Merge branch into tip/master: 'x86/boot'

 # New commits in x86/boot:
    dc2a1671d983 ("x86/boot: Drop unused implementation of panic()")
    a9bc562daaf2 ("x86/boot: Move unaccepted memory handling out of the decompressor")
    0ffdb6c1ea44 ("x86/tdx: Share tdx_panic() with the EFI stub")
    b24bc9dec9c8 ("x86/pvh: Really inline memcmp() and memset() to fix unbootable VMs")
    85f11c17b261 ("x86/asm: Group inline string functions")
    5b6fe00406ce ("x86/asm, x86/boot: Carve out inline memcmp() into a separate header")
    94509668fccf ("x86/boot: Remove redundant "cc" clobber in memcmp() and document it")
    6744e454d877 ("x86/boot: Use BASE_BAUD and DEFAULT_SERIAL_PORT")

Signed-off-by: Ingo Molnar <mingo@kernel.org>

5 files changed, 57 insertions, 21 deletions

diff --git a/arch/x86/include/asm/cpuid/api.h b/arch/x86/include/asm/cpuid/api.h
index 82eddfa2347b..2d9f3d4d63de 100644
--- a/arch/x86/include/asm/cpuid/api.h
+++ b/arch/x86/include/asm/cpuid/api.h
@@ -204,7 +204,7 @@ static inline u32 cpuid_base_hypervisor(const char *sig, u32 leaves)
 		 * from PVH early boot code before instrumentation is set up
 		 * and memcmp() itself may be instrumented.
 		 */
-		if (!__builtin_memcmp(sig, signature, 12) &&
+		if (!__inline_memcmp(sig, signature, 12) &&
 		    (leaves == 0 || ((eax - base) >= leaves)))
 			return base;
 	}
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index 9e7a077c445d..4b5db43cc0b1 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -517,6 +517,7 @@ void snp_accept_memory(phys_addr_t start, phys_addr_t end);
 u64 snp_get_unsupported_features(u64 status);
 u64 sev_get_status(void);
 void sev_show_status(void);
+bool early_is_sevsnp_guest(void);
 int prepare_pte_enc(struct pte_enc_desc *d);
 void set_pte_enc_mask(pte_t *kpte, unsigned long pfn, pgprot_t new_prot);
 void snp_kexec_finish(void);
@@ -626,6 +627,7 @@ static inline void snp_accept_memory(phys_addr_t start, phys_addr_t end) { }
 static inline u64 snp_get_unsupported_features(u64 status) { return 0; }
 static inline u64 sev_get_status(void) { return 0; }
 static inline void sev_show_status(void) { }
+static inline bool early_is_sevsnp_guest(void) { return false; }
 static inline int prepare_pte_enc(struct pte_enc_desc *d) { return 0; }
 static inline void set_pte_enc_mask(pte_t *kpte, unsigned long pfn, pgprot_t new_prot) { }
 static inline void snp_kexec_finish(void) { }
diff --git a/arch/x86/include/asm/shared/string.h b/arch/x86/include/asm/shared/string.h
new file mode 100644
index 000000000000..6bef90d62a21
--- /dev/null
+++ b/arch/x86/include/asm/shared/string.h
@@ -0,0 +1,52 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_SHARED_STRING_H
+#define _ASM_X86_SHARED_STRING_H
+
+static __always_inline void *__inline_memcpy(void *to, const void *from, size_t len)
+{
+	void *ret = to;
+
+	asm volatile("rep movsb"
+		     : "+D" (to), "+S" (from), "+c" (len)
+		     : : "memory");
+	return ret;
+}
+
+static __always_inline void *__inline_memset(void *s, int v, size_t n)
+{
+	void *ret = s;
+
+	asm volatile("rep stosb"
+		     : "+D" (s), "+c" (n)
+		     : "a" ((uint8_t)v)
+		     : "memory");
+	return ret;
+}
+
+/*
+ * Returns:	0 (equal)
+ * 		1 (not equal)
+ *
+ * In contrast, the regular memcmp() follows glibc return value semantics.
+ */
+static __always_inline int __inline_memcmp(const void *s1, const void *s2, size_t len)
+{
+	bool diff;
+
+	/*
+	 * Make sure ZF is properly set in the len==0 case because in it,
+	 * RCX==0 and the REPE; CMPSB won't get executed.
+	 *
+	 * The "cc" clobber has no meaning anymore, just source compatibility.
+	 * On x86 the flag status bits are automatically added to the clobber
+	 * set when there are no =@ccXY constraints. Keep it as documentation.
+	 */
+	asm volatile("test %3, %3\n\t"
+		     "repe cmpsb"
+		     : "=@ccnz" (diff), "+D" (s1), "+S" (s2), "+c" (len)
+		     : : /* "cc", */ "memory");
+
+	return diff;
+}
+
+#endif /* _ASM_X86_SHARED_STRING_H */
diff --git a/arch/x86/include/asm/shared/tdx.h b/arch/x86/include/asm/shared/tdx.h
index f20e91d7ac35..e5785258e547 100644
--- a/arch/x86/include/asm/shared/tdx.h
+++ b/arch/x86/include/asm/shared/tdx.h
@@ -171,6 +171,7 @@ static inline u64 _tdx_hypercall(u64 fn, u64 r12, u64 r13, u64 r14, u64 r15)
 	return __tdx_hypercall(&args);
 }
 
+void __noreturn tdx_panic(const char *msg);
 
 /* Called from __tdx_hypercall() for unrecoverable failure */
 void __noreturn __tdx_hypercall_failed(void);
diff --git a/arch/x86/include/asm/string.h b/arch/x86/include/asm/string.h
index 9cb5aae7fba9..dbf59f0d4cca 100644
--- a/arch/x86/include/asm/string.h
+++ b/arch/x86/include/asm/string.h
@@ -8,25 +8,6 @@
 # include <asm/string_64.h>
 #endif
 
-static __always_inline void *__inline_memcpy(void *to, const void *from, size_t len)
-{
-	void *ret = to;
-
-	asm volatile("rep movsb"
-		     : "+D" (to), "+S" (from), "+c" (len)
-		     : : "memory");
-	return ret;
-}
-
-static __always_inline void *__inline_memset(void *s, int v, size_t n)
-{
-	void *ret = s;
-
-	asm volatile("rep stosb"
-		     : "+D" (s), "+c" (n)
-		     : "a" ((uint8_t)v)
-		     : "memory");
-	return ret;
-}
+#include <asm/shared/string.h>
 
 #endif /* _ASM_X86_STRING_H */