[tip:,x86/core] x86/asm: Differentiate between code and function alignment
Commit Message
The following commit has been merged into the x86/core branch of tip:
Commit-ID: 8eb5d34e77c63fde8af21c691bcf6e3cd87f7829
Gitweb: https://git.kernel.org/tip/8eb5d34e77c63fde8af21c691bcf6e3cd87f7829
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Thu, 15 Sep 2022 13:10:48 +02:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Mon, 17 Oct 2022 16:40:58 +02:00
x86/asm: Differentiate between code and function alignment
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
---
arch/x86/include/asm/linkage.h | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
@@ -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 */