@@ -316,6 +395,16 @@ static const struct arm64_ftr_bits ftr_dczid[] = {
 	ARM64_FTR_END,
 };
 
+static const struct arm64_ftr_bits ftr_id_isar0[] = {
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR0_DIVIDE_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR0_DEBUG_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR0_COPROC_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR0_CMPBRANCH_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR0_BITFIELD_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR0_BITCOUNT_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR0_SWAP_SHIFT, 4, 0),
+	ARM64_FTR_END,
+};
 
 static const struct arm64_ftr_bits ftr_id_isar5[] = {
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_RDM_SHIFT, 4, 0),
@@ -328,7 +417,37 @@ static const struct arm64_ftr_bits ftr_id_isar5[] = {
 };
 
 static const struct arm64_ftr_bits ftr_id_mmfr4[] = {
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_MMFR4_EVT_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_MMFR4_CCIDX_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_MMFR4_LSM_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_MMFR4_HPDS_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_MMFR4_CNP_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_MMFR4_XNX_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 4, 4, 0),	/* ac2 */
+	/*
+	 * SpecSEI = 1 indicates that the PE might generate an SError on an
+	 * external abort on speculative read. It is safe to assume that an
+	 * SError might be generated than it will not be. Hence it has been
+	 * classified as FTR_HIGHER_SAFE.
+	 */
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_HIGHER_SAFE, ID_MMFR4_SPECSEI_SHIFT, 4, 0),
+	ARM64_FTR_END,
+};
+
+static const struct arm64_ftr_bits ftr_id_isar4[] = {
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR4_SWP_FRAC_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR4_PSR_M_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR4_SYNCH_PRIM_FRAC_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR4_BARRIER_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR4_SMC_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR4_WRITEBACK_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR4_WITHSHIFTS_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR4_UNPRIV_SHIFT, 4, 0),
+	ARM64_FTR_END,
+};
+
+static const struct arm64_ftr_bits ftr_id_mmfr5[] = {
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_MMFR5_ETS_SHIFT, 4, 0),
 	ARM64_FTR_END,
 };
 
@@ -344,6 +463,8 @@ static const struct arm64_ftr_bits ftr_id_isar6[] = {
 };
 
 static const struct arm64_ftr_bits ftr_id_pfr0[] = {
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_PFR0_DIT_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_PFR0_CSV2_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 12, 4, 0),		/* State3 */
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 8, 4, 0),		/* State2 */
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 4, 4, 0),		/* State1 */
@@ -351,8 +472,26 @@ static const struct arm64_ftr_bits ftr_id_pfr0[] = {
 	ARM64_FTR_END,
 };
 
+static const struct arm64_ftr_bits ftr_id_pfr1[] = {
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_PFR1_GIC_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_PFR1_VIRT_FRAC_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_PFR1_SEC_FRAC_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_PFR1_GENTIMER_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_PFR1_VIRTUALIZATION_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_PFR1_MPROGMOD_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_PFR1_SECURITY_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_PFR1_PROGMOD_SHIFT, 4, 0),
+	ARM64_FTR_END,
+};
+
+static const struct arm64_ftr_bits ftr_id_pfr2[] = {
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_PFR2_SSBS_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_PFR2_CSV3_SHIFT, 4, 0),
+	ARM64_FTR_END,
+};
+
 static const struct arm64_ftr_bits ftr_id_dfr0[] = {
-	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 28, 4, 0),
+	/* [31:28] TraceFilt */
 	S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 24, 4, 0xf),	/* PerfMon */
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 20, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 16, 4, 0),
@@ -363,6 +502,11 @@ static const struct arm64_ftr_bits ftr_id_dfr0[] = {
 	ARM64_FTR_END,
 };
 
+static const struct arm64_ftr_bits ftr_id_dfr1[] = {
+	S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_DFR1_MTPMU_SHIFT, 4, 0),
+	ARM64_FTR_END,
+};
+
 static const struct arm64_ftr_bits ftr_zcr[] = {
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE,
 		ZCR_ELx_LEN_SHIFT, ZCR_ELx_LEN_SIZE, 0),	/* LEN */
@@ -373,7 +517,7 @@ static const struct arm64_ftr_bits ftr_zcr[] = {
  * Common ftr bits for a 32bit register with all hidden, strict
  * attributes, with 4bit feature fields and a default safe value of
  * 0. Covers the following 32bit registers:
- * id_isar[0-4], id_mmfr[1-3], id_pfr1, mvfr[0-1]
+ * id_isar[1-4], id_mmfr[1-3], id_pfr1, mvfr[0-1]
  */
 static const struct arm64_ftr_bits ftr_generic_32bits[] = {
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 28, 4, 0),
@@ -411,7 +555,7 @@ static const struct __ftr_reg_entry {
 
 	/* Op1 = 0, CRn = 0, CRm = 1 */
 	ARM64_FTR_REG(SYS_ID_PFR0_EL1, ftr_id_pfr0),
-	ARM64_FTR_REG(SYS_ID_PFR1_EL1, ftr_generic_32bits),
+	ARM64_FTR_REG(SYS_ID_PFR1_EL1, ftr_id_pfr1),
 	ARM64_FTR_REG(SYS_ID_DFR0_EL1, ftr_id_dfr0),
 	ARM64_FTR_REG(SYS_ID_MMFR0_EL1, ftr_id_mmfr0),
 	ARM64_FTR_REG(SYS_ID_MMFR1_EL1, ftr_generic_32bits),
@@ -419,11 +563,11 @@ static const struct __ftr_reg_entry {
 	ARM64_FTR_REG(SYS_ID_MMFR3_EL1, ftr_generic_32bits),
 
 	/* Op1 = 0, CRn = 0, CRm = 2 */
-	ARM64_FTR_REG(SYS_ID_ISAR0_EL1, ftr_generic_32bits),
+	ARM64_FTR_REG(SYS_ID_ISAR0_EL1, ftr_id_isar0),
 	ARM64_FTR_REG(SYS_ID_ISAR1_EL1, ftr_generic_32bits),
 	ARM64_FTR_REG(SYS_ID_ISAR2_EL1, ftr_generic_32bits),
 	ARM64_FTR_REG(SYS_ID_ISAR3_EL1, ftr_generic_32bits),
-	ARM64_FTR_REG(SYS_ID_ISAR4_EL1, ftr_generic_32bits),
+	ARM64_FTR_REG(SYS_ID_ISAR4_EL1, ftr_id_isar4),
 	ARM64_FTR_REG(SYS_ID_ISAR5_EL1, ftr_id_isar5),
 	ARM64_FTR_REG(SYS_ID_MMFR4_EL1, ftr_id_mmfr4),
 	ARM64_FTR_REG(SYS_ID_ISAR6_EL1, ftr_id_isar6),
@@ -432,6 +576,9 @@ static const struct __ftr_reg_entry {
 	ARM64_FTR_REG(SYS_MVFR0_EL1, ftr_generic_32bits),
 	ARM64_FTR_REG(SYS_MVFR1_EL1, ftr_generic_32bits),
 	ARM64_FTR_REG(SYS_MVFR2_EL1, ftr_mvfr2),
+	ARM64_FTR_REG(SYS_ID_PFR2_EL1, ftr_id_pfr2),
+	ARM64_FTR_REG(SYS_ID_DFR1_EL1, ftr_id_dfr1),
+	ARM64_FTR_REG(SYS_ID_MMFR5_EL1, ftr_id_mmfr5),
 
 	/* Op1 = 0, CRn = 0, CRm = 4 */
 	ARM64_FTR_REG(SYS_ID_AA64PFR0_EL1, ftr_id_aa64pfr0),
@@ -468,16 +615,16 @@ static int search_cmp_ftr_reg(const void *id, const void *regp)
 }
 
 /*
- * get_arm64_ftr_reg - Lookup a feature register entry using its
- * sys_reg() encoding. With the array arm64_ftr_regs sorted in the
- * ascending order of sys_id , we use binary search to find a matching
+ * get_arm64_ftr_reg_nowarn - Looks up a feature register entry using
+ * its sys_reg() encoding. With the array arm64_ftr_regs sorted in the
+ * ascending order of sys_id, we use binary search to find a matching
  * entry.
  *
  * returns - Upon success,  matching ftr_reg entry for id.
  *         - NULL on failure. It is upto the caller to decide
  *	     the impact of a failure.
  */
-static struct arm64_ftr_reg *get_arm64_ftr_reg(u32 sys_id)
+static struct arm64_ftr_reg *get_arm64_ftr_reg_nowarn(u32 sys_id)
 {
 	const struct __ftr_reg_entry *ret;
 
@@ -491,6 +638,27 @@ static struct arm64_ftr_reg *get_arm64_ftr_reg(u32 sys_id)
 	return NULL;
 }
 
+/*
+ * get_arm64_ftr_reg - Looks up a feature register entry using
+ * its sys_reg() encoding. This calls get_arm64_ftr_reg_nowarn().
+ *
+ * returns - Upon success,  matching ftr_reg entry for id.
+ *         - NULL on failure but with an WARN_ON().
+ */
+static struct arm64_ftr_reg *get_arm64_ftr_reg(u32 sys_id)
+{
+	struct arm64_ftr_reg *reg;
+
+	reg = get_arm64_ftr_reg_nowarn(sys_id);
+
+	/*
+	 * Requesting a non-existent register search is an error. Warn
+	 * and let the caller handle it.
+	 */
+	WARN_ON(!reg);
+	return reg;
+}
+
 static u64 arm64_ftr_set_value(const struct arm64_ftr_bits *ftrp, s64 reg,
 			       s64 ftr_val)
 {
@@ -552,7 +720,8 @@ static void __init init_cpu_ftr_reg(u32 sys_reg, u64 new)
 	const struct arm64_ftr_bits *ftrp;
 	struct arm64_ftr_reg *reg = get_arm64_ftr_reg(sys_reg);
 
-	BUG_ON(!reg);
+	if (!reg)
+		return;
 
 	for (ftrp = reg->ftr_bits; ftrp->width; ftrp++) {
 		u64 ftr_mask = arm64_ftr_mask(ftrp);
@@ -625,6 +794,7 @@ void __init init_cpu_features(struct cpuinfo_arm64 *info)
 
 	if (id_aa64pfr0_32bit_el0(info->reg_id_aa64pfr0)) {
 		init_cpu_ftr_reg(SYS_ID_DFR0_EL1, info->reg_id_dfr0);
+		init_cpu_ftr_reg(SYS_ID_DFR1_EL1, info->reg_id_dfr1);
 		init_cpu_ftr_reg(SYS_ID_ISAR0_EL1, info->reg_id_isar0);
 		init_cpu_ftr_reg(SYS_ID_ISAR1_EL1, info->reg_id_isar1);
 		init_cpu_ftr_reg(SYS_ID_ISAR2_EL1, info->reg_id_isar2);
@@ -636,8 +806,11 @@ void __init init_cpu_features(struct cpuinfo_arm64 *info)
 		init_cpu_ftr_reg(SYS_ID_MMFR1_EL1, info->reg_id_mmfr1);
 		init_cpu_ftr_reg(SYS_ID_MMFR2_EL1, info->reg_id_mmfr2);
 		init_cpu_ftr_reg(SYS_ID_MMFR3_EL1, info->reg_id_mmfr3);
+		init_cpu_ftr_reg(SYS_ID_MMFR4_EL1, info->reg_id_mmfr4);
+		init_cpu_ftr_reg(SYS_ID_MMFR5_EL1, info->reg_id_mmfr5);
 		init_cpu_ftr_reg(SYS_ID_PFR0_EL1, info->reg_id_pfr0);
 		init_cpu_ftr_reg(SYS_ID_PFR1_EL1, info->reg_id_pfr1);
+		init_cpu_ftr_reg(SYS_ID_PFR2_EL1, info->reg_id_pfr2);
 		init_cpu_ftr_reg(SYS_MVFR0_EL1, info->reg_mvfr0);
 		init_cpu_ftr_reg(SYS_MVFR1_EL1, info->reg_mvfr1);
 		init_cpu_ftr_reg(SYS_MVFR2_EL1, info->reg_mvfr2);
@@ -682,7 +855,9 @@ static int check_update_ftr_reg(u32 sys_id, int cpu, u64 val, u64 boot)
 {
 	struct arm64_ftr_reg *regp = get_arm64_ftr_reg(sys_id);
 
-	BUG_ON(!regp);
+	if (!regp)
+		return 0;
+
 	update_cpu_ftr_reg(regp, val);
 	if ((boot & regp->strict_mask) == (val & regp->strict_mask))
 		return 0;
@@ -691,6 +866,104 @@ static int check_update_ftr_reg(u32 sys_id, int cpu, u64 val, u64 boot)
 	return 1;
 }
 
