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authorPaul Burton <paul.burton@imgtec.com>2016-04-21 12:43:57 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-06-07 18:14:31 -0700
commit57a94749251c3a5ce07b237a16723be8ea01b1ac (patch)
tree03b82e04712840cbe0b0a864be826a895ca81f30 /arch/mips
parent6dc9f27c09cf380f70505c08bcd805e4495ab4f8 (diff)
MIPS: Disable preemption during prctl(PR_SET_FP_MODE, ...)
commit bd239f1e1429e7781096bf3884bdb1b2b1bb4f28 upstream. 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: 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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/mips')
-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;
}