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authorPeter Chubb <peterc@gelato.unsw.edu.au>2005-06-08 15:50:20 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-06-08 16:21:14 -0700
commit05062d96a23ec0959ee5ea969f40813170c73c0e (patch)
tree9aa09b58ff455cc43b81cae10d3c4dac9fe9f462 /arch/ia64/kernel/perfmon.c
parentf829fd23c87918374bac0d90404fe12f0e788d52 (diff)
[PATCH] ia64: fix floating-point preemption problem
There've been reports of problems with CONFIG_PREEMPT=y and the high floating point partition. This is caused by the possibility of preemption and rescheduling on a different processor while saving or restioirng the high partition. The only places where the FPU state is touched are in ptrace, in switch_to(), and where handling a floating-point exception. In switch_to() preemption is off. So it's only in trap.c and ptrace.c that we need to prevent preemption. Here is a patch that adds commentary to make the conditions clear, and adds appropriate preempt_{en,dis}able() calls to make it so. In trap.c I use preempt_enable_no_resched(), as we're about to return to user space where the preemption flag will be checked anyway. Signed-off-by: Peter Chubb <peterc@gelato.unsw.edu.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/ia64/kernel/perfmon.c')
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