+static void relax_cpu_ftr_reg(u32 sys_id, int field)
+{
+	const struct arm64_ftr_bits *ftrp;
+	struct arm64_ftr_reg *regp = get_arm64_ftr_reg(sys_id);
+
+	if (!regp)
+		return;
+
+	for (ftrp = regp->ftr_bits; ftrp->width; ftrp++) {
+		if (ftrp->shift == field) {
+			regp->strict_mask &= ~arm64_ftr_mask(ftrp);
+			break;
+		}
+	}
+
+	/* Bogus field? */
+	WARN_ON(!ftrp->width);
+}
+
+static int update_32bit_cpu_features(int cpu, struct cpuinfo_arm64 *info,
+				     struct cpuinfo_arm64 *boot)
+{
+	int taint = 0;
+	u64 pfr0 = read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1);
+
+	/*
+	 * If we don't have AArch32 at all then skip the checks entirely
+	 * as the register values may be UNKNOWN and we're not going to be
+	 * using them for anything.
+	 */
+	if (!id_aa64pfr0_32bit_el0(pfr0))
+		return taint;
+
+	/*
+	 * If we don't have AArch32 at EL1, then relax the strictness of
+	 * EL1-dependent register fields to avoid spurious sanity check fails.
+	 */
+	if (!id_aa64pfr0_32bit_el1(pfr0)) {
+		relax_cpu_ftr_reg(SYS_ID_ISAR4_EL1, ID_ISAR4_SMC_SHIFT);
+		relax_cpu_ftr_reg(SYS_ID_PFR1_EL1, ID_PFR1_VIRT_FRAC_SHIFT);
+		relax_cpu_ftr_reg(SYS_ID_PFR1_EL1, ID_PFR1_SEC_FRAC_SHIFT);
+		relax_cpu_ftr_reg(SYS_ID_PFR1_EL1, ID_PFR1_VIRTUALIZATION_SHIFT);
+		relax_cpu_ftr_reg(SYS_ID_PFR1_EL1, ID_PFR1_SECURITY_SHIFT);
+		relax_cpu_ftr_reg(SYS_ID_PFR1_EL1, ID_PFR1_PROGMOD_SHIFT);
+	}
+
+	taint |= check_update_ftr_reg(SYS_ID_DFR0_EL1, cpu,
+				      info->reg_id_dfr0, boot->reg_id_dfr0);
+	taint |= check_update_ftr_reg(SYS_ID_DFR1_EL1, cpu,
+				      info->reg_id_dfr1, boot->reg_id_dfr1);
+	taint |= check_update_ftr_reg(SYS_ID_ISAR0_EL1, cpu,
+				      info->reg_id_isar0, boot->reg_id_isar0);
+	taint |= check_update_ftr_reg(SYS_ID_ISAR1_EL1, cpu,
+				      info->reg_id_isar1, boot->reg_id_isar1);
+	taint |= check_update_ftr_reg(SYS_ID_ISAR2_EL1, cpu,
+				      info->reg_id_isar2, boot->reg_id_isar2);
+	taint |= check_update_ftr_reg(SYS_ID_ISAR3_EL1, cpu,
+				      info->reg_id_isar3, boot->reg_id_isar3);
+	taint |= check_update_ftr_reg(SYS_ID_ISAR4_EL1, cpu,
+				      info->reg_id_isar4, boot->reg_id_isar4);
+	taint |= check_update_ftr_reg(SYS_ID_ISAR5_EL1, cpu,
+				      info->reg_id_isar5, boot->reg_id_isar5);
+	taint |= check_update_ftr_reg(SYS_ID_ISAR6_EL1, cpu,
+				      info->reg_id_isar6, boot->reg_id_isar6);
+
+	/*
+	 * Regardless of the value of the AuxReg field, the AIFSR, ADFSR, and
+	 * ACTLR formats could differ across CPUs and therefore would have to
+	 * be trapped for virtualization anyway.
+	 */
+	taint |= check_update_ftr_reg(SYS_ID_MMFR0_EL1, cpu,
+				      info->reg_id_mmfr0, boot->reg_id_mmfr0);
+	taint |= check_update_ftr_reg(SYS_ID_MMFR1_EL1, cpu,
+				      info->reg_id_mmfr1, boot->reg_id_mmfr1);
+	taint |= check_update_ftr_reg(SYS_ID_MMFR2_EL1, cpu,
+				      info->reg_id_mmfr2, boot->reg_id_mmfr2);
+	taint |= check_update_ftr_reg(SYS_ID_MMFR3_EL1, cpu,
+				      info->reg_id_mmfr3, boot->reg_id_mmfr3);
+	taint |= check_update_ftr_reg(SYS_ID_MMFR4_EL1, cpu,
+				      info->reg_id_mmfr4, boot->reg_id_mmfr4);
+	taint |= check_update_ftr_reg(SYS_ID_MMFR5_EL1, cpu,
+				      info->reg_id_mmfr5, boot->reg_id_mmfr5);
+	taint |= check_update_ftr_reg(SYS_ID_PFR0_EL1, cpu,
+				      info->reg_id_pfr0, boot->reg_id_pfr0);
+	taint |= check_update_ftr_reg(SYS_ID_PFR1_EL1, cpu,
+				      info->reg_id_pfr1, boot->reg_id_pfr1);
+	taint |= check_update_ftr_reg(SYS_ID_PFR2_EL1, cpu,
+				      info->reg_id_pfr2, boot->reg_id_pfr2);
+	taint |= check_update_ftr_reg(SYS_MVFR0_EL1, cpu,
+				      info->reg_mvfr0, boot->reg_mvfr0);
+	taint |= check_update_ftr_reg(SYS_MVFR1_EL1, cpu,
+				      info->reg_mvfr1, boot->reg_mvfr1);
+	taint |= check_update_ftr_reg(SYS_MVFR2_EL1, cpu,
+				      info->reg_mvfr2, boot->reg_mvfr2);
+
+	return taint;
+}
+
 /*
  * Update system wide CPU feature registers with the values from a
  * non-boot CPU. Also performs SANITY checks to make sure that there
@@ -753,9 +1026,6 @@ void update_cpu_features(int cpu,
 	taint |= check_update_ftr_reg(SYS_ID_AA64MMFR2_EL1, cpu,
 				      info->reg_id_aa64mmfr2, boot->reg_id_aa64mmfr2);
 
-	/*
-	 * EL3 is not our concern.
-	 */
 	taint |= check_update_ftr_reg(SYS_ID_AA64PFR0_EL1, cpu,
 				      info->reg_id_aa64pfr0, boot->reg_id_aa64pfr0);
 	taint |= check_update_ftr_reg(SYS_ID_AA64PFR1_EL1, cpu,
@@ -764,55 +1034,6 @@ void update_cpu_features(int cpu,
 	taint |= check_update_ftr_reg(SYS_ID_AA64ZFR0_EL1, cpu,
 				      info->reg_id_aa64zfr0, boot->reg_id_aa64zfr0);
 
-	/*
-	 * If we have AArch32, we care about 32-bit features for compat.
-	 * If the system doesn't support AArch32, don't update them.
-	 */
-	if (id_aa64pfr0_32bit_el0(read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1)) &&
-		id_aa64pfr0_32bit_el0(info->reg_id_aa64pfr0)) {
-
-		taint |= check_update_ftr_reg(SYS_ID_DFR0_EL1, cpu,
-					info->reg_id_dfr0, boot->reg_id_dfr0);
-		taint |= check_update_ftr_reg(SYS_ID_ISAR0_EL1, cpu,
-					info->reg_id_isar0, boot->reg_id_isar0);
-		taint |= check_update_ftr_reg(SYS_ID_ISAR1_EL1, cpu,
-					info->reg_id_isar1, boot->reg_id_isar1);
-		taint |= check_update_ftr_reg(SYS_ID_ISAR2_EL1, cpu,
-					info->reg_id_isar2, boot->reg_id_isar2);
-		taint |= check_update_ftr_reg(SYS_ID_ISAR3_EL1, cpu,
-					info->reg_id_isar3, boot->reg_id_isar3);
-		taint |= check_update_ftr_reg(SYS_ID_ISAR4_EL1, cpu,
-					info->reg_id_isar4, boot->reg_id_isar4);
-		taint |= check_update_ftr_reg(SYS_ID_ISAR5_EL1, cpu,
-					info->reg_id_isar5, boot->reg_id_isar5);
-		taint |= check_update_ftr_reg(SYS_ID_ISAR6_EL1, cpu,
-					info->reg_id_isar6, boot->reg_id_isar6);
-
-		/*
-		 * Regardless of the value of the AuxReg field, the AIFSR, ADFSR, and
-		 * ACTLR formats could differ across CPUs and therefore would have to
-		 * be trapped for virtualization anyway.
-		 */
-		taint |= check_update_ftr_reg(SYS_ID_MMFR0_EL1, cpu,
-					info->reg_id_mmfr0, boot->reg_id_mmfr0);
-		taint |= check_update_ftr_reg(SYS_ID_MMFR1_EL1, cpu,
-					info->reg_id_mmfr1, boot->reg_id_mmfr1);
-		taint |= check_update_ftr_reg(SYS_ID_MMFR2_EL1, cpu,
-					info->reg_id_mmfr2, boot->reg_id_mmfr2);
-		taint |= check_update_ftr_reg(SYS_ID_MMFR3_EL1, cpu,
-					info->reg_id_mmfr3, boot->reg_id_mmfr3);
-		taint |= check_update_ftr_reg(SYS_ID_PFR0_EL1, cpu,
-					info->reg_id_pfr0, boot->reg_id_pfr0);
-		taint |= check_update_ftr_reg(SYS_ID_PFR1_EL1, cpu,
-					info->reg_id_pfr1, boot->reg_id_pfr1);
-		taint |= check_update_ftr_reg(SYS_MVFR0_EL1, cpu,
-					info->reg_mvfr0, boot->reg_mvfr0);
-		taint |= check_update_ftr_reg(SYS_MVFR1_EL1, cpu,
-					info->reg_mvfr1, boot->reg_mvfr1);
-		taint |= check_update_ftr_reg(SYS_MVFR2_EL1, cpu,
-					info->reg_mvfr2, boot->reg_mvfr2);
-	}
-
 	if (id_aa64pfr0_sve(info->reg_id_aa64pfr0)) {
 		taint |= check_update_ftr_reg(SYS_ZCR_EL1, cpu,
 					info->reg_zcr, boot->reg_zcr);
@@ -824,6 +1045,12 @@ void update_cpu_features(int cpu,
 	}
 
 	/*
+	 * This relies on a sanitised view of the AArch64 ID registers
+	 * (e.g. SYS_ID_AA64PFR0_EL1), so we call it last.
+	 */
+	taint |= update_32bit_cpu_features(cpu, info, boot);
+
+	/*
 	 * Mismatched CPU features are a recipe for disaster. Don't even
 	 * pretend to support them.
 	 */
@@ -837,8 +1064,8 @@ u64 read_sanitised_ftr_reg(u32 id)
 {
 	struct arm64_ftr_reg *regp = get_arm64_ftr_reg(id);
 
-	/* We shouldn't get a request for an unsupported register */
-	BUG_ON(!regp);
+	if (!regp)
+		return 0;
 	return regp->sys_val;
 }
 
@@ -854,11 +1081,15 @@ static u64 __read_sysreg_by_encoding(u32 sys_id)
 	switch (sys_id) {
 	read_sysreg_case(SYS_ID_PFR0_EL1);
 	read_sysreg_case(SYS_ID_PFR1_EL1);
+	read_sysreg_case(SYS_ID_PFR2_EL1);
 	read_sysreg_case(SYS_ID_DFR0_EL1);
+	read_sysreg_case(SYS_ID_DFR1_EL1);
 	read_sysreg_case(SYS_ID_MMFR0_EL1);
 	read_sysreg_case(SYS_ID_MMFR1_EL1);
 	read_sysreg_case(SYS_ID_MMFR2_EL1);
 	read_sysreg_case(SYS_ID_MMFR3_EL1);
+	read_sysreg_case(SYS_ID_MMFR4_EL1);
+	read_sysreg_case(SYS_ID_MMFR5_EL1);
 	read_sysreg_case(SYS_ID_ISAR0_EL1);
 	read_sysreg_case(SYS_ID_ISAR1_EL1);
 	read_sysreg_case(SYS_ID_ISAR2_EL1);
@@ -1409,6 +1640,21 @@ static bool can_use_gic_priorities(const struct arm64_cpu_capabilities *entry,
 }
 #endif
 
+#ifdef CONFIG_ARM64_BTI
+static void bti_enable(const struct arm64_cpu_capabilities *__unused)
+{
+	/*
+	 * Use of X16/X17 for tail-calls and trampolines that jump to
+	 * function entry points using BR is a requirement for
+	 * marking binaries with GNU_PROPERTY_AARCH64_FEATURE_1_BTI.
+	 * So, be strict and forbid other BRs using other registers to
+	 * jump onto a PACIxSP instruction:
+	 */
+	sysreg_clear_set(sctlr_el1, 0, SCTLR_EL1_BT0 | SCTLR_EL1_BT1);
+	isb();
+}
+#endif /* CONFIG_ARM64_BTI */
+
 /* Internal helper functions to match cpu capability type */
 static bool
 cpucap_late_cpu_optional(const struct arm64_cpu_capabilities *cap)
@@ -1511,6 +1757,18 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
 		.field_pos = ID_AA64PFR0_EL0_SHIFT,
 		.min_field_value = ID_AA64PFR0_EL0_32BIT_64BIT,
 	},
+#ifdef CONFIG_KVM
+	{
+		.desc = "32-bit EL1 Support",
+		.capability = ARM64_HAS_32BIT_EL1,
+		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
+		.matches = has_cpuid_feature,
+		.sys_reg = SYS_ID_AA64PFR0_EL1,
+		.sign = FTR_UNSIGNED,
+		.field_pos = ID_AA64PFR0_EL1_SHIFT,
+		.min_field_value = ID_AA64PFR0_EL1_32BIT_64BIT,
+	},
+#endif
 	{
 		.desc = "Kernel page table isolation (KPTI)",
 		.capability = ARM64_UNMAP_KERNEL_AT_EL0,
@@ -1779,6 +2037,23 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
 		.min_field_value = 1,
 	},
 #endif
+#ifdef CONFIG_ARM64_BTI
+	{
+		.desc = "Branch Target Identification",
+		.capability = ARM64_BTI,
+#ifdef CONFIG_ARM64_BTI_KERNEL
+		.type = ARM64_CPUCAP_STRICT_BOOT_CPU_FEATURE,
+#else
+		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
+#endif
+		.matches = has_cpuid_feature,
+		.cpu_enable = bti_enable,
+		.sys_reg = SYS_ID_AA64PFR1_EL1,
+		.field_pos = ID_AA64PFR1_BT_SHIFT,
+		.min_field_value = ID_AA64PFR1_BT_BTI,
+		.sign = FTR_UNSIGNED,
+	},
+#endif
 	{},
 };
 
@@ -1888,6 +2163,9 @@ static const struct arm64_cpu_capabilities arm64_elf_hwcaps[] = {
 	HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_F64MM_SHIFT, FTR_UNSIGNED, ID_AA64ZFR0_F64MM, CAP_HWCAP, KERNEL_HWCAP_SVEF64MM),
 #endif
 	HWCAP_CAP(SYS_ID_AA64PFR1_EL1, ID_AA64PFR1_SSBS_SHIFT, FTR_UNSIGNED, ID_AA64PFR1_SSBS_PSTATE_INSNS, CAP_HWCAP, KERNEL_HWCAP_SSBS),
+#ifdef CONFIG_ARM64_BTI
+	HWCAP_CAP(SYS_ID_AA64PFR1_EL1, ID_AA64PFR1_BT_SHIFT, FTR_UNSIGNED, ID_AA64PFR1_BT_BTI, CAP_HWCAP, KERNEL_HWCAP_BTI),
+#endif
 #ifdef CONFIG_ARM64_PTR_AUTH
 	HWCAP_MULTI_CAP(ptr_auth_hwcap_addr_matches, CAP_HWCAP, KERNEL_HWCAP_PACA),
 	HWCAP_MULTI_CAP(ptr_auth_hwcap_gen_matches, CAP_HWCAP, KERNEL_HWCAP_PACG),
@@ -2181,6 +2459,36 @@ static void verify_sve_features(void)
 	/* Add checks on other ZCR bits here if necessary */
 }
 
+static void verify_hyp_capabilities(void)
+{
+	u64 safe_mmfr1, mmfr0, mmfr1;
+	int parange, ipa_max;
+	unsigned int safe_vmid_bits, vmid_bits;
+
+	if (!IS_ENABLED(CONFIG_KVM) || !IS_ENABLED(CONFIG_KVM_ARM_HOST))
+		return;
+
+	safe_mmfr1 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1);
+	mmfr0 = read_cpuid(ID_AA64MMFR0_EL1);
+	mmfr1 = read_cpuid(ID_AA64MMFR1_EL1);
+
+	/* Verify VMID bits */
+	safe_vmid_bits = get_vmid_bits(safe_mmfr1);
+	vmid_bits = get_vmid_bits(mmfr1);
+	if (vmid_bits < safe_vmid_bits) {
+		pr_crit("CPU%d: VMID width mismatch\n", smp_processor_id());
+		cpu_die_early();
+	}
+
+	/* Verify IPA range */
+	parange = cpuid_feature_extract_unsigned_field(mmfr0,
+				ID_AA64MMFR0_PARANGE_SHIFT);
+	ipa_max = id_aa64mmfr0_parange_to_phys_shift(parange);
+	if (ipa_max < get_kvm_ipa_limit()) {
+		pr_crit("CPU%d: IPA range mismatch\n", smp_processor_id());
+		cpu_die_early();
+	}
+}
 
