05062d96a2
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>
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| .. | ||
| Makefile | ||
| acpi-ext.c | ||
| acpi.c | ||
| asm-offsets.c | ||
| brl_emu.c | ||
| cyclone.c | ||
| domain.c | ||
| efi.c | ||
| efi_stub.S | ||
| entry.S | ||
| entry.h | ||
| fsys.S | ||
| gate-data.S | ||
| gate.S | ||
| gate.lds.S | ||
| head.S | ||
| ia64_ksyms.c | ||
| init_task.c | ||
| iosapic.c | ||
| irq.c | ||
| irq_ia64.c | ||
| irq_lsapic.c | ||
| ivt.S | ||
| machvec.c | ||
| mca.c | ||
| mca_asm.S | ||
| mca_drv.c | ||
| mca_drv.h | ||
| mca_drv_asm.S | ||
| minstate.h | ||
| module.c | ||
| pal.S | ||
| palinfo.c | ||
| patch.c | ||
| perfmon.c | ||
| perfmon_default_smpl.c | ||
| perfmon_generic.h | ||
| perfmon_itanium.h | ||
| perfmon_mckinley.h | ||
| process.c | ||
| ptrace.c | ||
| sal.c | ||
| salinfo.c | ||
| semaphore.c | ||
| setup.c | ||
| sigframe.h | ||
| signal.c | ||
| smp.c | ||
| smpboot.c | ||
| sys_ia64.c | ||
| time.c | ||
| topology.c | ||
| traps.c | ||
| unaligned.c | ||
| unwind.c | ||
| unwind_decoder.c | ||
| unwind_i.h | ||
| vmlinux.lds.S | ||