[PATCH] ARM: vfp: Always save VFP state in vfp_pm_suspend

From: Colin Cross
Date: Sun Feb 13 2011 - 18:14:05 EST


vfp_pm_suspend should save the VFP state any time there is
a last_VFP_context. 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 to allow lazy save and restore
Thread 2 initiates suspend
vfp_pm_suspend is called with the VFP disabled, but the
context has not been saved.

Modify vfp_pm_suspend to save the VFP context whenever
last_VFP_context is set.

Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Colin Cross <ccross@xxxxxxxxxxx>
---
arch/arm/vfp/vfpmodule.c | 11 +++++------
1 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c
index 66bf8d1..7aea616 100644
--- a/arch/arm/vfp/vfpmodule.c
+++ b/arch/arm/vfp/vfpmodule.c
@@ -415,13 +415,12 @@ static int vfp_pm_suspend(struct sys_device *dev, pm_message_t state)
struct thread_info *ti = current_thread_info();
u32 fpexc = fmrx(FPEXC);

- /* if vfp is on, then save state for resumption */
- if (fpexc & FPEXC_EN) {
+ /* save state for resume */
+ if (last_VFP_context[ti->cpu]) {
printk(KERN_DEBUG "%s: saving vfp state\n", __func__);
- vfp_save_state(&ti->vfpstate, fpexc);
-
- /* disable, just in case */
- fmxr(FPEXC, fmrx(FPEXC) & ~FPEXC_EN);
+ fmxr(FPEXC, fpexc | FPEXC_EN);
+ vfp_save_state(last_VFP_context[ti->cpu], fpexc);
+ fmxr(FPEXC, fpexc & ~FPEXC_EN);
}

/* clear any information we had about last context state */
--
1.7.3.1

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