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Re: panic! panic! panic! sigh.. panic!
On Mon, Sep 22, 2008 at 09:46:07PM +0200, Vincent wrote:
> Greg Troxel a ?crit :
> > The kernel doesn't save any of these registers on entry into the kernel
> > (via an interrupt or system call) and doesn't restore them on exit. It
> > also doesn't save and restore them on internal scheduling. If you
> > compile the kernel with MMX or SSE<n> enabled the kernel will sooner
> > or later globber some state and you get a panic.
> Since eons I've had "-msse2 -mfpmath=sse -march=pentium4" in my
> /etc/mk.conf, resulting in my i386 kernel being built with those
> options. I've never seen a crash likely caused by these superfluous
> flags. I'm dubious if, anyhow, SIMD integer operations could be of a
> significant help in kernel operations.
Beware, the compile might decide to use the sse (ie fp) registers
for operations that don't involve fp.
David Laight: david%l8s.co.uk@localhost
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