Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [ 07/44] ARM: 7477/1: vfp: Always save VFP state in vfp_pm_suspend on UP | Date | Mon, 13 Aug 2012 15:02:14 -0700 |
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From: Greg KH <gregkh@linuxfoundation.org>
3.0-stable review patch. If anyone has any objections, please let me know.
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From: Colin Cross <ccross@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 <ido@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 <ccross@android.com> Cc: Barry Song <bs14@csr.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Ido Yariv <ido@wizery.com> Cc: Daniel Drake <dsd@laptop.org> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@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 @@ -412,6 +412,12 @@ 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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