 /*
  * Run through the enabled system capabilities and enable() it on this CPU.
@@ -2206,6 +2514,9 @@ static void verify_local_cpu_capabilities(void)
 
 	if (system_supports_sve())
 		verify_sve_features();
+
+	if (is_hyp_mode_available())
+		verify_hyp_capabilities();
 }
 
 void check_local_cpu_capabilities(void)
@@ -2394,7 +2705,7 @@ static int emulate_sys_reg(u32 id, u64 *valp)
 	if (sys_reg_CRm(id) == 0)
 		return emulate_id_reg(id, valp);
 
-	regp = get_arm64_ftr_reg(id);
+	regp = get_arm64_ftr_reg_nowarn(id);
 	if (regp)
 		*valp = arm64_ftr_reg_user_value(regp);
 	else
diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
index 86136075ae41..86637466daa8 100644
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -92,6 +92,7 @@ static const char *const hwcap_str[] = {
 	"bf16",
 	"dgh",
 	"rng",
+	"bti",
 	NULL
 };
 
@@ -311,6 +312,8 @@ static int __init cpuinfo_regs_init(void)
 	}
 	return 0;
 }
+device_initcall(cpuinfo_regs_init);
+
 static void cpuinfo_detect_icache_policy(struct cpuinfo_arm64 *info)
 {
 	unsigned int cpu = smp_processor_id();
@@ -362,6 +365,7 @@ static void __cpuinfo_store_cpu(struct cpuinfo_arm64 *info)
 	/* Update the 32bit ID registers only if AArch32 is implemented */
 	if (id_aa64pfr0_32bit_el0(info->reg_id_aa64pfr0)) {
 		info->reg_id_dfr0 = read_cpuid(ID_DFR0_EL1);
+		info->reg_id_dfr1 = read_cpuid(ID_DFR1_EL1);
 		info->reg_id_isar0 = read_cpuid(ID_ISAR0_EL1);
 		info->reg_id_isar1 = read_cpuid(ID_ISAR1_EL1);
 		info->reg_id_isar2 = read_cpuid(ID_ISAR2_EL1);
@@ -373,8 +377,11 @@ static void __cpuinfo_store_cpu(struct cpuinfo_arm64 *info)
 		info->reg_id_mmfr1 = read_cpuid(ID_MMFR1_EL1);
 		info->reg_id_mmfr2 = read_cpuid(ID_MMFR2_EL1);
 		info->reg_id_mmfr3 = read_cpuid(ID_MMFR3_EL1);
+		info->reg_id_mmfr4 = read_cpuid(ID_MMFR4_EL1);
+		info->reg_id_mmfr5 = read_cpuid(ID_MMFR5_EL1);
 		info->reg_id_pfr0 = read_cpuid(ID_PFR0_EL1);
 		info->reg_id_pfr1 = read_cpuid(ID_PFR1_EL1);
+		info->reg_id_pfr2 = read_cpuid(ID_PFR2_EL1);
 
 		info->reg_mvfr0 = read_cpuid(MVFR0_EL1);
 		info->reg_mvfr1 = read_cpuid(MVFR1_EL1);
@@ -403,5 +410,3 @@ void __init cpuinfo_store_boot_cpu(void)
 	boot_cpu_data = *info;
 	init_cpu_features(&boot_cpu_data);
 }
-
-device_initcall(cpuinfo_regs_init);
diff --git a/arch/arm64/kernel/crash_core.c b/arch/arm64/kernel/crash_core.c
index ca4c3e12d8c5..1f646b07e3e9 100644
--- a/arch/arm64/kernel/crash_core.c
+++ b/arch/arm64/kernel/crash_core.c
@@ -5,6 +5,7 @@
  */
 
 #include <linux/crash_core.h>
+#include <asm/cpufeature.h>
 #include <asm/memory.h>
 
 void arch_crash_save_vmcoreinfo(void)
@@ -16,4 +17,7 @@ void arch_crash_save_vmcoreinfo(void)
 	vmcoreinfo_append_str("NUMBER(PHYS_OFFSET)=0x%llx\n",
 						PHYS_OFFSET);
 	vmcoreinfo_append_str("KERNELOFFSET=%lx\n", kaslr_offset());
+	vmcoreinfo_append_str("NUMBER(KERNELPACMASK)=0x%llx\n",
+						system_supports_address_auth() ?
+						ptrauth_kernel_pac_mask() : 0);
 }
diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c
index 48222a4760c2..15e80c876d46 100644
--- a/arch/arm64/kernel/debug-monitors.c
+++ b/arch/arm64/kernel/debug-monitors.c
@@ -376,15 +376,13 @@ int aarch32_break_handler(struct pt_regs *regs)
 }
 NOKPROBE_SYMBOL(aarch32_break_handler);
 
-static int __init debug_traps_init(void)
+void __init debug_traps_init(void)
 {
 	hook_debug_fault_code(DBG_ESR_EVT_HWSS, single_step_handler, SIGTRAP,
 			      TRAP_TRACE, "single-step handler");
 	hook_debug_fault_code(DBG_ESR_EVT_BRK, brk_handler, SIGTRAP,
 			      TRAP_BRKPT, "ptrace BRK handler");
-	return 0;
 }
-arch_initcall(debug_traps_init);
 
 /* Re-enable single step for syscall restarting. */
 void user_rewind_single_step(struct task_struct *task)
diff --git a/arch/arm64/kernel/efi-entry.S b/arch/arm64/kernel/efi-entry.S
index 5664af1e9260..0073b24b5d25 100644
--- a/arch/arm64/kernel/efi-entry.S
+++ b/arch/arm64/kernel/efi-entry.S
@@ -19,7 +19,7 @@ SYM_CODE_START(efi_enter_kernel)
 	 * point stored in x0. Save those values in registers which are
 	 * callee preserved.
 	 */
-	ldr	w2, =stext_offset
+	ldr	w2, =primary_entry_offset
 	add	x19, x0, x2		// relocated Image entrypoint
 	mov	x20, x1			// DTB address
 
diff --git a/arch/arm64/kernel/efi-header.S b/arch/arm64/kernel/efi-header.S
index f2457d4b76a4..df67c0f2a077 100644
--- a/arch/arm64/kernel/efi-header.S
+++ b/arch/arm64/kernel/efi-header.S
@@ -32,7 +32,7 @@ optional_header:
 
 extra_header_fields:
 	.quad	0					// ImageBase
-	.long	SZ_4K					// SectionAlignment
+	.long	SEGMENT_ALIGN				// SectionAlignment
 	.long	PECOFF_FILE_ALIGNMENT			// FileAlignment
 	.short	0					// MajorOperatingSystemVersion
 	.short	0					// MinorOperatingSystemVersion
diff --git a/arch/arm64/kernel/efi-rt-wrapper.S b/arch/arm64/kernel/efi-rt-wrapper.S
index 3fc71106cb2b..75691a2641c1 100644
--- a/arch/arm64/kernel/efi-rt-wrapper.S
+++ b/arch/arm64/kernel/efi-rt-wrapper.S
@@ -5,7 +5,7 @@
 
 #include <linux/linkage.h>
 
-ENTRY(__efi_rt_asm_wrapper)
+SYM_FUNC_START(__efi_rt_asm_wrapper)
 	stp	x29, x30, [sp, #-32]!
 	mov	x29, sp
 
@@ -34,5 +34,14 @@ ENTRY(__efi_rt_asm_wrapper)
 	ldp	x29, x30, [sp], #32
 	b.ne	0f
 	ret
-0:	b	efi_handle_corrupted_x18	// tail call
-ENDPROC(__efi_rt_asm_wrapper)
+0:
+	/*
+	 * With CONFIG_SHADOW_CALL_STACK, the kernel uses x18 to store a
+	 * shadow stack pointer, which we need to restore before returning to
+	 * potentially instrumented code. This is safe because the wrapper is
+	 * called with preemption disabled and a separate shadow stack is used
+	 * for interrupts.
+	 */
+	mov	x18, x2
+	b	efi_handle_corrupted_x18	// tail call
+SYM_FUNC_END(__efi_rt_asm_wrapper)
diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c
index c839b5bf1904..3dbdf9752b11 100644
--- a/arch/arm64/kernel/entry-common.c
+++ b/arch/arm64/kernel/entry-common.c
@@ -94,7 +94,7 @@ asmlinkage void notrace el1_sync_handler(struct pt_regs *regs)
 		break;
 	default:
 		el1_inv(regs, esr);
-	};
+	}
 }
 NOKPROBE_SYMBOL(el1_sync_handler);
 
@@ -188,6 +188,14 @@ static void notrace el0_undef(struct pt_regs *regs)
 }
 NOKPROBE_SYMBOL(el0_undef);
 
+static void notrace el0_bti(struct pt_regs *regs)
+{
+	user_exit_irqoff();
+	local_daif_restore(DAIF_PROCCTX);
+	do_bti(regs);
+}
+NOKPROBE_SYMBOL(el0_bti);
+
 static void notrace el0_inv(struct pt_regs *regs, unsigned long esr)
 {
 	user_exit_irqoff();
@@ -255,6 +263,9 @@ asmlinkage void notrace el0_sync_handler(struct pt_regs *regs)
 	case ESR_ELx_EC_UNKNOWN:
 		el0_undef(regs);
 		break;
+	case ESR_ELx_EC_BTI:
+		el0_bti(regs);
+		break;
 	case ESR_ELx_EC_BREAKPT_LOW:
 	case ESR_ELx_EC_SOFTSTP_LOW:
 	case ESR_ELx_EC_WATCHPT_LOW:
diff --git a/arch/arm64/kernel/entry-fpsimd.S b/arch/arm64/kernel/entry-fpsimd.S
index 0f24eae8f3cc..f880dd63ddc3 100644
--- a/arch/arm64/kernel/entry-fpsimd.S
+++ b/arch/arm64/kernel/entry-fpsimd.S
@@ -16,34 +16,34 @@
  *
  * x0 - pointer to struct fpsimd_state
  */
-ENTRY(fpsimd_save_state)
+SYM_FUNC_START(fpsimd_save_state)
 	fpsimd_save x0, 8
 	ret
-ENDPROC(fpsimd_save_state)
+SYM_FUNC_END(fpsimd_save_state)
 
 /*
  * Load the FP registers.
  *
  * x0 - pointer to struct fpsimd_state
  */
-ENTRY(fpsimd_load_state)
+SYM_FUNC_START(fpsimd_load_state)
 	fpsimd_restore x0, 8
 	ret
-ENDPROC(fpsimd_load_state)
+SYM_FUNC_END(fpsimd_load_state)
 
 #ifdef CONFIG_ARM64_SVE
-ENTRY(sve_save_state)
+SYM_FUNC_START(sve_save_state)
 	sve_save 0, x1, 2
 	ret
-ENDPROC(sve_save_state)
+SYM_FUNC_END(sve_save_state)
 
-ENTRY(sve_load_state)
+SYM_FUNC_START(sve_load_state)
 	sve_load 0, x1, x2, 3, x4
 	ret
-ENDPROC(sve_load_state)
+SYM_FUNC_END(sve_load_state)
 
-ENTRY(sve_get_vl)
+SYM_FUNC_START(sve_get_vl)
 	_sve_rdvl	0, 1
 	ret
-ENDPROC(sve_get_vl)
+SYM_FUNC_END(sve_get_vl)
 #endif /* CONFIG_ARM64_SVE */
diff --git a/arch/arm64/kernel/entry-ftrace.S b/arch/arm64/kernel/entry-ftrace.S
index 833d48c9acb5..a338f40e64d3 100644
--- a/arch/arm64/kernel/entry-ftrace.S
+++ b/arch/arm64/kernel/entry-ftrace.S
@@ -23,8 +23,9 @@
  *
  * ... where <entry> is either ftrace_caller or ftrace_regs_caller.
  *
- * Each instrumented function follows the AAPCS, so here x0-x8 and x19-x30 are
- * live, and x9-x18 are safe to clobber.
+ * Each instrumented function follows the AAPCS, so here x0-x8 and x18-x30 are
+ * live (x18 holds the Shadow Call Stack pointer), and x9-x17 are safe to
+ * clobber.
  *
  * We save the callsite's context into a pt_regs before invoking any ftrace
  * callbacks. So that we can get a sensible backtrace, we create a stack record
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index ddcde093c433..5304d193c79d 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -23,6 +23,7 @@
 #include <asm/mmu.h>
 #include <asm/processor.h>
 #include <asm/ptrace.h>
+#include <asm/scs.h>
 #include <asm/thread_info.h>
 #include <asm/asm-uaccess.h>
 #include <asm/unistd.h>
@@ -178,7 +179,9 @@ alternative_cb_end
 
 	apply_ssbd 1, x22, x23
 
-	ptrauth_keys_install_kernel tsk, 1, x20, x22, x23
+	ptrauth_keys_install_kernel tsk, x20, x22, x23
+
+	scs_load tsk, x20
 	.else
 	add	x21, sp, #S_FRAME_SIZE
 	get_current_task tsk
@@ -343,6 +346,8 @@ alternative_else_nop_endif
 	msr	cntkctl_el1, x1
 4:
 #endif
+	scs_save tsk, x0
+
 	/* No kernel C function calls after this as user keys are set. */
 	ptrauth_keys_install_user tsk, x0, x1, x2
 
@@ -388,6 +393,9 @@ alternative_insn eret, nop, ARM64_UNMAP_KERNEL_AT_EL0
 
 	.macro	irq_stack_entry
 	mov	x19, sp			// preserve the original sp
+#ifdef CONFIG_SHADOW_CALL_STACK
+	mov	x24, scs_sp		// preserve the original shadow stack
+#endif
 
 	/*
 	 * Compare sp with the base of the task stack.
@@ -405,15 +413,25 @@ alternative_insn eret, nop, ARM64_UNMAP_KERNEL_AT_EL0
 
 	/* switch to the irq stack */
 	mov	sp, x26
+
+#ifdef CONFIG_SHADOW_CALL_STACK
+	/* also switch to the irq shadow stack */
+	adr_this_cpu scs_sp, irq_shadow_call_stack, x26
+#endif
+
 9998:
 	.endm
 
 	/*
-	 * x19 should be preserved between irq_stack_entry and
-	 * irq_stack_exit.
+	 * The callee-saved regs (x19-x29) should be preserved between
+	 * irq_stack_entry and irq_stack_exit, but note that kernel_entry
+	 * uses x20-x23 to store data for later use.
 	 */
 	.macro	irq_stack_exit
 	mov	sp, x19
+#ifdef CONFIG_SHADOW_CALL_STACK
+	mov	scs_sp, x24
+#endif
 	.endm
 
 /* GPRs used by entry code */
@@ -728,20 +746,9 @@ el0_error_naked:
 SYM_CODE_END(el0_error)
 
