Patch "MIPS: Avoid a BUG warning during prctl(PR_SET_FP_MODE, ...)" has been added to the 4.7-stable tree

Patch "MIPS: Avoid a BUG warning during prctl(PR_SET_FP_MODE, ...)" has been added to the 4.7-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    MIPS: Avoid a BUG warning during prctl(PR_SET_FP_MODE, ...)

to the 4.7-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     mips-avoid-a-bug-warning-during-prctl-pr_set_fp_mode.patch
and it can be found in the queue-4.7 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From b244614a60ab7ce54c12a9cbe15cfbf8d79d0967 Mon Sep 17 00:00:00 2001
From: Marcin Nowakowski <marcin.nowakowski@imgtec.com>
Date: Wed, 31 Aug 2016 12:33:23 +0200
Subject: MIPS: Avoid a BUG warning during prctl(PR_SET_FP_MODE, ...)

From: Marcin Nowakowski <marcin.nowakowski@imgtec.com>

commit b244614a60ab7ce54c12a9cbe15cfbf8d79d0967 upstream.

cpu_has_fpu macro uses smp_processor_id() and is currently executed
with preemption enabled, that triggers the warning at runtime.

It is assumed throughout the kernel that if any CPU has an FPU, then all
CPUs would have an FPU as well, so it is safe to perform the check with
preemption enabled - change the code to use raw_ variant of the check to
avoid the warning.

Signed-off-by: Marcin Nowakowski <marcin.nowakowski@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14125/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/mips/kernel/process.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -591,14 +591,14 @@ int mips_set_process_fp_mode(struct task
 		return -EOPNOTSUPP;
 
 	/* Avoid inadvertently triggering emulation */
-	if ((value & PR_FP_MODE_FR) && cpu_has_fpu &&
-	    !(current_cpu_data.fpu_id & MIPS_FPIR_F64))
+	if ((value & PR_FP_MODE_FR) && raw_cpu_has_fpu &&
+	    !(raw_current_cpu_data.fpu_id & MIPS_FPIR_F64))
 		return -EOPNOTSUPP;
-	if ((value & PR_FP_MODE_FRE) && cpu_has_fpu && !cpu_has_fre)
+	if ((value & PR_FP_MODE_FRE) && raw_cpu_has_fpu && !cpu_has_fre)
 		return -EOPNOTSUPP;
 
 	/* FR = 0 not supported in MIPS R6 */
-	if (!(value & PR_FP_MODE_FR) && cpu_has_fpu && cpu_has_mips_r6)
+	if (!(value & PR_FP_MODE_FR) && raw_cpu_has_fpu && cpu_has_mips_r6)
 		return -EOPNOTSUPP;
 
 	/* Proceed with the mode switch */


Patches currently in stable-queue which might be from marcin.nowakowski@imgtec.com are

queue-4.7/mips-avoid-a-bug-warning-during-prctl-pr_set_fp_mode.patch