Date: Sat, 14 May 2011 14:55:15 +0000 (UTC) From: Marcel Moolenaar <marcel@FreeBSD.org> To: cvs-src-old@freebsd.org Subject: cvs commit: src/sys/ia64/ia64 syscall.S Message-ID: <201105141455.p4EEtSAc056376@repoman.freebsd.org>
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marcel 2011-05-14 14:55:15 UTC
FreeBSD src repository
Modified files:
sys/ia64/ia64 syscall.S
Log:
SVN rev 221894 on 2011-05-14 14:55:15Z by marcel
Prefer switching the memory stack from user to kernel *before* switching
the register stack. While the ordering doesn't matter, it creates an
invariant not previously there: the memory stack pointer will always be
larger than the register stack pointer. With this invariant in place,
it's easier to add instrumentation code that detects a stack overflow
because in such a scenario the memory stack pointer and register stack
pointers have crossed each other.
Aside: basic kernel operation needs about half the stack size (~16K)
at most. We have plenty of head room on the kernel stack...
Revision Changes Path
1.17 +4 -3 src/sys/ia64/ia64/syscall.S
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