 /*
- * Ok, we need to do extra processing, enter the slow path.
- */
-work_pending:
-	mov	x0, sp				// 'regs'
-	bl	do_notify_resume
-#ifdef CONFIG_TRACE_IRQFLAGS
-	bl	trace_hardirqs_on		// enabled while in userspace
-#endif
-	ldr	x1, [tsk, #TSK_TI_FLAGS]	// re-check for single-step
-	b	finish_ret_to_user
-/*
  * "slow" syscall return path.
  */
-ret_to_user:
+SYM_CODE_START_LOCAL(ret_to_user)
 	disable_daif
 	gic_prio_kentry_setup tmp=x3
 	ldr	x1, [tsk, #TSK_TI_FLAGS]
@@ -753,7 +760,19 @@ finish_ret_to_user:
 	bl	stackleak_erase
 #endif
 	kernel_exit 0
-ENDPROC(ret_to_user)
+
+/*
+ * Ok, we need to do extra processing, enter the slow path.
+ */
+work_pending:
+	mov	x0, sp				// 'regs'
+	bl	do_notify_resume
+#ifdef CONFIG_TRACE_IRQFLAGS
+	bl	trace_hardirqs_on		// enabled while in userspace
+#endif
+	ldr	x1, [tsk, #TSK_TI_FLAGS]	// re-check for single-step
+	b	finish_ret_to_user
+SYM_CODE_END(ret_to_user)
 
 	.popsection				// .entry.text
 
@@ -900,7 +919,9 @@ SYM_FUNC_START(cpu_switch_to)
 	ldr	lr, [x8]
 	mov	sp, x9
 	msr	sp_el0, x1
-	ptrauth_keys_install_kernel x1, 1, x8, x9, x10
+	ptrauth_keys_install_kernel x1, x8, x9, x10
+	scs_save x0, x8
+	scs_load x1, x8
 	ret
 SYM_FUNC_END(cpu_switch_to)
 NOKPROBE(cpu_switch_to)
@@ -1029,13 +1050,16 @@ SYM_CODE_START(__sdei_asm_handler)
 
 	mov	x19, x1
 
+#if defined(CONFIG_VMAP_STACK) || defined(CONFIG_SHADOW_CALL_STACK)
+	ldrb	w4, [x19, #SDEI_EVENT_PRIORITY]
+#endif
+
 #ifdef CONFIG_VMAP_STACK
 	/*
 	 * entry.S may have been using sp as a scratch register, find whether
 	 * this is a normal or critical event and switch to the appropriate
 	 * stack for this CPU.
 	 */
-	ldrb	w4, [x19, #SDEI_EVENT_PRIORITY]
 	cbnz	w4, 1f
 	ldr_this_cpu dst=x5, sym=sdei_stack_normal_ptr, tmp=x6
 	b	2f
@@ -1045,6 +1069,15 @@ SYM_CODE_START(__sdei_asm_handler)
 	mov	sp, x5
 #endif
 
+#ifdef CONFIG_SHADOW_CALL_STACK
+	/* Use a separate shadow call stack for normal and critical events */
+	cbnz	w4, 3f
+	adr_this_cpu dst=scs_sp, sym=sdei_shadow_call_stack_normal, tmp=x6
+	b	4f
+3:	adr_this_cpu dst=scs_sp, sym=sdei_shadow_call_stack_critical, tmp=x6
+4:
+#endif
+
 	/*
 	 * We may have interrupted userspace, or a guest, or exit-from or
 	 * return-to either of these. We can't trust sp_el0, restore it.
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 57a91032b4c2..632702146813 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -13,6 +13,7 @@
 #include <linux/init.h>
 #include <linux/irqchip/arm-gic-v3.h>
 
+#include <asm/asm_pointer_auth.h>
 #include <asm/assembler.h>
 #include <asm/boot.h>
 #include <asm/ptrace.h>
@@ -27,6 +28,7 @@
 #include <asm/pgtable-hwdef.h>
 #include <asm/pgtable.h>
 #include <asm/page.h>
+#include <asm/scs.h>
 #include <asm/smp.h>
 #include <asm/sysreg.h>
 #include <asm/thread_info.h>
@@ -70,9 +72,9 @@ _head:
 	 * its opcode forms the magic "MZ" signature required by UEFI.
 	 */
 	add	x13, x18, #0x16
-	b	stext
+	b	primary_entry
 #else
-	b	stext				// branch to kernel start, magic
+	b	primary_entry			// branch to kernel start, magic
 	.long	0				// reserved
 #endif
 	le64sym	_kernel_offset_le		// Image load offset from start of RAM, little-endian
@@ -98,14 +100,13 @@ pe_header:
 	 * primary lowlevel boot path:
 	 *
 	 *  Register   Scope                      Purpose
-	 *  x21        stext() .. start_kernel()  FDT pointer passed at boot in x0
-	 *  x23        stext() .. start_kernel()  physical misalignment/KASLR offset
-	 *  x28        __create_page_tables()     callee preserved temp register
-	 *  x19/x20    __primary_switch()         callee preserved temp registers
-	 *  x24        __primary_switch() .. relocate_kernel()
-	 *                                        current RELR displacement
+	 *  x21        primary_entry() .. start_kernel()        FDT pointer passed at boot in x0
+	 *  x23        primary_entry() .. start_kernel()        physical misalignment/KASLR offset
+	 *  x28        __create_page_tables()                   callee preserved temp register
+	 *  x19/x20    __primary_switch()                       callee preserved temp registers
+	 *  x24        __primary_switch() .. relocate_kernel()  current RELR displacement
 	 */
-SYM_CODE_START(stext)
+SYM_CODE_START(primary_entry)
 	bl	preserve_boot_args
 	bl	el2_setup			// Drop to EL1, w0=cpu_boot_mode
 	adrp	x23, __PHYS_OFFSET
@@ -118,10 +119,9 @@ SYM_CODE_START(stext)
 	 * On return, the CPU will be ready for the MMU to be turned on and
 	 * the TCR will have been set.
 	 */
-	mov	x0, #ARM64_CPU_BOOT_PRIMARY
 	bl	__cpu_setup			// initialise processor
 	b	__primary_switch
-SYM_CODE_END(stext)
+SYM_CODE_END(primary_entry)
 
 /*
  * Preserve the arguments passed by the bootloader in x0 .. x3
@@ -394,13 +394,19 @@ SYM_FUNC_START_LOCAL(__create_page_tables)
 
 	/*
 	 * Since the page tables have been populated with non-cacheable
-	 * accesses (MMU disabled), invalidate the idmap and swapper page
-	 * tables again to remove any speculatively loaded cache lines.
+	 * accesses (MMU disabled), invalidate those tables again to
+	 * remove any speculatively loaded cache lines.
 	 */
+	dmb	sy
+
 	adrp	x0, idmap_pg_dir
+	adrp	x1, idmap_pg_end
+	sub	x1, x1, x0
+	bl	__inval_dcache_area
+
+	adrp	x0, init_pg_dir
 	adrp	x1, init_pg_end
 	sub	x1, x1, x0
-	dmb	sy
 	bl	__inval_dcache_area
 
 	ret	x28
@@ -417,6 +423,10 @@ SYM_FUNC_START_LOCAL(__primary_switched)
 	adr_l	x5, init_task
 	msr	sp_el0, x5			// Save thread_info
 
+#ifdef CONFIG_ARM64_PTR_AUTH
+	__ptrauth_keys_init_cpu	x5, x6, x7, x8
+#endif
+
 	adr_l	x8, vectors			// load VBAR_EL1 with virtual
 	msr	vbar_el1, x8			// vector table address
 	isb
@@ -424,6 +434,10 @@ SYM_FUNC_START_LOCAL(__primary_switched)
 	stp	xzr, x30, [sp, #-16]!
 	mov	x29, sp
 
+#ifdef CONFIG_SHADOW_CALL_STACK
+	adr_l	scs_sp, init_shadow_call_stack	// Set shadow call stack
+#endif
+
 	str_l	x21, __fdt_pointer, x5		// Save FDT pointer
 
 	ldr_l	x4, kimage_vaddr		// Save the offset between
@@ -717,7 +731,6 @@ SYM_FUNC_START_LOCAL(secondary_startup)
 	 * Common entry point for secondary CPUs.
 	 */
 	bl	__cpu_secondary_check52bitva
-	mov	x0, #ARM64_CPU_BOOT_SECONDARY
 	bl	__cpu_setup			// initialise processor
 	adrp	x1, swapper_pg_dir
 	bl	__enable_mmu
@@ -737,8 +750,14 @@ SYM_FUNC_START_LOCAL(__secondary_switched)
 	ldr	x2, [x0, #CPU_BOOT_TASK]
 	cbz	x2, __secondary_too_slow
 	msr	sp_el0, x2
+	scs_load x2, x3
 	mov	x29, #0
 	mov	x30, #0
+
+#ifdef CONFIG_ARM64_PTR_AUTH
+	ptrauth_keys_init_cpu x2, x3, x4, x5
+#endif
+
 	b	secondary_start_kernel
 SYM_FUNC_END(__secondary_switched)
 
diff --git a/arch/arm64/kernel/hibernate-asm.S b/arch/arm64/kernel/hibernate-asm.S
index 6532105b3e32..8ccca660034e 100644
--- a/arch/arm64/kernel/hibernate-asm.S
+++ b/arch/arm64/kernel/hibernate-asm.S
@@ -65,7 +65,7 @@
  * x5: physical address of a  zero page that remains zero after resume
  */
 .pushsection    ".hibernate_exit.text", "ax"
-ENTRY(swsusp_arch_suspend_exit)
+SYM_CODE_START(swsusp_arch_suspend_exit)
 	/*
 	 * We execute from ttbr0, change ttbr1 to our copied linear map tables
 	 * with a break-before-make via the zero page
@@ -110,7 +110,7 @@ ENTRY(swsusp_arch_suspend_exit)
 	cbz	x24, 3f		/* Do we need to re-initialise EL2? */
 	hvc	#0
 3:	ret
-ENDPROC(swsusp_arch_suspend_exit)
+SYM_CODE_END(swsusp_arch_suspend_exit)
 
 /*
  * Restore the hyp stub.
@@ -119,15 +119,15 @@ ENDPROC(swsusp_arch_suspend_exit)
  *
  * x24: The physical address of __hyp_stub_vectors
  */
-el1_sync:
+SYM_CODE_START_LOCAL(el1_sync)
 	msr	vbar_el2, x24
 	eret
-ENDPROC(el1_sync)
+SYM_CODE_END(el1_sync)
 
 .macro invalid_vector	label
-\label:
+SYM_CODE_START_LOCAL(\label)
 	b \label
-ENDPROC(\label)
+SYM_CODE_END(\label)
 .endm
 
 	invalid_vector	el2_sync_invalid
@@ -141,7 +141,7 @@ ENDPROC(\label)
 
 /* el2 vectors - switch el2 here while we restore the memory image. */
 	.align 11
-ENTRY(hibernate_el2_vectors)
+SYM_CODE_START(hibernate_el2_vectors)
 	ventry	el2_sync_invalid		// Synchronous EL2t
 	ventry	el2_irq_invalid			// IRQ EL2t
 	ventry	el2_fiq_invalid			// FIQ EL2t
@@ -161,6 +161,6 @@ ENTRY(hibernate_el2_vectors)
 	ventry	el1_irq_invalid			// IRQ 32-bit EL1
 	ventry	el1_fiq_invalid			// FIQ 32-bit EL1
 	ventry	el1_error_invalid		// Error 32-bit EL1
-END(hibernate_el2_vectors)
+SYM_CODE_END(hibernate_el2_vectors)
 
 .popsection
diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index e473ead806ed..160f5881a0b7 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -21,7 +21,7 @@
 
 	.align 11
 
-ENTRY(__hyp_stub_vectors)
+SYM_CODE_START(__hyp_stub_vectors)
 	ventry	el2_sync_invalid		// Synchronous EL2t
 	ventry	el2_irq_invalid			// IRQ EL2t
 	ventry	el2_fiq_invalid			// FIQ EL2t
@@ -41,11 +41,11 @@ ENTRY(__hyp_stub_vectors)
 	ventry	el1_irq_invalid			// IRQ 32-bit EL1
 	ventry	el1_fiq_invalid			// FIQ 32-bit EL1
 	ventry	el1_error_invalid		// Error 32-bit EL1
-ENDPROC(__hyp_stub_vectors)
+SYM_CODE_END(__hyp_stub_vectors)
 
 	.align 11
 
-el1_sync:
+SYM_CODE_START_LOCAL(el1_sync)
 	cmp	x0, #HVC_SET_VECTORS
 	b.ne	2f
 	msr	vbar_el2, x1
@@ -68,12 +68,12 @@ el1_sync:
 
 9:	mov	x0, xzr
 	eret
-ENDPROC(el1_sync)
+SYM_CODE_END(el1_sync)
 
 .macro invalid_vector	label
-\label:
+SYM_CODE_START_LOCAL(\label)
 	b \label
-ENDPROC(\label)
+SYM_CODE_END(\label)
 .endm
 
 	invalid_vector	el2_sync_invalid
@@ -106,15 +106,15 @@ ENDPROC(\label)
  * initialisation entry point.
  */
 
-ENTRY(__hyp_set_vectors)
+SYM_FUNC_START(__hyp_set_vectors)
 	mov	x1, x0
 	mov	x0, #HVC_SET_VECTORS
 	hvc	#0
 	ret
-ENDPROC(__hyp_set_vectors)
+SYM_FUNC_END(__hyp_set_vectors)
 
-ENTRY(__hyp_reset_vectors)
+SYM_FUNC_START(__hyp_reset_vectors)
 	mov	x0, #HVC_RESET_VECTORS
 	hvc	#0
 	ret
-ENDPROC(__hyp_reset_vectors)
+SYM_FUNC_END(__hyp_reset_vectors)
diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h
index 7f06ad93fc95..be0a63ffed23 100644
--- a/arch/arm64/kernel/image-vars.h
+++ b/arch/arm64/kernel/image-vars.h
@@ -13,7 +13,7 @@
 #ifdef CONFIG_EFI
 
 __efistub_kernel_size		= _edata - _text;
-__efistub_stext_offset		= stext - _text;
+__efistub_primary_entry_offset	= primary_entry - _text;
 
 
 /*
diff --git a/arch/arm64/kernel/insn.c b/arch/arm64/kernel/insn.c
index 4a9e773a177f..684d871ae38d 100644
--- a/arch/arm64/kernel/insn.c
+++ b/arch/arm64/kernel/insn.c
@@ -51,21 +51,33 @@ enum aarch64_insn_encoding_class __kprobes aarch64_get_insn_class(u32 insn)
 	return aarch64_insn_encoding_class[(insn >> 25) & 0xf];
 }
 
