From cdab6eed39be615703f582831765e14fb0452842 Mon Sep 17 00:00:00 2001 From: Colin Cross Date: Fri, 20 Jul 2012 02:03:42 +0100 Subject: [PATCH] ARM: 7477/1: vfp: Always save VFP state in vfp_pm_suspend on UP 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 , 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. Cc: Barry Song Cc: Catalin Marinas Cc: Ido Yariv Cc: Daniel Drake Cc: Will Deacon Signed-off-by: Colin Cross Signed-off-by: Russell King Signed-off-by: Ben Hutchings --- arch/arm/vfp/vfpmodule.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c index 61e11cea9f75..ad83dadd151d 100644 --- a/arch/arm/vfp/vfpmodule.c +++ b/arch/arm/vfp/vfpmodule.c @@ -453,6 +453,12 @@ 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 */ -- 2.39.5