[PATCH] x86: pad assembly functions with INT3

From: Alexey Dobriyan
Date: Mon May 07 2018 - 17:38:04 EST


Use INT3 instead of NOP. All that padding between functions is
an illegal area, no legitimate code should jump into it.

I've checked x86_64 allyesconfig disassembly, all changes looks sane:
INT3 is only used after RET or unconditional JMP.

Signed-off-by: Alexey Dobriyan <adobriyan@xxxxxxxxx>
---

arch/x86/include/asm/linkage.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/include/asm/linkage.h
+++ b/arch/x86/include/asm/linkage.h
@@ -18,7 +18,7 @@
name:

#if defined(CONFIG_X86_64) || defined(CONFIG_X86_ALIGNMENT_16)
-#define __ALIGN .p2align 4, 0x90
+#define __ALIGN .p2align 4, 0xCC
#define __ALIGN_STR __stringify(__ALIGN)
#endif