From: Greg KH <gre...@linuxfoundation.org>
3.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Colin Cross <ccr...@android.com>
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 <i...@wizery.com>, 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 <ccr...@android.com>
Cc: Barry Song <b...@csr.com>
Cc: Catalin Marinas <catalin.mari...@arm.com>
Cc: Ido Yariv <i...@wizery.com>
Cc: Daniel Drake <d...@laptop.org>
Cc: Will Deacon <will.dea...@arm.com>
Signed-off-by: Russell King <rmk+ker...@arm.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
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 */
--
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