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
  ...

9 files changed, 4 insertions, 26 deletions

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 462e5c78d9d8..6e23037f3b51 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -92,6 +92,7 @@ config X86
 	select ARCH_USE_BUILTIN_BSWAP
 	select ARCH_USE_QUEUED_RWLOCKS
 	select ARCH_USE_QUEUED_SPINLOCKS
+	select ARCH_USE_SYM_ANNOTATIONS
 	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
 	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
 	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index 2e74690b028a..f909d3ce36e6 100644
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -99,15 +99,6 @@ config DEBUG_WX
 
 	  If in doubt, say "Y".
 
-config DOUBLEFAULT
-	default y
-	bool "Enable doublefault exception handler" if EXPERT && X86_32
-	---help---
-	  This option allows trapping of rare doublefault exceptions that
-	  would otherwise cause a system to silently reboot. Disabling this
-	  option saves about 4k and might cause you much additional grey
-	  hair.
-
 config DEBUG_TLBFLUSH
 	bool "Set upper limit of TLB entries to flush one-by-one"
 	depends on DEBUG_KERNEL
diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index 7e7ffb7a5147..ac232f456396 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -1536,7 +1536,6 @@ SYM_CODE_START(debug)
 	jmp	common_exception
 SYM_CODE_END(debug)
 
-#ifdef CONFIG_DOUBLEFAULT
 SYM_CODE_START(double_fault)
 1:
 	/*
@@ -1576,7 +1575,6 @@ SYM_CODE_START(double_fault)
 	hlt
 	jmp 1b
 SYM_CODE_END(double_fault)
-#endif
 
 /*
  * NMI is doubly nasty.  It can happen on the first instruction of
diff --git a/arch/x86/include/asm/doublefault.h b/arch/x86/include/asm/doublefault.h
index af9a14ac8962..54a6e4a2e132 100644
--- a/arch/x86/include/asm/doublefault.h
+++ b/arch/x86/include/asm/doublefault.h
@@ -2,7 +2,7 @@
 #ifndef _ASM_X86_DOUBLEFAULT_H
 #define _ASM_X86_DOUBLEFAULT_H
 
-#if defined(CONFIG_X86_32) && defined(CONFIG_DOUBLEFAULT)
+#ifdef CONFIG_X86_32
 extern void doublefault_init_cpu_tss(void);
 #else
 static inline void doublefault_init_cpu_tss(void)
diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h
index 6f6c417e1e46..2ae904bf25e4 100644
--- a/arch/x86/include/asm/traps.h
+++ b/arch/x86/include/asm/traps.h
@@ -69,9 +69,7 @@ dotraplinkage void do_overflow(struct pt_regs *regs, long error_code);
 dotraplinkage void do_bounds(struct pt_regs *regs, long error_code);
 dotraplinkage void do_invalid_op(struct pt_regs *regs, long error_code);
 dotraplinkage void do_device_not_available(struct pt_regs *regs, long error_code);
-#if defined(CONFIG_X86_64) || defined(CONFIG_DOUBLEFAULT)
 dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code, unsigned long cr2);
-#endif
 dotraplinkage void do_coprocessor_segment_overrun(struct pt_regs *regs, long error_code);
 dotraplinkage void do_invalid_TSS(struct pt_regs *regs, long error_code);
 dotraplinkage void do_segment_not_present(struct pt_regs *regs, long error_code);
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index ba89cabe5fcf..2a7c3afa62e2 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -102,9 +102,7 @@ obj-$(CONFIG_KEXEC_FILE)	+= kexec-bzimage64.o
 obj-$(CONFIG_CRASH_DUMP)	+= crash_dump_$(BITS).o
 obj-y				+= kprobes/
 obj-$(CONFIG_MODULES)		+= module.o
-ifeq ($(CONFIG_X86_32),y)
-obj-$(CONFIG_DOUBLEFAULT)	+= doublefault_32.o
-endif
+obj-$(CONFIG_X86_32)		+= doublefault_32.o
 obj-$(CONFIG_KGDB)		+= kgdb.o
 obj-$(CONFIG_VM86)		+= vm86_32.o
 obj-$(CONFIG_EARLY_PRINTK)	+= early_printk.o
diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c
index 8e3a8fedfa4d..722fd712e1cf 100644
--- a/arch/x86/kernel/dumpstack_32.c
+++ b/arch/x86/kernel/dumpstack_32.c
@@ -87,7 +87,6 @@ static bool in_softirq_stack(unsigned long *stack, struct stack_info *info)
 
 static bool in_doublefault_stack(unsigned long *stack, struct stack_info *info)
 {
-#ifdef CONFIG_DOUBLEFAULT
 	struct cpu_entry_area *cea = get_cpu_entry_area(raw_smp_processor_id());
 	struct doublefault_stack *ss = &cea->doublefault_stack;
 
@@ -103,9 +102,6 @@ static bool in_doublefault_stack(unsigned long *stack, struct stack_info *info)
 	info->next_sp	= (unsigned long *)this_cpu_read(cpu_tss_rw.x86_tss.sp);
 
 	return true;
-#else
-	return false;
-#endif
 }
 
 
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index f7cfb9d0ad02..428186d9de46 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -256,7 +256,6 @@ __visible void __noreturn handle_stack_overflow(const char *message,
 }
 #endif
 
-#if defined(CONFIG_X86_64) || defined(CONFIG_DOUBLEFAULT)
 /*
  * Runs on an IST stack for x86_64 and on a special task stack for x86_32.
  *
@@ -380,7 +379,6 @@ dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code, unsign
 	die("double fault", regs, error_code);
 	panic("Machine halted.");
 }
-#endif
 
 dotraplinkage void do_bounds(struct pt_regs *regs, long error_code)
 {
diff --git a/arch/x86/mm/cpu_entry_area.c b/arch/x86/mm/cpu_entry_area.c
index 56f9189bbadb..5199d8a1daf1 100644
--- a/arch/x86/mm/cpu_entry_area.c
+++ b/arch/x86/mm/cpu_entry_area.c
@@ -17,7 +17,7 @@ static DEFINE_PER_CPU_PAGE_ALIGNED(struct exception_stacks, exception_stacks);
 DEFINE_PER_CPU(struct cea_exception_stacks*, cea_exception_stacks);
 #endif
 
-#if defined(CONFIG_X86_32) && defined(CONFIG_DOUBLEFAULT)
+#ifdef CONFIG_X86_32
 DECLARE_PER_CPU_PAGE_ALIGNED(struct doublefault_stack, doublefault_stack);
 #endif
 
@@ -114,12 +114,10 @@ static void __init percpu_setup_exception_stacks(unsigned int cpu)
 #else
 static inline void percpu_setup_exception_stacks(unsigned int cpu)
 {
-#ifdef CONFIG_DOUBLEFAULT
 	struct cpu_entry_area *cea = get_cpu_entry_area(cpu);
 
 	cea_map_percpu_pages(&cea->doublefault_stack,
 			     &per_cpu(doublefault_stack, cpu), 1, PAGE_KERNEL);
-#endif
 }
 #endif