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| author | Uros Bizjak <ubizjak@gmail.com> | 2025-04-18 09:13:51 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2025-04-18 09:33:33 +0200 |
| commit | 42c782fae38f0559e6355707ee0afde9ac16dcc3 (patch) | |
| tree | eabb9d7a83a73b1288cfeb259268f583732f0db3 /arch/x86/power | |
| parent | 4850074ff06fce894a9946c5d3ab8ea13fa33e43 (diff) | |
x86/asm: Remove semicolon from "rep" prefixes
Minimum version of binutils required to compile the kernel is 2.25.
This version correctly handles the "rep" prefixes, so it is possible
to remove the semicolon, which was used to support ancient versions
of GNU as.
Due to the semicolon, the compiler considers "rep; insn" (or its
alternate "rep\n\tinsn" form) as two separate instructions. Removing
the semicolon makes asm length calculations more accurate, consequently
making scheduling and inlining decisions of the compiler more accurate.
Removing the semicolon also enables assembler checks involving "rep"
prefixes. Trying to assemble e.g. "rep addl %eax, %ebx" results in:
Error: invalid instruction `add' after `rep'
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pavel Machek <pavel@kernel.org>
Cc: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20250418071437.4144391-2-ubizjak@gmail.com
Diffstat (limited to 'arch/x86/power')
| -rw-r--r-- | arch/x86/power/hibernate_asm_32.S | 3 | ||||
| -rw-r--r-- | arch/x86/power/hibernate_asm_64.S | 3 |
2 files changed, 2 insertions, 4 deletions
diff --git a/arch/x86/power/hibernate_asm_32.S b/arch/x86/power/hibernate_asm_32.S index 5606a15cf9a1..fb910d9f8471 100644 --- a/arch/x86/power/hibernate_asm_32.S +++ b/arch/x86/power/hibernate_asm_32.S @@ -69,8 +69,7 @@ copy_loop: movl pbe_orig_address(%edx), %edi movl $(PAGE_SIZE >> 2), %ecx - rep - movsl + rep movsl movl pbe_next(%edx), %edx jmp copy_loop diff --git a/arch/x86/power/hibernate_asm_64.S b/arch/x86/power/hibernate_asm_64.S index 8c534c36adfa..f5bda01904c7 100644 --- a/arch/x86/power/hibernate_asm_64.S +++ b/arch/x86/power/hibernate_asm_64.S @@ -138,8 +138,7 @@ SYM_FUNC_START(core_restore_code) movq pbe_address(%rdx), %rsi movq pbe_orig_address(%rdx), %rdi movq $(PAGE_SIZE >> 3), %rcx - rep - movsq + rep movsq /* progress to the next pbe */ movq pbe_next(%rdx), %rdx |