-/* NOP is an alias of HINT */
-bool __kprobes aarch64_insn_is_nop(u32 insn)
+bool __kprobes aarch64_insn_is_steppable_hint(u32 insn)
 {
 	if (!aarch64_insn_is_hint(insn))
 		return false;
 
 	switch (insn & 0xFE0) {
-	case AARCH64_INSN_HINT_YIELD:
-	case AARCH64_INSN_HINT_WFE:
-	case AARCH64_INSN_HINT_WFI:
-	case AARCH64_INSN_HINT_SEV:
-	case AARCH64_INSN_HINT_SEVL:
-		return false;
-	default:
+	case AARCH64_INSN_HINT_XPACLRI:
+	case AARCH64_INSN_HINT_PACIA_1716:
+	case AARCH64_INSN_HINT_PACIB_1716:
+	case AARCH64_INSN_HINT_AUTIA_1716:
+	case AARCH64_INSN_HINT_AUTIB_1716:
+	case AARCH64_INSN_HINT_PACIAZ:
+	case AARCH64_INSN_HINT_PACIASP:
+	case AARCH64_INSN_HINT_PACIBZ:
+	case AARCH64_INSN_HINT_PACIBSP:
+	case AARCH64_INSN_HINT_AUTIAZ:
+	case AARCH64_INSN_HINT_AUTIASP:
+	case AARCH64_INSN_HINT_AUTIBZ:
+	case AARCH64_INSN_HINT_AUTIBSP:
+	case AARCH64_INSN_HINT_BTI:
+	case AARCH64_INSN_HINT_BTIC:
+	case AARCH64_INSN_HINT_BTIJ:
+	case AARCH64_INSN_HINT_BTIJC:
+	case AARCH64_INSN_HINT_NOP:
 		return true;
+	default:
+		return false;
 	}
 }
 
@@ -574,7 +586,7 @@ u32 aarch64_insn_gen_cond_branch_imm(unsigned long pc, unsigned long addr,
 					     offset >> 2);
 }
 
-u32 __kprobes aarch64_insn_gen_hint(enum aarch64_insn_hint_op op)
+u32 __kprobes aarch64_insn_gen_hint(enum aarch64_insn_hint_cr_op op)
 {
 	return aarch64_insn_get_hint_value() | op;
 }
@@ -1535,16 +1547,10 @@ static u32 aarch64_encode_immediate(u64 imm,
 				    u32 insn)
 {
 	unsigned int immr, imms, n, ones, ror, esz, tmp;
-	u64 mask = ~0UL;
-
-	/* Can't encode full zeroes or full ones */
-	if (!imm || !~imm)
-		return AARCH64_BREAK_FAULT;
+	u64 mask;
 
 	switch (variant) {
 	case AARCH64_INSN_VARIANT_32BIT:
-		if (upper_32_bits(imm))
-			return AARCH64_BREAK_FAULT;
 		esz = 32;
 		break;
 	case AARCH64_INSN_VARIANT_64BIT:
@@ -1556,6 +1562,12 @@ static u32 aarch64_encode_immediate(u64 imm,
 		return AARCH64_BREAK_FAULT;
 	}
 
+	mask = GENMASK(esz - 1, 0);
+
+	/* Can't encode full zeroes, full ones, or value wider than the mask */
+	if (!imm || imm == mask || imm & ~mask)
+		return AARCH64_BREAK_FAULT;
+
 	/*
 	 * Inverse of Replicate(). Try to spot a repeating pattern
 	 * with a pow2 stride.
diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c
index b40c3b0def92..522e6f517ec0 100644
--- a/arch/arm64/kernel/machine_kexec_file.c
+++ b/arch/arm64/kernel/machine_kexec_file.c
@@ -138,12 +138,12 @@ static int setup_dtb(struct kimage *image,
 
 	/* add rng-seed */
 	if (rng_is_initialized()) {
-		u8 rng_seed[RNG_SEED_SIZE];
-		get_random_bytes(rng_seed, RNG_SEED_SIZE);
-		ret = fdt_setprop(dtb, off, FDT_PROP_RNG_SEED, rng_seed,
-				RNG_SEED_SIZE);
+		void *rng_seed;
+		ret = fdt_setprop_placeholder(dtb, off, FDT_PROP_RNG_SEED,
+				RNG_SEED_SIZE, &rng_seed);
 		if (ret)
 			goto out;
+		get_random_bytes(rng_seed, RNG_SEED_SIZE);
 	} else {
 		pr_notice("RNG is not initialised: omitting \"%s\" property\n",
 				FDT_PROP_RNG_SEED);
@@ -284,7 +284,7 @@ int load_other_segments(struct kimage *image,
 		image->arch.elf_headers_sz = headers_sz;
 
 		pr_debug("Loaded elf core header at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
-			 image->arch.elf_headers_mem, headers_sz, headers_sz);
+			 image->arch.elf_headers_mem, kbuf.bufsz, kbuf.memsz);
 	}
 
 	/* load initrd */
@@ -305,7 +305,7 @@ int load_other_segments(struct kimage *image,
 		initrd_load_addr = kbuf.mem;
 
 		pr_debug("Loaded initrd at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
-				initrd_load_addr, initrd_len, initrd_len);
+				initrd_load_addr, kbuf.bufsz, kbuf.memsz);
 	}
 
 	/* load dtb */
@@ -332,7 +332,7 @@ int load_other_segments(struct kimage *image,
 	image->arch.dtb_mem = kbuf.mem;
 
 	pr_debug("Loaded dtb at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
-			kbuf.mem, dtb_len, dtb_len);
+			kbuf.mem, kbuf.bufsz, kbuf.memsz);
 
 	return 0;
 
diff --git a/arch/arm64/kernel/paravirt.c b/arch/arm64/kernel/paravirt.c
index 1ef702b0be2d..295d66490584 100644
--- a/arch/arm64/kernel/paravirt.c
+++ b/arch/arm64/kernel/paravirt.c
@@ -120,7 +120,7 @@ static bool has_pv_steal_clock(void)
 	struct arm_smccc_res res;
 
 	/* To detect the presence of PV time support we require SMCCC 1.1+ */
-	if (psci_ops.smccc_version < SMCCC_VERSION_1_1)
+	if (arm_smccc_1_1_get_conduit() == SMCCC_CONDUIT_NONE)
 		return false;
 
 	arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
diff --git a/arch/arm64/kernel/probes/decode-insn.c b/arch/arm64/kernel/probes/decode-insn.c
index b78fac9e546c..263d5fba4c8a 100644
--- a/arch/arm64/kernel/probes/decode-insn.c
+++ b/arch/arm64/kernel/probes/decode-insn.c
@@ -46,7 +46,7 @@ static bool __kprobes aarch64_insn_is_steppable(u32 insn)
 		 * except for the NOP case.
 		 */
 		if (aarch64_insn_is_hint(insn))
-			return aarch64_insn_is_nop(insn);
+			return aarch64_insn_is_steppable_hint(insn);
 
 		return true;
 	}
diff --git a/arch/arm64/kernel/probes/kprobes_trampoline.S b/arch/arm64/kernel/probes/kprobes_trampoline.S
index 45dce03aaeaf..890ca72c5a51 100644
--- a/arch/arm64/kernel/probes/kprobes_trampoline.S
+++ b/arch/arm64/kernel/probes/kprobes_trampoline.S
@@ -61,7 +61,7 @@
 	ldp x28, x29, [sp, #S_X28]
 	.endm
 
-ENTRY(kretprobe_trampoline)
+SYM_CODE_START(kretprobe_trampoline)
 	sub sp, sp, #S_FRAME_SIZE
 
 	save_all_base_regs
@@ -79,4 +79,4 @@ ENTRY(kretprobe_trampoline)
 	add sp, sp, #S_FRAME_SIZE
 	ret
 
-ENDPROC(kretprobe_trampoline)
+SYM_CODE_END(kretprobe_trampoline)
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 56be4cbf771f..eade7807e819 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -11,6 +11,7 @@
 
 #include <linux/compat.h>
 #include <linux/efi.h>
+#include <linux/elf.h>
 #include <linux/export.h>
 #include <linux/sched.h>
 #include <linux/sched/debug.h>
@@ -18,6 +19,7 @@
 #include <linux/sched/task_stack.h>
 #include <linux/kernel.h>
 #include <linux/lockdep.h>
+#include <linux/mman.h>
 #include <linux/mm.h>
 #include <linux/stddef.h>
 #include <linux/sysctl.h>
@@ -209,6 +211,15 @@ void machine_restart(char *cmd)
 	while (1);
 }
 
+#define bstr(suffix, str) [PSR_BTYPE_ ## suffix >> PSR_BTYPE_SHIFT] = str
+static const char *const btypes[] = {
+	bstr(NONE, "--"),
+	bstr(  JC, "jc"),
+	bstr(   C, "-c"),
+	bstr(  J , "j-")
+};
+#undef bstr
+
 static void print_pstate(struct pt_regs *regs)
 {
 	u64 pstate = regs->pstate;
@@ -227,7 +238,10 @@ static void print_pstate(struct pt_regs *regs)
 			pstate & PSR_AA32_I_BIT ? 'I' : 'i',
 			pstate & PSR_AA32_F_BIT ? 'F' : 'f');
 	} else {
-		printk("pstate: %08llx (%c%c%c%c %c%c%c%c %cPAN %cUAO)\n",
+		const char *btype_str = btypes[(pstate & PSR_BTYPE_MASK) >>
+					       PSR_BTYPE_SHIFT];
+
+		printk("pstate: %08llx (%c%c%c%c %c%c%c%c %cPAN %cUAO BTYPE=%s)\n",
 			pstate,
 			pstate & PSR_N_BIT ? 'N' : 'n',
 			pstate & PSR_Z_BIT ? 'Z' : 'z',
@@ -238,7 +252,8 @@ static void print_pstate(struct pt_regs *regs)
 			pstate & PSR_I_BIT ? 'I' : 'i',
 			pstate & PSR_F_BIT ? 'F' : 'f',
 			pstate & PSR_PAN_BIT ? '+' : '-',
-			pstate & PSR_UAO_BIT ? '+' : '-');
+			pstate & PSR_UAO_BIT ? '+' : '-',
+			btype_str);
 	}
 }
 
@@ -655,3 +670,25 @@ asmlinkage void __sched arm64_preempt_schedule_irq(void)
 	if (system_capabilities_finalized())
 		preempt_schedule_irq();
 }
+
+#ifdef CONFIG_BINFMT_ELF
+int arch_elf_adjust_prot(int prot, const struct arch_elf_state *state,
+			 bool has_interp, bool is_interp)
+{
+	/*
+	 * For dynamically linked executables the interpreter is
+	 * responsible for setting PROT_BTI on everything except
+	 * itself.
+	 */
+	if (is_interp != has_interp)
+		return prot;
+
+	if (!(state->flags & ARM64_ELF_BTI))
+		return prot;
+
+	if (prot & PROT_EXEC)
+		prot |= PROT_BTI;
+
+	return prot;
+}
+#endif
diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index e7b01904f180..76790a5f2a0d 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -1875,7 +1875,7 @@ void syscall_trace_exit(struct pt_regs *regs)
  */
 #define SPSR_EL1_AARCH64_RES0_BITS \
 	(GENMASK_ULL(63, 32) | GENMASK_ULL(27, 25) | GENMASK_ULL(23, 22) | \
-	 GENMASK_ULL(20, 13) | GENMASK_ULL(11, 10) | GENMASK_ULL(5, 5))
+	 GENMASK_ULL(20, 13) | GENMASK_ULL(5, 5))
 #define SPSR_EL1_AARCH32_RES0_BITS \
 	(GENMASK_ULL(63, 32) | GENMASK_ULL(22, 22) | GENMASK_ULL(20, 20))
 
diff --git a/arch/arm64/kernel/reloc_test_syms.S b/arch/arm64/kernel/reloc_test_syms.S
index 16a34f188f26..c50f45fa29fa 100644
--- a/arch/arm64/kernel/reloc_test_syms.S
+++ b/arch/arm64/kernel/reloc_test_syms.S
@@ -5,81 +5,81 @@
 
 #include <linux/linkage.h>
 
-ENTRY(absolute_data64)
+SYM_FUNC_START(absolute_data64)
 	ldr	x0, 0f
 	ret
 0:	.quad	sym64_abs
-ENDPROC(absolute_data64)
+SYM_FUNC_END(absolute_data64)
 
-ENTRY(absolute_data32)
+SYM_FUNC_START(absolute_data32)
 	ldr	w0, 0f
 	ret
 0:	.long	sym32_abs
-ENDPROC(absolute_data32)
+SYM_FUNC_END(absolute_data32)
 
-ENTRY(absolute_data16)
+SYM_FUNC_START(absolute_data16)
 	adr	x0, 0f
 	ldrh	w0, [x0]
 	ret
 0:	.short	sym16_abs, 0
-ENDPROC(absolute_data16)
+SYM_FUNC_END(absolute_data16)
 
-ENTRY(signed_movw)
+SYM_FUNC_START(signed_movw)
 	movz	x0, #:abs_g2_s:sym64_abs
 	movk	x0, #:abs_g1_nc:sym64_abs
 	movk	x0, #:abs_g0_nc:sym64_abs
 	ret
-ENDPROC(signed_movw)
+SYM_FUNC_END(signed_movw)
 
-ENTRY(unsigned_movw)
+SYM_FUNC_START(unsigned_movw)
 	movz	x0, #:abs_g3:sym64_abs
 	movk	x0, #:abs_g2_nc:sym64_abs
 	movk	x0, #:abs_g1_nc:sym64_abs
 	movk	x0, #:abs_g0_nc:sym64_abs
 	ret
-ENDPROC(unsigned_movw)
+SYM_FUNC_END(unsigned_movw)
 
 	.align	12
 	.space	0xff8
-ENTRY(relative_adrp)
+SYM_FUNC_START(relative_adrp)
 	adrp	x0, sym64_rel
 	add	x0, x0, #:lo12:sym64_rel
 	ret
-ENDPROC(relative_adrp)
+SYM_FUNC_END(relative_adrp)
 
 	.align	12
 	.space	0xffc
-ENTRY(relative_adrp_far)
+SYM_FUNC_START(relative_adrp_far)
 	adrp	x0, memstart_addr
 	add	x0, x0, #:lo12:memstart_addr
 	ret
-ENDPROC(relative_adrp_far)
+SYM_FUNC_END(relative_adrp_far)
 
-ENTRY(relative_adr)
+SYM_FUNC_START(relative_adr)
 	adr	x0, sym64_rel
 	ret
-ENDPROC(relative_adr)
+SYM_FUNC_END(relative_adr)
 
-ENTRY(relative_data64)
+SYM_FUNC_START(relative_data64)
 	adr	x1, 0f
 	ldr	x0, [x1]
 	add	x0, x0, x1
 	ret
 0:	.quad	sym64_rel - .
-ENDPROC(relative_data64)
+SYM_FUNC_END(relative_data64)
 
-ENTRY(relative_data32)
+SYM_FUNC_START(relative_data32)
 	adr	x1, 0f
 	ldr	w0, [x1]
 	add	x0, x0, x1
 	ret
 0:	.long	sym64_rel - .
-ENDPROC(relative_data32)
+SYM_FUNC_END(relative_data32)
 
-ENTRY(relative_data16)
+SYM_FUNC_START(relative_data16)
 	adr	x1, 0f
 	ldrsh	w0, [x1]
 	add	x0, x0, x1
 	ret
 0:	.short	sym64_rel - ., 0
-ENDPROC(relative_data16)
+SYM_FUNC_END(relative_data16)
diff --git a/arch/arm64/kernel/relocate_kernel.S b/arch/arm64/kernel/relocate_kernel.S
index c40ce496c78b..542d6edc6806 100644
--- a/arch/arm64/kernel/relocate_kernel.S
+++ b/arch/arm64/kernel/relocate_kernel.S
@@ -26,7 +26,7 @@
  * control_code_page, a special page which has been set up to be preserved
  * during the copy operation.
  */
-ENTRY(arm64_relocate_new_kernel)
+SYM_CODE_START(arm64_relocate_new_kernel)
 
