This is a note to let you know that I've just added the patch titled
ARM: 7477/1: vfp: Always save VFP state in vfp_pm_suspend on UP
to the 3.5-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:
arm-7477-1-vfp-always-save-vfp-state-in-vfp_pm_suspend-on-up.patch
and it can be found in the queue-3.5 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 24b35521b8ddf088531258f06f681bb7b227bf47 Mon Sep 17 00:00:00 2001
From: Colin Cross <[email protected]>
Date: Fri, 20 Jul 2012 02:03:42 +0100
Subject: ARM: 7477/1: vfp: Always save VFP state in vfp_pm_suspend on UP
From: Colin Cross <[email protected]>
commit 24b35521b8ddf088531258f06f681bb7b227bf47 upstream.
vfp_pm_suspend should save the VFP state in suspend after
any lazy context switch. If it only saves when the VFP is enabled,
the state can get lost when, on a UP system:
Thread 1 uses the VFP
Context switch occurs to thread 2, VFP is disabled but the
VFP context is not saved
Thread 2 initiates suspend
vfp_pm_suspend is called with the VFP disabled, and the unsaved
VFP context of Thread 1 in the registers
Modify vfp_pm_suspend to save the VFP context whenever
vfp_current_hw_state is not NULL.
Includes a fix from Ido Yariv <[email protected]>, who pointed out that on
SMP systems, the state pointer can be pointing to a freed task struct if
a task exited on another cpu, fixed by using #ifndef CONFIG_SMP in the
new if clause.
Signed-off-by: Colin Cross <[email protected]>
Cc: Barry Song <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Ido Yariv <[email protected]>
Cc: Daniel Drake <[email protected]>
Cc: Will Deacon <[email protected]>
Signed-off-by: Russell King <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/arm/vfp/vfpmodule.c | 6 ++++++
1 file changed, 6 insertions(+)
--- a/arch/arm/vfp/vfpmodule.c
+++ b/arch/arm/vfp/vfpmodule.c
@@ -457,6 +457,12 @@ static int vfp_pm_suspend(void)
/* disable, just in case */
fmxr(FPEXC, fmrx(FPEXC) & ~FPEXC_EN);
+ } else if (vfp_current_hw_state[ti->cpu]) {
+#ifndef CONFIG_SMP
+ fmxr(FPEXC, fpexc | FPEXC_EN);
+ vfp_save_state(vfp_current_hw_state[ti->cpu], fpexc);
+ fmxr(FPEXC, fpexc);
+#endif
}
/* clear any information we had about last context state */
Patches currently in stable-queue which might be from [email protected] are
queue-3.5/arm-7476-1-vfp-only-clear-vfp-state-for-current-cpu-in-vfp_pm_suspend.patch
queue-3.5/arm-7477-1-vfp-always-save-vfp-state-in-vfp_pm_suspend-on-up.patch
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