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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2023-06-26 15:14:55 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2023-06-26 15:14:55 -0700 |
| commit | 8c69e7afe9588f9259a6422c6619d7643c76d12c (patch) | |
| tree | 488d55d5b3077bd9d6a25125f371819f5cd946be /arch/x86/lib | |
| parent | aa35a4835e4f4c113c29bc7ea64cfecb951d51b8 (diff) | |
| parent | 2bd4aa9325821551648cf9738d6aa3a49317d7e5 (diff) | |
Merge tag 'x86_alternatives_for_v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 instruction alternatives updates from Borislav Petkov:
- Up until now the Fast Short Rep Mov optimizations implied the
presence of the ERMS CPUID flag. AMD decoupled them with a BIOS
setting so decouple that dependency in the kernel code too
- Teach the alternatives machinery to handle relocations
- Make debug_alternative accept flags in order to see only that set of
patching done one is interested in
- Other fixes, cleanups and optimizations to the patching code
* tag 'x86_alternatives_for_v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/alternative: PAUSE is not a NOP
x86/alternatives: Add cond_resched() to text_poke_bp_batch()
x86/nospec: Shorten RESET_CALL_DEPTH
x86/alternatives: Add longer 64-bit NOPs
x86/alternatives: Fix section mismatch warnings
x86/alternative: Optimize returns patching
x86/alternative: Complicate optimize_nops() some more
x86/alternative: Rewrite optimize_nops() some
x86/lib/memmove: Decouple ERMS from FSRM
x86/alternative: Support relocations in alternatives
x86/alternative: Make debug-alternative selective
Diffstat (limited to 'arch/x86/lib')
| -rw-r--r-- | arch/x86/lib/memmove_64.S | 13 |
1 files changed, 5 insertions, 8 deletions
diff --git a/arch/x86/lib/memmove_64.S b/arch/x86/lib/memmove_64.S index 02661861e5dd..0559b206fb11 100644 --- a/arch/x86/lib/memmove_64.S +++ b/arch/x86/lib/memmove_64.S @@ -38,10 +38,12 @@ SYM_FUNC_START(__memmove) cmp %rdi, %r8 jg 2f - /* FSRM implies ERMS => no length checks, do the copy directly */ +#define CHECK_LEN cmp $0x20, %rdx; jb 1f +#define MEMMOVE_BYTES movq %rdx, %rcx; rep movsb; RET .Lmemmove_begin_forward: - ALTERNATIVE "cmp $0x20, %rdx; jb 1f", "", X86_FEATURE_FSRM - ALTERNATIVE "", "jmp .Lmemmove_erms", X86_FEATURE_ERMS + ALTERNATIVE_2 __stringify(CHECK_LEN), \ + __stringify(CHECK_LEN; MEMMOVE_BYTES), X86_FEATURE_ERMS, \ + __stringify(MEMMOVE_BYTES), X86_FEATURE_FSRM /* * movsq instruction have many startup latency @@ -207,11 +209,6 @@ SYM_FUNC_START(__memmove) movb %r11b, (%rdi) 13: RET - -.Lmemmove_erms: - movq %rdx, %rcx - rep movsb - RET SYM_FUNC_END(__memmove) EXPORT_SYMBOL(__memmove) |