Commit 57a94749 authored by Paul Burton's avatar Paul Burton Committed by Greg Kroah-Hartman

MIPS: Disable preemption during prctl(PR_SET_FP_MODE, ...)

commit bd239f1e 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: default avatarPaul Burton <paul.burton@imgtec.com>
Fixes: 9791554b ("MIPS,prctl: add PR_[GS]ET_FP_MODE prctl options for MIPS")
Reviewed-by: default avatarMaciej W. Rozycki <macro@imgtec.com>
Tested-by: default avatarAurelien 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: default avatarRalf Baechle <ralf@linux-mips.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 6dc9f27c
......@@ -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;
}
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