 	/* Setup the list loop variables. */
 	mov	x18, x2				/* x18 = dtb address */
@@ -111,7 +111,7 @@ ENTRY(arm64_relocate_new_kernel)
 	mov	x3, xzr
 	br	x17
 
-ENDPROC(arm64_relocate_new_kernel)
+SYM_CODE_END(arm64_relocate_new_kernel)
 
 .align 3	/* To keep the 64-bit values below naturally aligned. */
 
diff --git a/arch/arm64/kernel/scs.c b/arch/arm64/kernel/scs.c
new file mode 100644
index 000000000000..e8f7ff45dd8f
--- /dev/null
+++ b/arch/arm64/kernel/scs.c
@@ -0,0 +1,16 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Shadow Call Stack support.
+ *
+ * Copyright (C) 2019 Google LLC
+ */
+
+#include <linux/percpu.h>
+#include <linux/scs.h>
+
+DEFINE_SCS(irq_shadow_call_stack);
+
+#ifdef CONFIG_ARM_SDE_INTERFACE
+DEFINE_SCS(sdei_shadow_call_stack_normal);
+DEFINE_SCS(sdei_shadow_call_stack_critical);
+#endif
diff --git a/arch/arm64/kernel/sdei.c b/arch/arm64/kernel/sdei.c
index e396e69e33a1..dab88260b137 100644
--- a/arch/arm64/kernel/sdei.c
+++ b/arch/arm64/kernel/sdei.c
@@ -95,19 +95,7 @@ static bool on_sdei_normal_stack(unsigned long sp, struct stack_info *info)
 	unsigned long low = (unsigned long)raw_cpu_read(sdei_stack_normal_ptr);
 	unsigned long high = low + SDEI_STACK_SIZE;
 
-	if (!low)
-		return false;
-
-	if (sp < low || sp >= high)
-		return false;
-
-	if (info) {
-		info->low = low;
-		info->high = high;
-		info->type = STACK_TYPE_SDEI_NORMAL;
-	}
-
-	return true;
+	return on_stack(sp, low, high, STACK_TYPE_SDEI_NORMAL, info);
 }
 
 static bool on_sdei_critical_stack(unsigned long sp, struct stack_info *info)
@@ -115,19 +103,7 @@ static bool on_sdei_critical_stack(unsigned long sp, struct stack_info *info)
 	unsigned long low = (unsigned long)raw_cpu_read(sdei_stack_critical_ptr);
 	unsigned long high = low + SDEI_STACK_SIZE;
 
-	if (!low)
-		return false;
-
-	if (sp < low || sp >= high)
-		return false;
-
-	if (info) {
-		info->low = low;
-		info->high = high;
-		info->type = STACK_TYPE_SDEI_CRITICAL;
-	}
-
-	return true;
+	return on_stack(sp, low, high, STACK_TYPE_SDEI_CRITICAL, info);
 }
 
 bool _on_sdei_stack(unsigned long sp, struct stack_info *info)
diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
index 339882db5a91..801d56cdf701 100644
--- a/arch/arm64/kernel/signal.c
+++ b/arch/arm64/kernel/signal.c
@@ -732,6 +732,22 @@ static void setup_return(struct pt_regs *regs, struct k_sigaction *ka,
 	regs->regs[29] = (unsigned long)&user->next_frame->fp;
 	regs->pc = (unsigned long)ka->sa.sa_handler;
 
+	/*
+	 * Signal delivery is a (wacky) indirect function call in
+	 * userspace, so simulate the same setting of BTYPE as a BLR
+	 * <register containing the signal handler entry point>.
+	 * Signal delivery to a location in a PROT_BTI guarded page
+	 * that is not a function entry point will now trigger a
+	 * SIGILL in userspace.
+	 *
+	 * If the signal handler entry point is not in a PROT_BTI
+	 * guarded page, this is harmless.
+	 */
+	if (system_supports_bti()) {
+		regs->pstate &= ~PSR_BTYPE_MASK;
+		regs->pstate |= PSR_BTYPE_C;
+	}
+
 	if (ka->sa.sa_flags & SA_RESTORER)
 		sigtramp = ka->sa.sa_restorer;
 	else
diff --git a/arch/arm64/kernel/sleep.S b/arch/arm64/kernel/sleep.S
index 7b2f2e650c44..ba40d57757d6 100644
--- a/arch/arm64/kernel/sleep.S
+++ b/arch/arm64/kernel/sleep.S
@@ -62,7 +62,7 @@
  *
  *  x0 = struct sleep_stack_data area
  */
-ENTRY(__cpu_suspend_enter)
+SYM_FUNC_START(__cpu_suspend_enter)
 	stp	x29, lr, [x0, #SLEEP_STACK_DATA_CALLEE_REGS]
 	stp	x19, x20, [x0,#SLEEP_STACK_DATA_CALLEE_REGS+16]
 	stp	x21, x22, [x0,#SLEEP_STACK_DATA_CALLEE_REGS+32]
@@ -95,23 +95,22 @@ ENTRY(__cpu_suspend_enter)
 	ldp	x29, lr, [sp], #16
 	mov	x0, #1
 	ret
-ENDPROC(__cpu_suspend_enter)
+SYM_FUNC_END(__cpu_suspend_enter)
 
 	.pushsection ".idmap.text", "awx"
-ENTRY(cpu_resume)
+SYM_CODE_START(cpu_resume)
 	bl	el2_setup		// if in EL2 drop to EL1 cleanly
-	mov	x0, #ARM64_CPU_RUNTIME
 	bl	__cpu_setup
 	/* enable the MMU early - so we can access sleep_save_stash by va */
 	adrp	x1, swapper_pg_dir
 	bl	__enable_mmu
 	ldr	x8, =_cpu_resume
 	br	x8
-ENDPROC(cpu_resume)
+SYM_CODE_END(cpu_resume)
 	.ltorg
 	.popsection
 
-ENTRY(_cpu_resume)
+SYM_FUNC_START(_cpu_resume)
 	mrs	x1, mpidr_el1
 	adr_l	x8, mpidr_hash		// x8 = struct mpidr_hash virt address
 
@@ -147,4 +146,4 @@ ENTRY(_cpu_resume)
 	ldp	x29, lr, [x29]
 	mov	x0, #0
 	ret
-ENDPROC(_cpu_resume)
+SYM_FUNC_END(_cpu_resume)
diff --git a/arch/arm64/kernel/smccc-call.S b/arch/arm64/kernel/smccc-call.S
index 54655273d1e0..1f93809528a4 100644
--- a/arch/arm64/kernel/smccc-call.S
+++ b/arch/arm64/kernel/smccc-call.S
@@ -30,9 +30,9 @@
  *		  unsigned long a6, unsigned long a7, struct arm_smccc_res *res,
  *		  struct arm_smccc_quirk *quirk)
  */
-ENTRY(__arm_smccc_smc)
+SYM_FUNC_START(__arm_smccc_smc)
 	SMCCC	smc
-ENDPROC(__arm_smccc_smc)
+SYM_FUNC_END(__arm_smccc_smc)
 EXPORT_SYMBOL(__arm_smccc_smc)
 
 /*
@@ -41,7 +41,7 @@ EXPORT_SYMBOL(__arm_smccc_smc)
  *		  unsigned long a6, unsigned long a7, struct arm_smccc_res *res,
  *		  struct arm_smccc_quirk *quirk)
  */
-ENTRY(__arm_smccc_hvc)
+SYM_FUNC_START(__arm_smccc_hvc)
 	SMCCC	hvc
-ENDPROC(__arm_smccc_hvc)
+SYM_FUNC_END(__arm_smccc_hvc)
 EXPORT_SYMBOL(__arm_smccc_hvc)
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index bb813d06114a..04b1ca0d7aba 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -65,7 +65,7 @@ EXPORT_PER_CPU_SYMBOL(cpu_number);
  */
 struct secondary_data secondary_data;
 /* Number of CPUs which aren't online, but looping in kernel text. */
-int cpus_stuck_in_kernel;
+static int cpus_stuck_in_kernel;
 
 enum ipi_msg_type {
 	IPI_RESCHEDULE,
@@ -114,10 +114,6 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle)
 	 */
 	secondary_data.task = idle;
 	secondary_data.stack = task_stack_page(idle) + THREAD_SIZE;
-#if defined(CONFIG_ARM64_PTR_AUTH)
-	secondary_data.ptrauth_key.apia.lo = idle->thread.keys_kernel.apia.lo;
-	secondary_data.ptrauth_key.apia.hi = idle->thread.keys_kernel.apia.hi;
-#endif
 	update_cpu_boot_status(CPU_MMU_OFF);
 	__flush_dcache_area(&secondary_data, sizeof(secondary_data));
 
@@ -140,10 +136,6 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle)
 	pr_crit("CPU%u: failed to come online\n", cpu);
 	secondary_data.task = NULL;
 	secondary_data.stack = NULL;
-#if defined(CONFIG_ARM64_PTR_AUTH)
-	secondary_data.ptrauth_key.apia.lo = 0;
-	secondary_data.ptrauth_key.apia.hi = 0;
-#endif
 	__flush_dcache_area(&secondary_data, sizeof(secondary_data));
 	status = READ_ONCE(secondary_data.status);
 	if (status == CPU_MMU_OFF)
diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c
index a12c0c88d345..5f5b868292f5 100644
--- a/arch/arm64/kernel/syscall.c
+++ b/arch/arm64/kernel/syscall.c
@@ -98,6 +98,24 @@ static void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr,
 	regs->orig_x0 = regs->regs[0];
 	regs->syscallno = scno;
 
+	/*
+	 * BTI note:
+	 * The architecture does not guarantee that SPSR.BTYPE is zero
+	 * on taking an SVC, so we could return to userspace with a
+	 * non-zero BTYPE after the syscall.
+	 *
+	 * This shouldn't matter except when userspace is explicitly
+	 * doing something stupid, such as setting PROT_BTI on a page
+	 * that lacks conforming BTI/PACIxSP instructions, falling
+	 * through from one executable page to another with differing
+	 * PROT_BTI, or messing with BTYPE via ptrace: in such cases,
+	 * userspace should not be surprised if a SIGILL occurs on
+	 * syscall return.
+	 *
+	 * So, don't touch regs->pstate & PSR_BTYPE_MASK here.
+	 * (Similarly for HVC and SMC elsewhere.)
+	 */
+
 	cortex_a76_erratum_1463225_svc_handler();
 	local_daif_restore(DAIF_PROCCTX);
 	user_exit();
diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index c728f163f329..d332590f5978 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -272,6 +272,61 @@ void arm64_notify_die(const char *str, struct pt_regs *regs,
 	}
 }
 
+#ifdef CONFIG_COMPAT
+#define PSTATE_IT_1_0_SHIFT	25
+#define PSTATE_IT_1_0_MASK	(0x3 << PSTATE_IT_1_0_SHIFT)
+#define PSTATE_IT_7_2_SHIFT	10
+#define PSTATE_IT_7_2_MASK	(0x3f << PSTATE_IT_7_2_SHIFT)
+
+static u32 compat_get_it_state(struct pt_regs *regs)
+{
+	u32 it, pstate = regs->pstate;
+
+	it  = (pstate & PSTATE_IT_1_0_MASK) >> PSTATE_IT_1_0_SHIFT;
+	it |= ((pstate & PSTATE_IT_7_2_MASK) >> PSTATE_IT_7_2_SHIFT) << 2;
+
+	return it;
+}
+
+static void compat_set_it_state(struct pt_regs *regs, u32 it)
+{
+	u32 pstate_it;
+
+	pstate_it  = (it << PSTATE_IT_1_0_SHIFT) & PSTATE_IT_1_0_MASK;
+	pstate_it |= ((it >> 2) << PSTATE_IT_7_2_SHIFT) & PSTATE_IT_7_2_MASK;
+
+	regs->pstate &= ~PSR_AA32_IT_MASK;
+	regs->pstate |= pstate_it;
+}
+
+static void advance_itstate(struct pt_regs *regs)
+{
+	u32 it;
+
+	/* ARM mode */
+	if (!(regs->pstate & PSR_AA32_T_BIT) ||
+	    !(regs->pstate & PSR_AA32_IT_MASK))
+		return;
+
+	it  = compat_get_it_state(regs);
+
+	/*
+	 * If this is the last instruction of the block, wipe the IT
+	 * state. Otherwise advance it.
+	 */
+	if (!(it & 7))
+		it = 0;
+	else
+		it = (it & 0xe0) | ((it << 1) & 0x1f);
+
+	compat_set_it_state(regs, it);
+}
+#else
+static void advance_itstate(struct pt_regs *regs)
+{
+}
+#endif
+
 void arm64_skip_faulting_instruction(struct pt_regs *regs, unsigned long size)
 {
 	regs->pc += size;
@@ -282,6 +337,11 @@ void arm64_skip_faulting_instruction(struct pt_regs *regs, unsigned long size)
 	 */
 	if (user_mode(regs))
 		user_fastforward_single_step(current);
+
+	if (compat_user_mode(regs))
+		advance_itstate(regs);
+	else
+		regs->pstate &= ~PSR_BTYPE_MASK;
 }
 
 static LIST_HEAD(undef_hook);
@@ -411,6 +471,13 @@ void do_undefinstr(struct pt_regs *regs)
 }
 NOKPROBE_SYMBOL(do_undefinstr);
 
+void do_bti(struct pt_regs *regs)
+{
+	BUG_ON(!user_mode(regs));
+	force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc);
+}
+NOKPROBE_SYMBOL(do_bti);
+
 #define __user_cache_maint(insn, address, res)			\
 	if (address >= user_addr_max()) {			\
 		res = -EFAULT;					\
@@ -566,34 +633,7 @@ static const struct sys64_hook sys64_hooks[] = {
 	{},
 };
 
-
 #ifdef CONFIG_COMPAT
-#define PSTATE_IT_1_0_SHIFT	25
-#define PSTATE_IT_1_0_MASK	(0x3 << PSTATE_IT_1_0_SHIFT)
-#define PSTATE_IT_7_2_SHIFT	10
-#define PSTATE_IT_7_2_MASK	(0x3f << PSTATE_IT_7_2_SHIFT)
-
-static u32 compat_get_it_state(struct pt_regs *regs)
-{
-	u32 it, pstate = regs->pstate;
-
-	it  = (pstate & PSTATE_IT_1_0_MASK) >> PSTATE_IT_1_0_SHIFT;
-	it |= ((pstate & PSTATE_IT_7_2_MASK) >> PSTATE_IT_7_2_SHIFT) << 2;
-
-	return it;
-}
-
-static void compat_set_it_state(struct pt_regs *regs, u32 it)
-{
-	u32 pstate_it;
-
-	pstate_it  = (it << PSTATE_IT_1_0_SHIFT) & PSTATE_IT_1_0_MASK;
-	pstate_it |= ((it >> 2) << PSTATE_IT_7_2_SHIFT) & PSTATE_IT_7_2_MASK;
-
-	regs->pstate &= ~PSR_AA32_IT_MASK;
-	regs->pstate |= pstate_it;
-}
-
 static bool cp15_cond_valid(unsigned int esr, struct pt_regs *regs)
 {
 	int cond;
@@ -614,42 +654,12 @@ static bool cp15_cond_valid(unsigned int esr, struct pt_regs *regs)
 	return aarch32_opcode_cond_checks[cond](regs->pstate);
 }
 
