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authorPaul Burton <paul.burton@imgtec.com>2016-04-21 12:43:57 +0100
committerSasha Levin <sasha.levin@oracle.com>2016-06-06 19:12:21 -0400
commitdaf7322babd9946b7c2e2eae53d1f68f7665766b (patch)
treed3ec79a948a26a7687697c2606e287e07d84b466
parent49dc90fd14c0ce2ec494d44f1cd6594603d7c4a0 (diff)
MIPS: Disable preemption during prctl(PR_SET_FP_MODE, ...)
[ Upstream commit bd239f1e1429e7781096bf3884bdb1b2b1bb4f28 ] Whilst a PR_SET_FP_MODE prctl is performed there are decisions made based upon whether the task is executing on the current CPU. This may change if we're preempted, so disable preemption to avoid such changes for the lifetime of the mode switch. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Fixes: 9791554b45a2 ("MIPS,prctl: add PR_[GS]ET_FP_MODE prctl options for MIPS") Reviewed-by: Maciej W. Rozycki <macro@imgtec.com> Tested-by: Aurelien Jarno <aurelien@aurel32.net> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: James Hogan <james.hogan@imgtec.com> Cc: stable <stable@vger.kernel.org> # v4.0+ Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/13144/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
-rw-r--r--arch/mips/kernel/process.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index 6b3ae73cda3f..89847bee2b53 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -603,6 +603,9 @@ int mips_set_process_fp_mode(struct task_struct *task, unsigned int value)
if (!(value & PR_FP_MODE_FR) && cpu_has_fpu && cpu_has_mips_r6)
return -EOPNOTSUPP;
+ /* Proceed with the mode switch */
+ preempt_disable();
+
/* Save FP & vector context, then disable FPU & MSA */
if (task->signal == current->signal)
lose_fpu(1);
@@ -661,6 +664,7 @@ int mips_set_process_fp_mode(struct task_struct *task, unsigned int value)
/* Allow threads to use FP again */
atomic_set(&task->mm->context.fp_mode_switching, 0);
+ preempt_enable();
return 0;
}