From: H. Peter Anvin Date: Mon, 22 Aug 2011 20:27:06 +0000 (-0700) Subject: x86-32, vdso: On system call restart after SYSENTER, use int $0x80 X-Git-Tag: v3.1-rc4~52^2 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=7ca0758cdb7c241cb4e0490a8d95f0eb5b861daf;p=profile%2Fcommon%2Fkernel-common.git x86-32, vdso: On system call restart after SYSENTER, use int $0x80 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 Signed-off-by: H. Peter Anvin Link: http://lkml.kernel.org/r/CA%2B55aFztZ=r5wa0x26KJQxvZOaQq8s2v3u50wCyJcA-Sc4g8gQ@mail.gmail.com Cc: --- diff --git a/arch/x86/vdso/vdso32/sysenter.S b/arch/x86/vdso/vdso32/sysenter.S index e2800af..e354bce 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