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x86/asm: Differentiate between code and function alignment

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Create SYM_F_ALIGN to differentiate alignment requirements between
SYM_CODE and SYM_FUNC.

This distinction is useful later when adding padding in front of
functions; IOW this allows following the compiler's
patchable-function-entry option.

[peterz: Changelog]

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220915111143.824822743@infradead.org
This commit is contained in:
Thomas Gleixner 2022-09-15 13:10:48 +02:00 committed by Peter Zijlstra
parent d49a062621
commit 8eb5d34e77
1 changed files with 9 additions and 5 deletions
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14
arch/x86/include/asm/linkage.h
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@ -12,11 +12,15 @@
#define asmlinkage CPP_ASMLINKAGE __attribute__((regparm(0)))
#endif /* CONFIG_X86_32 */
#ifdef __ASSEMBLY__
#define __ALIGN .balign CONFIG_FUNCTION_ALIGNMENT, 0x90;
#define __ALIGN_STR __stringify(__ALIGN)
#define ASM_FUNC_ALIGN __ALIGN_STR
#define __FUNC_ALIGN __ALIGN
#define SYM_F_ALIGN __FUNC_ALIGN
#ifdef __ASSEMBLY__
#if defined(CONFIG_RETHUNK) && !defined(__DISABLE_EXPORTS) && !defined(BUILD_VDSO)
#define RET jmp __x86_return_thunk
#else /* CONFIG_RETPOLINE */
@ -55,7 +59,7 @@
/* SYM_FUNC_START -- use for global functions */
#define SYM_FUNC_START(name) \
SYM_START(name, SYM_L_GLOBAL, SYM_A_ALIGN) \
SYM_START(name, SYM_L_GLOBAL, SYM_F_ALIGN) \
ENDBR
/* SYM_FUNC_START_NOALIGN -- use for global functions, w/o alignment */
@ -65,7 +69,7 @@
/* SYM_FUNC_START_LOCAL -- use for local functions */
#define SYM_FUNC_START_LOCAL(name) \
SYM_START(name, SYM_L_LOCAL, SYM_A_ALIGN) \
SYM_START(name, SYM_L_LOCAL, SYM_F_ALIGN) \
ENDBR
/* SYM_FUNC_START_LOCAL_NOALIGN -- use for local functions, w/o alignment */
@ -75,7 +79,7 @@
/* SYM_FUNC_START_WEAK -- use for weak functions */
#define SYM_FUNC_START_WEAK(name) \
SYM_START(name, SYM_L_WEAK, SYM_A_ALIGN) \
SYM_START(name, SYM_L_WEAK, SYM_F_ALIGN) \
ENDBR
/* SYM_FUNC_START_WEAK_NOALIGN -- use for weak functions, w/o alignment */