-static void advance_itstate(struct pt_regs *regs)
-{
-	u32 it;
-
-	/* ARM mode */
-	if (!(regs->pstate & PSR_AA32_T_BIT) ||
-	    !(regs->pstate & PSR_AA32_IT_MASK))
-		return;
-
-	it  = compat_get_it_state(regs);
-
-	/*
-	 * If this is the last instruction of the block, wipe the IT
-	 * state. Otherwise advance it.
-	 */
-	if (!(it & 7))
-		it = 0;
-	else
-		it = (it & 0xe0) | ((it << 1) & 0x1f);
-
-	compat_set_it_state(regs, it);
-}
-
-static void arm64_compat_skip_faulting_instruction(struct pt_regs *regs,
-						   unsigned int sz)
-{
-	advance_itstate(regs);
-	arm64_skip_faulting_instruction(regs, sz);
-}
-
 static void compat_cntfrq_read_handler(unsigned int esr, struct pt_regs *regs)
 {
 	int reg = (esr & ESR_ELx_CP15_32_ISS_RT_MASK) >> ESR_ELx_CP15_32_ISS_RT_SHIFT;
 
 	pt_regs_write_reg(regs, reg, arch_timer_get_rate());
-	arm64_compat_skip_faulting_instruction(regs, 4);
+	arm64_skip_faulting_instruction(regs, 4);
 }
 
 static const struct sys64_hook cp15_32_hooks[] = {
@@ -669,7 +679,7 @@ static void compat_cntvct_read_handler(unsigned int esr, struct pt_regs *regs)
 
 	pt_regs_write_reg(regs, rt, lower_32_bits(val));
 	pt_regs_write_reg(regs, rt2, upper_32_bits(val));
-	arm64_compat_skip_faulting_instruction(regs, 4);
+	arm64_skip_faulting_instruction(regs, 4);
 }
 
 static const struct sys64_hook cp15_64_hooks[] = {
@@ -690,7 +700,7 @@ void do_cp15instr(unsigned int esr, struct pt_regs *regs)
 		 * There is no T16 variant of a CP access, so we
 		 * always advance PC by 4 bytes.
 		 */
-		arm64_compat_skip_faulting_instruction(regs, 4);
+		arm64_skip_faulting_instruction(regs, 4);
 		return;
 	}
 
@@ -753,6 +763,7 @@ static const char *esr_class_str[] = {
 	[ESR_ELx_EC_CP10_ID]		= "CP10 MRC/VMRS",
 	[ESR_ELx_EC_PAC]		= "PAC",
 	[ESR_ELx_EC_CP14_64]		= "CP14 MCRR/MRRC",
+	[ESR_ELx_EC_BTI]		= "BTI",
 	[ESR_ELx_EC_ILL]		= "PSTATE.IL",
 	[ESR_ELx_EC_SVC32]		= "SVC (AArch32)",
 	[ESR_ELx_EC_HVC32]		= "HVC (AArch32)",
@@ -1043,11 +1054,11 @@ int __init early_brk64(unsigned long addr, unsigned int esr,
 	return bug_handler(regs, esr) != DBG_HOOK_HANDLED;
 }
 
-/* This registration must happen early, before debug_traps_init(). */
 void __init trap_init(void)
 {
 	register_kernel_break_hook(&bug_break_hook);
 #ifdef CONFIG_KASAN_SW_TAGS
 	register_kernel_break_hook(&kasan_break_hook);
 #endif
+	debug_traps_init();
 }
diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
index 033a48f30dbb..d51a898fd60f 100644
--- a/arch/arm64/kernel/vdso.c
+++ b/arch/arm64/kernel/vdso.c
@@ -33,20 +33,14 @@ extern char vdso_start[], vdso_end[];
 extern char vdso32_start[], vdso32_end[];
 #endif /* CONFIG_COMPAT_VDSO */
 
-/* vdso_lookup arch_index */
-enum arch_vdso_type {
-	ARM64_VDSO = 0,
+enum vdso_abi {
+	VDSO_ABI_AA64,
 #ifdef CONFIG_COMPAT_VDSO
-	ARM64_VDSO32 = 1,
+	VDSO_ABI_AA32,
 #endif /* CONFIG_COMPAT_VDSO */
 };
-#ifdef CONFIG_COMPAT_VDSO
-#define VDSO_TYPES		(ARM64_VDSO32 + 1)
-#else
-#define VDSO_TYPES		(ARM64_VDSO + 1)
-#endif /* CONFIG_COMPAT_VDSO */
 
-struct __vdso_abi {
+struct vdso_abi_info {
 	const char *name;
 	const char *vdso_code_start;
 	const char *vdso_code_end;
@@ -57,14 +51,14 @@ struct __vdso_abi {
 	struct vm_special_mapping *cm;
 };
 
-static struct __vdso_abi vdso_lookup[VDSO_TYPES] __ro_after_init = {
-	{
+static struct vdso_abi_info vdso_info[] __ro_after_init = {
+	[VDSO_ABI_AA64] = {
 		.name = "vdso",
 		.vdso_code_start = vdso_start,
 		.vdso_code_end = vdso_end,
 	},
 #ifdef CONFIG_COMPAT_VDSO
-	{
+	[VDSO_ABI_AA32] = {
 		.name = "vdso32",
 		.vdso_code_start = vdso32_start,
 		.vdso_code_end = vdso32_end,
@@ -81,13 +75,13 @@ static union {
 } vdso_data_store __page_aligned_data;
 struct vdso_data *vdso_data = vdso_data_store.data;
 
-static int __vdso_remap(enum arch_vdso_type arch_index,
+static int __vdso_remap(enum vdso_abi abi,
 			const struct vm_special_mapping *sm,
 			struct vm_area_struct *new_vma)
 {
 	unsigned long new_size = new_vma->vm_end - new_vma->vm_start;
-	unsigned long vdso_size = vdso_lookup[arch_index].vdso_code_end -
-				  vdso_lookup[arch_index].vdso_code_start;
+	unsigned long vdso_size = vdso_info[abi].vdso_code_end -
+				  vdso_info[abi].vdso_code_start;
 
 	if (vdso_size != new_size)
 		return -EINVAL;
@@ -97,24 +91,24 @@ static int __vdso_remap(enum arch_vdso_type arch_index,
 	return 0;
 }
 
-static int __vdso_init(enum arch_vdso_type arch_index)
+static int __vdso_init(enum vdso_abi abi)
 {
 	int i;
 	struct page **vdso_pagelist;
 	unsigned long pfn;
 
-	if (memcmp(vdso_lookup[arch_index].vdso_code_start, "\177ELF", 4)) {
+	if (memcmp(vdso_info[abi].vdso_code_start, "\177ELF", 4)) {
 		pr_err("vDSO is not a valid ELF object!\n");
 		return -EINVAL;
 	}
 
-	vdso_lookup[arch_index].vdso_pages = (
-			vdso_lookup[arch_index].vdso_code_end -
-			vdso_lookup[arch_index].vdso_code_start) >>
+	vdso_info[abi].vdso_pages = (
+			vdso_info[abi].vdso_code_end -
+			vdso_info[abi].vdso_code_start) >>
 			PAGE_SHIFT;
 
 	/* Allocate the vDSO pagelist, plus a page for the data. */
-	vdso_pagelist = kcalloc(vdso_lookup[arch_index].vdso_pages + 1,
+	vdso_pagelist = kcalloc(vdso_info[abi].vdso_pages + 1,
 				sizeof(struct page *),
 				GFP_KERNEL);
 	if (vdso_pagelist == NULL)
@@ -125,26 +119,27 @@ static int __vdso_init(enum arch_vdso_type arch_index)
 
 
 	/* Grab the vDSO code pages. */
-	pfn = sym_to_pfn(vdso_lookup[arch_index].vdso_code_start);
+	pfn = sym_to_pfn(vdso_info[abi].vdso_code_start);
 
-	for (i = 0; i < vdso_lookup[arch_index].vdso_pages; i++)
+	for (i = 0; i < vdso_info[abi].vdso_pages; i++)
 		vdso_pagelist[i + 1] = pfn_to_page(pfn + i);
 
-	vdso_lookup[arch_index].dm->pages = &vdso_pagelist[0];
-	vdso_lookup[arch_index].cm->pages = &vdso_pagelist[1];
+	vdso_info[abi].dm->pages = &vdso_pagelist[0];
+	vdso_info[abi].cm->pages = &vdso_pagelist[1];
 
 	return 0;
 }
 
-static int __setup_additional_pages(enum arch_vdso_type arch_index,
+static int __setup_additional_pages(enum vdso_abi abi,
 				    struct mm_struct *mm,
 				    struct linux_binprm *bprm,
 				    int uses_interp)
 {
 	unsigned long vdso_base, vdso_text_len, vdso_mapping_len;
+	unsigned long gp_flags = 0;
 	void *ret;
 
-	vdso_text_len = vdso_lookup[arch_index].vdso_pages << PAGE_SHIFT;
+	vdso_text_len = vdso_info[abi].vdso_pages << PAGE_SHIFT;
 	/* Be sure to map the data page */
 	vdso_mapping_len = vdso_text_len + PAGE_SIZE;
 
@@ -156,16 +151,19 @@ static int __setup_additional_pages(enum arch_vdso_type arch_index,
 
 	ret = _install_special_mapping(mm, vdso_base, PAGE_SIZE,
 				       VM_READ|VM_MAYREAD,
-				       vdso_lookup[arch_index].dm);
+				       vdso_info[abi].dm);
 	if (IS_ERR(ret))
 		goto up_fail;
 
+	if (IS_ENABLED(CONFIG_ARM64_BTI_KERNEL) && system_supports_bti())
+		gp_flags = VM_ARM64_BTI;
+
 	vdso_base += PAGE_SIZE;
 	mm->context.vdso = (void *)vdso_base;
 	ret = _install_special_mapping(mm, vdso_base, vdso_text_len,
-				       VM_READ|VM_EXEC|
+				       VM_READ|VM_EXEC|gp_flags|
 				       VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
-				       vdso_lookup[arch_index].cm);
+				       vdso_info[abi].cm);
 	if (IS_ERR(ret))
 		goto up_fail;
 
@@ -184,46 +182,42 @@ up_fail:
 static int aarch32_vdso_mremap(const struct vm_special_mapping *sm,
 		struct vm_area_struct *new_vma)
 {
-	return __vdso_remap(ARM64_VDSO32, sm, new_vma);
+	return __vdso_remap(VDSO_ABI_AA32, sm, new_vma);
 }
 #endif /* CONFIG_COMPAT_VDSO */
 
-/*
- * aarch32_vdso_pages:
- * 0 - kuser helpers
- * 1 - sigreturn code
- * or (CONFIG_COMPAT_VDSO):
- * 0 - kuser helpers
- * 1 - vdso data
- * 2 - vdso code
- */
-#define C_VECTORS	0
+enum aarch32_map {
+	AA32_MAP_VECTORS, /* kuser helpers */
 #ifdef CONFIG_COMPAT_VDSO
-#define C_VVAR		1
-#define C_VDSO		2
-#define C_PAGES		(C_VDSO + 1)
+	AA32_MAP_VVAR,
+	AA32_MAP_VDSO,
 #else
-#define C_SIGPAGE	1
-#define C_PAGES		(C_SIGPAGE + 1)
-#endif /* CONFIG_COMPAT_VDSO */
-static struct page *aarch32_vdso_pages[C_PAGES] __ro_after_init;
-static struct vm_special_mapping aarch32_vdso_spec[C_PAGES] = {
-	{
+	AA32_MAP_SIGPAGE
+#endif
+};
+
+static struct page *aarch32_vectors_page __ro_after_init;
+#ifndef CONFIG_COMPAT_VDSO
+static struct page *aarch32_sig_page __ro_after_init;
+#endif
+
+static struct vm_special_mapping aarch32_vdso_maps[] = {
+	[AA32_MAP_VECTORS] = {
 		.name	= "[vectors]", /* ABI */
-		.pages	= &aarch32_vdso_pages[C_VECTORS],
+		.pages	= &aarch32_vectors_page,
 	},
 #ifdef CONFIG_COMPAT_VDSO
-	{
+	[AA32_MAP_VVAR] = {
 		.name = "[vvar]",
 	},
-	{
+	[AA32_MAP_VDSO] = {
 		.name = "[vdso]",
 		.mremap = aarch32_vdso_mremap,
 	},
 #else
-	{
+	[AA32_MAP_SIGPAGE] = {
 		.name	= "[sigpage]", /* ABI */
-		.pages	= &aarch32_vdso_pages[C_SIGPAGE],
+		.pages	= &aarch32_sig_page,
 	},
 #endif /* CONFIG_COMPAT_VDSO */
 };
@@ -243,8 +237,8 @@ static int aarch32_alloc_kuser_vdso_page(void)
 
 	memcpy((void *)(vdso_page + 0x1000 - kuser_sz), __kuser_helper_start,
 	       kuser_sz);
-	aarch32_vdso_pages[C_VECTORS] = virt_to_page(vdso_page);
-	flush_dcache_page(aarch32_vdso_pages[C_VECTORS]);
+	aarch32_vectors_page = virt_to_page(vdso_page);
+	flush_dcache_page(aarch32_vectors_page);
 	return 0;
 }
 
@@ -253,10 +247,10 @@ static int __aarch32_alloc_vdso_pages(void)
 {
 	int ret;
 
-	vdso_lookup[ARM64_VDSO32].dm = &aarch32_vdso_spec[C_VVAR];
-	vdso_lookup[ARM64_VDSO32].cm = &aarch32_vdso_spec[C_VDSO];
+	vdso_info[VDSO_ABI_AA32].dm = &aarch32_vdso_maps[AA32_MAP_VVAR];
+	vdso_info[VDSO_ABI_AA32].cm = &aarch32_vdso_maps[AA32_MAP_VDSO];
 
-	ret = __vdso_init(ARM64_VDSO32);
+	ret = __vdso_init(VDSO_ABI_AA32);
 	if (ret)
 		return ret;
 
@@ -275,8 +269,8 @@ static int __aarch32_alloc_vdso_pages(void)
 		return -ENOMEM;
 
 	memcpy((void *)sigpage, __aarch32_sigret_code_start, sigret_sz);
-	aarch32_vdso_pages[C_SIGPAGE] = virt_to_page(sigpage);
-	flush_dcache_page(aarch32_vdso_pages[C_SIGPAGE]);
+	aarch32_sig_page = virt_to_page(sigpage);
+	flush_dcache_page(aarch32_sig_page);
 
 	ret = aarch32_alloc_kuser_vdso_page();
 	if (ret)
@@ -306,7 +300,7 @@ static int aarch32_kuser_helpers_setup(struct mm_struct *mm)
 	ret = _install_special_mapping(mm, AARCH32_VECTORS_BASE, PAGE_SIZE,
 				       VM_READ | VM_EXEC |
 				       VM_MAYREAD | VM_MAYEXEC,
-				       &aarch32_vdso_spec[C_VECTORS]);
+				       &aarch32_vdso_maps[AA32_MAP_VECTORS]);
 
 	return PTR_ERR_OR_ZERO(ret);
 }
@@ -330,7 +324,7 @@ static int aarch32_sigreturn_setup(struct mm_struct *mm)
 	ret = _install_special_mapping(mm, addr, PAGE_SIZE,
 				       VM_READ | VM_EXEC | VM_MAYREAD |
 				       VM_MAYWRITE | VM_MAYEXEC,
-				       &aarch32_vdso_spec[C_SIGPAGE]);
+				       &aarch32_vdso_maps[AA32_MAP_SIGPAGE]);
 	if (IS_ERR(ret))
 		goto out;
 
