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| author | Cyril Bur | 2016-09-23 08:18:09 +0200 |
|---|---|---|
| committer | Michael Ellerman | 2016-10-04 07:43:06 +0200 |
| commit | b0f16b46988fde02a1e32078f66a3059d7e53bfc (patch) | |
| tree | c34bb3f61c853e1b91d46f3c003127e695bba4c5 /arch/powerpc/kernel/process.c | |
| parent | powerpc: Always restore FPU/VEC/VSX if hardware transactional memory in use (diff) | |
| download | kernel-qcow2-linux-b0f16b46988fde02a1e32078f66a3059d7e53bfc.tar.gz kernel-qcow2-linux-b0f16b46988fde02a1e32078f66a3059d7e53bfc.tar.xz kernel-qcow2-linux-b0f16b46988fde02a1e32078f66a3059d7e53bfc.zip | |
powerpc: Add check_if_tm_restore_required() to giveup_all()
giveup_all() causes FPU/VMX/VSX facilities to be disabled in a threads
MSR. If the thread performing the giveup was transactional, the kernel
must record which facilities were in use before the giveup as the
thread must have these facilities re-enabled on return to userspace.
>From process.c:
/*
* This is called if we are on the way out to userspace and the
* TIF_RESTORE_TM flag is set. It checks if we need to reload
* FP and/or vector state and does so if necessary.
* If userspace is inside a transaction (whether active or
* suspended) and FP/VMX/VSX instructions have ever been enabled
* inside that transaction, then we have to keep them enabled
* and keep the FP/VMX/VSX state loaded while ever the transaction
* continues. The reason is that if we didn't, and subsequently
* got a FP/VMX/VSX unavailable interrupt inside a transaction,
* we don't know whether it's the same transaction, and thus we
* don't know which of the checkpointed state and the transactional
* state to use.
*/
Calling check_if_tm_restore_required() will set TIF_RESTORE_TM and
save the MSR if needed.
Fixes: c208505 ("powerpc: create giveup_all()")
Signed-off-by: Cyril Bur <cyrilbur@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/kernel/process.c')
| -rw-r--r-- | arch/powerpc/kernel/process.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 3846fab5d1ce..50295670c617 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -446,6 +446,7 @@ void giveup_all(struct task_struct *tsk) return; msr_check_and_set(msr_all_available); + check_if_tm_restore_required(tsk); #ifdef CONFIG_PPC_FPU if (usermsr & MSR_FP) |