From: Tom Hughes <tom@compton.nu>
Date: Sun, 16 Dec 2012 09:52:38 +0000 (+0000)
Subject: Make sure the stack pointer is properly aligned when invoking a
X-Git-Tag: svn/VALGRIND_3_9_0~491
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4c791a86cb8a50037b3aca0cd7a251f2bd2bb8b0;p=thirdparty%2Fvalgrind.git

Make sure the stack pointer is properly aligned when invoking a
signal on amd64-linux systems.

The amd64 ABI describes the required alignment on function entry
as follows:

  "In other words, the value (%rsp − 8) is always a multiple
   of 16 when control is transferred to the function entry point.

So we need to 16 byte align and then subtract an extra 8 bytes
to achieve the correct alignment.

Patch from fjgmacc@gmail.com to fix BZ#280114.


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@13182
---

diff --git a/coregrind/m_sigframe/sigframe-amd64-linux.c b/coregrind/m_sigframe/sigframe-amd64-linux.c
index 60f70b36f3..651ea11675 100644
--- a/coregrind/m_sigframe/sigframe-amd64-linux.c
+++ b/coregrind/m_sigframe/sigframe-amd64-linux.c
@@ -452,7 +452,7 @@ static Addr build_rt_sigframe(ThreadState *tst,
    UWord err;
 
    rsp -= sizeof(*frame);
-   rsp = VG_ROUNDDN(rsp, 16);
+   rsp = VG_ROUNDDN(rsp, 16) - 8;
    frame = (struct rt_sigframe *)rsp;
 
    if (!extend(tst, rsp, sizeof(*frame)))