diff options
| author | Ingo Molnar <mingo@elte.hu> | 2004-10-16 19:20:30 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2004-10-16 19:20:30 -0700 |
| commit | c5cada670bf08d89870dd43ea25419f6ffb27c33 (patch) | |
| tree | 18fafc925781ad275ca6b161e4615df2e0b2ff70 /include | |
| parent | 74a82aa978123ad278514ee5553343ff7008b5f7 (diff) | |
[PATCH] tailcall prevention in sys_wait4() and sys_waitid()
A hack to prevent the compiler from generatin tailcalls in these two
functions.
With CONFIG_REGPARM=y, the tailcalled code ends up stomping on the
syscall's argument frame which corrupts userspace's registers.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/asm-i386/linkage.h | 4 | ||||
| -rw-r--r-- | include/linux/linkage.h | 4 |
2 files changed, 8 insertions, 0 deletions
diff --git a/include/asm-i386/linkage.h b/include/asm-i386/linkage.h index e48009fd93c7..af3d8571c5c7 100644 --- a/include/asm-i386/linkage.h +++ b/include/asm-i386/linkage.h @@ -5,6 +5,10 @@ #define FASTCALL(x) x __attribute__((regparm(3))) #define fastcall __attribute__((regparm(3))) +#ifdef CONFIG_REGPARM +# define prevent_tail_call(ret) __asm__ ("" : "=r" (ret) : "0" (ret)) +#endif + #ifdef CONFIG_X86_ALIGNMENT_16 #define __ALIGN .align 16,0x90 #define __ALIGN_STR ".align 16,0x90" diff --git a/include/linux/linkage.h b/include/linux/linkage.h index 09955c0ce848..338f7795d8a0 100644 --- a/include/linux/linkage.h +++ b/include/linux/linkage.h @@ -14,6 +14,10 @@ #define asmlinkage CPP_ASMLINKAGE #endif +#ifndef prevent_tail_call +# define prevent_tail_call(ret) do { } while (0) +#endif + #ifndef __ALIGN #define __ALIGN .align 4,0x90 #define __ALIGN_STR ".align 4,0x90" |