x86/alternative: Convert ALTERNATIVE_3()

Zap the hack of using an ALTERNATIVE_3() internal label, as suggested by
bgerst:

  https://lore.kernel.org/r/CAMzpN2i4oJ-Dv0qO46Fd-DxNv5z9=x%2BvO%2B8g=47NiiAf8QEJYA@mail.gmail.com

in favor of a label local to this macro only, as it should be done.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240607111701.8366-11-bp@kernel.org

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 007baab32c14018e4ec709c7468f6425b5e3da31..fba12ad237e25d2e118985fc0f05653e8c5f5b76 100644 (file)
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -277,26 +277,10 @@ static inline int alternatives_text_reserved(void *start, void *end)
        N_ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS,      \
                      newinstr_yes, ft_flags)
 
-#define ALTERNATIVE_3(oldinsn, newinsn1, ft_flags1, newinsn2, ft_flags2, \
-                       newinsn3, ft_flags3)                            \
-       OLDINSTR_3(oldinsn, 1, 2, 3)                                    \
-       ".pushsection .altinstructions,\"a\"\n"                         \
-       ALTINSTR_ENTRY(ft_flags1, 1)                                    \
-       ALTINSTR_ENTRY(ft_flags2, 2)                                    \
-       ALTINSTR_ENTRY(ft_flags3, 3)                                    \
-       ".popsection\n"                                                 \
-       ".pushsection .altinstr_replacement, \"ax\"\n"                  \
-       ALTINSTR_REPLACEMENT(newinsn1, 1)                               \
-       ALTINSTR_REPLACEMENT(newinsn2, 2)                               \
-       ALTINSTR_REPLACEMENT(newinsn3, 3)                               \
-       ".popsection\n"
-
-
-#define N_ALTERNATIVE_3(oldinst, newinst1, flag1, newinst2, flag2,     \
-                     newinst3, flag3)                                  \
-       N_ALTERNATIVE(N_ALTERNATIVE_2(oldinst, newinst1, flag1, newinst2, flag2), \
-                     newinst3, flag3)
-
+#define ALTERNATIVE_3(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2, \
+                       newinstr3, ft_flags3)                           \
+       N_ALTERNATIVE(N_ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2), \
+                     newinstr3, ft_flags3)
 /*
  * Alternative instructions for different CPU types or capabilities.
  *

diff --git a/arch/x86/kernel/fpu/xstate.h b/arch/x86/kernel/fpu/xstate.h
index 05df04f3962823c17240deaf31eb7ba9b073d6df..2ee0b9c53dccc42a4eb0ba9774cd2979e06a342b 100644 (file)
--- a/arch/x86/kernel/fpu/xstate.h
+++ b/arch/x86/kernel/fpu/xstate.h
@@ -106,21 +106,17 @@ static inline u64 xfeatures_mask_independent(void)
  * Otherwise, if XSAVEOPT is enabled, XSAVEOPT replaces XSAVE because XSAVEOPT
  * supports modified optimization which is not supported by XSAVE.
  *
- * We use XSAVE as a fallback.
- *
- * The 661 label is defined in the ALTERNATIVE* macros as the address of the
- * original instruction which gets replaced. We need to use it here as the
- * address of the instruction where we might get an exception at.
+ * Use XSAVE as a fallback.
  */
 #define XSTATE_XSAVE(st, lmask, hmask, err)                            \
-       asm volatile(ALTERNATIVE_3(XSAVE,                               \
+       asm volatile("1: " ALTERNATIVE_3(XSAVE,                         \
                                   XSAVEOPT, X86_FEATURE_XSAVEOPT,      \
                                   XSAVEC,   X86_FEATURE_XSAVEC,        \
                                   XSAVES,   X86_FEATURE_XSAVES)        \
                     "\n"                                               \
                     "xor %[err], %[err]\n"                             \
                     "3:\n"                                             \
-                    _ASM_EXTABLE_TYPE_REG(661b, 3b, EX_TYPE_EFAULT_REG, %[err]) \
+                    _ASM_EXTABLE_TYPE_REG(1b, 3b, EX_TYPE_EFAULT_REG, %[err]) \
                     : [err] "=r" (err)                                 \
                     : "D" (st), "m" (*st), "a" (lmask), "d" (hmask)    \
                     : "memory")
@@ -130,11 +126,11 @@ static inline u64 xfeatures_mask_independent(void)
  * XSAVE area format.
  */
 #define XSTATE_XRESTORE(st, lmask, hmask)                              \
-       asm volatile(ALTERNATIVE(XRSTOR,                                \
+       asm volatile("1: " ALTERNATIVE(XRSTOR,                          \
                                 XRSTORS, X86_FEATURE_XSAVES)           \
                     "\n"                                               \
                     "3:\n"                                             \
-                    _ASM_EXTABLE_TYPE(661b, 3b, EX_TYPE_FPU_RESTORE)   \
+                    _ASM_EXTABLE_TYPE(1b, 3b, EX_TYPE_FPU_RESTORE)     \
                     :                                                  \
                     : "D" (st), "m" (*st), "a" (lmask), "d" (hmask)    \
                     : "memory")