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authorH. Peter Anvin <hpa@linux.intel.com>2011-08-22 13:27:06 -0700
committerGreg Kroah-Hartman <gregkh@suse.de>2011-08-29 13:29:14 -0700
commit2f431897688c7f81be23ca316a9682c889ac09e0 (patch)
treedfc2859ca1b3980eee4718ea65e178886de96898
parent656e041651bdb780ad525c0983004d01b6f44fd8 (diff)
x86-32, vdso: On system call restart after SYSENTER, use int $0x80
commit 7ca0758cdb7c241cb4e0490a8d95f0eb5b861daf upstream. When we enter a 32-bit system call via SYSENTER or SYSCALL, we shuffle the arguments to match the int $0x80 calling convention. This was probably a design mistake, but it's what it is now. This causes errors if the system call as to be restarted. For SYSENTER, we have to invoke the instruction from the vdso as the return address is hardcoded. Accordingly, we can simply replace the jump in the vdso with an int $0x80 instruction and use the slower entry point for a post-restart. Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Link: http://lkml.kernel.org/r/CA%2B55aFztZ=r5wa0x26KJQxvZOaQq8s2v3u50wCyJcA-Sc4g8gQ@mail.gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--arch/x86/vdso/vdso32/sysenter.S2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/vdso/vdso32/sysenter.S b/arch/x86/vdso/vdso32/sysenter.S
index e2800affa75..e354bceee0e 100644
--- a/arch/x86/vdso/vdso32/sysenter.S
+++ b/arch/x86/vdso/vdso32/sysenter.S
@@ -43,7 +43,7 @@ __kernel_vsyscall:
.space 7,0x90
/* 14: System call restart point is here! (SYSENTER_RETURN-2) */
- jmp .Lenter_kernel
+ int $0x80
/* 16: System call normal return point is here! */
VDSO32_SYSENTER_RETURN: /* Symbol used by sysenter.c via vdso32-syms.h */
pop %ebp