Date: Sun, 3 Oct 2010 13:52:17 +0000 (UTC) From: Konstantin Belousov <kib@FreeBSD.org> To: cvs-src-old@freebsd.org Subject: cvs commit: src/sys/amd64/amd64 machdep.c Message-ID: <201010031352.o93DqYAm051940@repoman.freebsd.org>
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kib 2010-10-03 13:52:17 UTC
FreeBSD src repository
Modified files:
sys/amd64/amd64 machdep.c
Log:
SVN rev 213382 on 2010-10-03 13:52:17Z by kib
The makectx() function, used by kdb_trap() to reconstruct pcb from
trap frame when trap initiated kdb entry, incorrectly calculated the
value of %rsp for trapped thread.
According to Intel(R) 64 and IA-32 Architectures Software Developer's Manual
Volume 3A: System Programming Guide, Part 1, rev. 035, 6.14.2 64-Bit Mode
Stack Frame, "64-bit mode ... pushes SS:RSP unconditionally, rather than
only on a CPL change."
Even assuming the conditional push of the %ss:%rsp, the calculation
was still wrong because sizeof(tf_ss) + sizeof(tf_rsp) == 16 on amd64.
Always use the tf_rsp from trap frame. The change supposedly fixes
stepping when using kgdb backend for kdb.
Submitted by: Zhouyi Zhou <zhouzhouyi gmail com>
PR: amd64/151167
Reviewed by: avg
MFC after: 1 week
Revision Changes Path
1.725 +1 -1 src/sys/amd64/amd64/machdep.c
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