@@ -354,7 +348,7 @@ int aarch32_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 		goto out;
 
 #ifdef CONFIG_COMPAT_VDSO
-	ret = __setup_additional_pages(ARM64_VDSO32,
+	ret = __setup_additional_pages(VDSO_ABI_AA32,
 				       mm,
 				       bprm,
 				       uses_interp);
@@ -371,22 +365,19 @@ out:
 static int vdso_mremap(const struct vm_special_mapping *sm,
 		struct vm_area_struct *new_vma)
 {
-	return __vdso_remap(ARM64_VDSO, sm, new_vma);
+	return __vdso_remap(VDSO_ABI_AA64, sm, new_vma);
 }
 
-/*
- * aarch64_vdso_pages:
- * 0 - vvar
- * 1 - vdso
- */
-#define A_VVAR		0
-#define A_VDSO		1
-#define A_PAGES		(A_VDSO + 1)
-static struct vm_special_mapping vdso_spec[A_PAGES] __ro_after_init = {
-	{
+enum aarch64_map {
+	AA64_MAP_VVAR,
+	AA64_MAP_VDSO,
+};
+
+static struct vm_special_mapping aarch64_vdso_maps[] __ro_after_init = {
+	[AA64_MAP_VVAR] = {
 		.name	= "[vvar]",
 	},
-	{
+	[AA64_MAP_VDSO] = {
 		.name	= "[vdso]",
 		.mremap = vdso_mremap,
 	},
@@ -394,10 +385,10 @@ static struct vm_special_mapping vdso_spec[A_PAGES] __ro_after_init = {
 
 static int __init vdso_init(void)
 {
-	vdso_lookup[ARM64_VDSO].dm = &vdso_spec[A_VVAR];
-	vdso_lookup[ARM64_VDSO].cm = &vdso_spec[A_VDSO];
+	vdso_info[VDSO_ABI_AA64].dm = &aarch64_vdso_maps[AA64_MAP_VVAR];
+	vdso_info[VDSO_ABI_AA64].cm = &aarch64_vdso_maps[AA64_MAP_VDSO];
 
-	return __vdso_init(ARM64_VDSO);
+	return __vdso_init(VDSO_ABI_AA64);
 }
 arch_initcall(vdso_init);
 
@@ -410,7 +401,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm,
 	if (down_write_killable(&mm->mmap_sem))
 		return -EINTR;
 
-	ret = __setup_additional_pages(ARM64_VDSO,
+	ret = __setup_additional_pages(VDSO_ABI_AA64,
 				       mm,
 				       bprm,
 				       uses_interp);
diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile
index 3862cad2410c..556d424c6f52 100644
--- a/arch/arm64/kernel/vdso/Makefile
+++ b/arch/arm64/kernel/vdso/Makefile
@@ -17,15 +17,19 @@ obj-vdso := vgettimeofday.o note.o sigreturn.o
 targets := $(obj-vdso) vdso.so vdso.so.dbg
 obj-vdso := $(addprefix $(obj)/, $(obj-vdso))
 
+btildflags-$(CONFIG_ARM64_BTI_KERNEL) += -z force-bti
+
+# -Bsymbolic has been added for consistency with arm, the compat vDSO and
+# potential future proofing if we end up with internal calls to the exported
+# routines, as x86 does (see 6f121e548f83 ("x86, vdso: Reimplement vdso.so
+# preparation in build-time C")).
 ldflags-y := -shared -nostdlib -soname=linux-vdso.so.1 --hash-style=sysv \
-		--build-id -n -T
+		-Bsymbolic --eh-frame-hdr --build-id -n $(btildflags-y) -T
 
 ccflags-y := -fno-common -fno-builtin -fno-stack-protector -ffixed-x18
 ccflags-y += -DDISABLE_BRANCH_PROFILING
 
-VDSO_LDFLAGS := -Bsymbolic
-
-CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os
+CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS)
 KBUILD_CFLAGS			+= $(DISABLE_LTO)
 KASAN_SANITIZE			:= n
 UBSAN_SANITIZE			:= n
diff --git a/arch/arm64/kernel/vdso/note.S b/arch/arm64/kernel/vdso/note.S
index 0ce6ec75a525..3d4e82290c80 100644
--- a/arch/arm64/kernel/vdso/note.S
+++ b/arch/arm64/kernel/vdso/note.S
@@ -12,9 +12,12 @@
 #include <linux/version.h>
 #include <linux/elfnote.h>
 #include <linux/build-salt.h>
+#include <asm/assembler.h>
 
 ELFNOTE_START(Linux, 0, "a")
 	.long LINUX_VERSION_CODE
 ELFNOTE_END
 
 BUILD_SALT
+
+emit_aarch64_feature_1_and
diff --git a/arch/arm64/kernel/vdso/sigreturn.S b/arch/arm64/kernel/vdso/sigreturn.S
index 12324863d5c2..620a3ef837b7 100644
--- a/arch/arm64/kernel/vdso/sigreturn.S
+++ b/arch/arm64/kernel/vdso/sigreturn.S
@@ -1,7 +1,11 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 /*
  * Sigreturn trampoline for returning from a signal when the SA_RESTORER
- * flag is not set.
+ * flag is not set. It serves primarily as a hall of shame for crappy
+ * unwinders and features an exciting but mysterious NOP instruction.
+ *
+ * It's also fragile as hell, so please think twice before changing anything
+ * in here.
  *
  * Copyright (C) 2012 ARM Limited
  *
@@ -9,18 +13,54 @@
  */
 
 #include <linux/linkage.h>
+#include <asm/assembler.h>
 #include <asm/unistd.h>
 
 	.text
 
-	nop
-SYM_FUNC_START(__kernel_rt_sigreturn)
+/* Ensure that the mysterious NOP can be associated with a function. */
 	.cfi_startproc
+
+/*
+ * .cfi_signal_frame causes the corresponding Frame Description Entry in the
+ * .eh_frame section to be annotated as a signal frame. This allows DWARF
+ * unwinders (e.g. libstdc++) to implement _Unwind_GetIPInfo(), which permits
+ * unwinding out of the signal trampoline without the need for the mysterious
+ * NOP.
+ */
 	.cfi_signal_frame
-	.cfi_def_cfa	x29, 0
-	.cfi_offset	x29, 0 * 8
-	.cfi_offset	x30, 1 * 8
+
+/*
+ * Tell the unwinder where to locate the frame record linking back to the
+ * interrupted context. We don't provide unwind info for registers other
+ * than the frame pointer and the link register here; in practice, this
+ * is sufficient for unwinding in C/C++ based runtimes and the values in
+ * the sigcontext may have been modified by this point anyway. Debuggers
+ * already have baked-in strategies for attempting to unwind out of signals.
+ */
+	.cfi_def_cfa    x29, 0
+	.cfi_offset     x29, 0 * 8
+	.cfi_offset     x30, 1 * 8
+
+/*
+ * This mysterious NOP is required for some unwinders (e.g. libc++) that
+ * unconditionally subtract one from the result of _Unwind_GetIP() in order to
+ * identify the calling function.
+ * Hack borrowed from arch/powerpc/kernel/vdso64/sigtramp.S.
+ */
+	nop	// Mysterious NOP
+
+/*
+ * GDB relies on being able to identify the sigreturn instruction sequence to
+ * unwind from signal handlers. We cannot, therefore, use SYM_FUNC_START()
+ * here, as it will emit a BTI C instruction and break the unwinder. Thankfully,
+ * this function is only ever called from a RET and so omitting the landing pad
+ * is perfectly fine.
+ */
+SYM_CODE_START(__kernel_rt_sigreturn)
 	mov	x8, #__NR_rt_sigreturn
 	svc	#0
 	.cfi_endproc
-SYM_FUNC_END(__kernel_rt_sigreturn)
+SYM_CODE_END(__kernel_rt_sigreturn)
+
+emit_aarch64_feature_1_and
diff --git a/arch/arm64/kernel/vdso/vdso.S b/arch/arm64/kernel/vdso/vdso.S
index d1414fee5274..c4b1990bf2be 100644
--- a/arch/arm64/kernel/vdso/vdso.S
+++ b/arch/arm64/kernel/vdso/vdso.S
@@ -8,6 +8,7 @@
 #include <linux/init.h>
 #include <linux/linkage.h>
 #include <linux/const.h>
+#include <asm/assembler.h>
 #include <asm/page.h>
 
 	.globl vdso_start, vdso_end
@@ -19,3 +20,5 @@ vdso_start:
 vdso_end:
 
 	.previous
+
+emit_aarch64_feature_1_and
diff --git a/arch/arm64/kernel/vdso32/sigreturn.S b/arch/arm64/kernel/vdso32/sigreturn.S
index 620524969696..b0091064c3d6 100644
--- a/arch/arm64/kernel/vdso32/sigreturn.S
+++ b/arch/arm64/kernel/vdso32/sigreturn.S
@@ -3,6 +3,9 @@
  * This file provides both A32 and T32 versions, in accordance with the
  * arm sigreturn code.
  *
+ * Please read the comments in arch/arm64/kernel/vdso/sigreturn.S to
+ * understand some of the craziness in here.
+ *
  * Copyright (C) 2018 ARM Limited
  */
 
@@ -17,39 +20,39 @@
 	.save {r0-r15}
 	.pad #COMPAT_SIGFRAME_REGS_OFFSET
 	nop
-SYM_FUNC_START(__kernel_sigreturn_arm)
+SYM_CODE_START(__kernel_sigreturn_arm)
 	mov r7, #__NR_compat_sigreturn
 	svc #0
 	.fnend
-SYM_FUNC_END(__kernel_sigreturn_arm)
+SYM_CODE_END(__kernel_sigreturn_arm)
 
 	.fnstart
 	.save {r0-r15}
 	.pad #COMPAT_RT_SIGFRAME_REGS_OFFSET
 	nop
-SYM_FUNC_START(__kernel_rt_sigreturn_arm)
+SYM_CODE_START(__kernel_rt_sigreturn_arm)
 	mov r7, #__NR_compat_rt_sigreturn
 	svc #0
 	.fnend
-SYM_FUNC_END(__kernel_rt_sigreturn_arm)
+SYM_CODE_END(__kernel_rt_sigreturn_arm)
 
 	.thumb
 	.fnstart
 	.save {r0-r15}
 	.pad #COMPAT_SIGFRAME_REGS_OFFSET
 	nop
-SYM_FUNC_START(__kernel_sigreturn_thumb)
+SYM_CODE_START(__kernel_sigreturn_thumb)
 	mov r7, #__NR_compat_sigreturn
 	svc #0
 	.fnend
-SYM_FUNC_END(__kernel_sigreturn_thumb)
+SYM_CODE_END(__kernel_sigreturn_thumb)
 
 	.fnstart
 	.save {r0-r15}
 	.pad #COMPAT_RT_SIGFRAME_REGS_OFFSET
 	nop
-SYM_FUNC_START(__kernel_rt_sigreturn_thumb)
+SYM_CODE_START(__kernel_rt_sigreturn_thumb)
 	mov r7, #__NR_compat_rt_sigreturn
 	svc #0
 	.fnend
-SYM_FUNC_END(__kernel_rt_sigreturn_thumb)
+SYM_CODE_END(__kernel_rt_sigreturn_thumb)
diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
index 497f9675071d..3be632177631 100644
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S
@@ -17,10 +17,6 @@
 
 #include "image.h"
 
-/* .exit.text needed in case of alternative patching */
-#define ARM_EXIT_KEEP(x)	x
-#define ARM_EXIT_DISCARD(x)
-
 OUTPUT_ARCH(aarch64)
 ENTRY(_text)
 
@@ -72,8 +68,8 @@ jiffies = jiffies_64;
 
 /*
  * The size of the PE/COFF section that covers the kernel image, which
- * runs from stext to _edata, must be a round multiple of the PE/COFF
- * FileAlignment, which we set to its minimum value of 0x200. 'stext'
+ * runs from _stext to _edata, must be a round multiple of the PE/COFF
+ * FileAlignment, which we set to its minimum value of 0x200. '_stext'
  * itself is 4 KB aligned, so padding out _edata to a 0x200 aligned
  * boundary should be sufficient.
  */
@@ -95,8 +91,6 @@ SECTIONS
 	 * order of matching.
 	 */
 	/DISCARD/ : {
-		ARM_EXIT_DISCARD(EXIT_TEXT)
-		ARM_EXIT_DISCARD(EXIT_DATA)
 		EXIT_CALL
 		*(.discard)
 		*(.discard.*)
@@ -139,6 +133,7 @@ SECTIONS
 
 	idmap_pg_dir = .;
 	. += IDMAP_DIR_SIZE;
+	idmap_pg_end = .;
 
 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0
 	tramp_pg_dir = .;
@@ -161,7 +156,7 @@ SECTIONS
 
 	__exittext_begin = .;
 	.exit.text : {
-		ARM_EXIT_KEEP(EXIT_TEXT)
+		EXIT_TEXT
 	}
 	__exittext_end = .;
 
@@ -175,7 +170,7 @@ SECTIONS
 		*(.altinstr_replacement)
 	}
 
-	. = ALIGN(PAGE_SIZE);
+	. = ALIGN(SEGMENT_ALIGN);
 	__inittext_end = .;
 	__initdata_begin = .;
 
@@ -188,7 +183,7 @@ SECTIONS
 		*(.init.rodata.* .init.bss)	/* from the EFI stub */
 	}
 	.exit.data : {
-		ARM_EXIT_KEEP(EXIT_DATA)
+		EXIT_DATA
 	}
 
 	PERCPU_SECTION(L1_CACHE_BYTES)
@@ -246,6 +241,7 @@ SECTIONS
 	. += INIT_DIR_SIZE;
 	init_pg_end = .;
 
+	. = ALIGN(SEGMENT_ALIGN);
 	__pecoff_data_size = ABSOLUTE(. - __initdata_begin);
 	_end = .;
author	Linus Torvalds <torvalds@linux-foundation.org>	2020-06-01 15:18:27 -0700
committer	Linus Torvalds <torvalds@linux-foundation.org>	2020-06-01 15:18:27 -0700
commit	533b220f7be4e461a5222a223d169b42856741ef (patch)
tree	3684fae5a676b31a4a75e275a0ee5519f0d3c6d9 /arch/arm64/kernel
parent	3ee3723b40d55f473b8c82c60ed0e67f1f9ec6b9 (diff)
parent	082af5ec5080b028f7d0846a6c27cbb87f288205 (diff)
download	lwn-533b220f7be4e461a5222a223d169b42856741ef.tar.gz lwn-533b220f7be4e461a5222a223d169b42856741ef.zip