ARM: vfp: Always save VFP state in vfp_pm_suspend

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.

Change-Id: I91f29722d256a3afc1cc04df8b227541434ccffb
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Barry Song <bs14@csr.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Colin Cross <ccross@android.com>

diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c
index 0a96f71f0abd3394d292737e65c832d7c2f1b926..50dbe3545c041836c8eae64053eac4ce7f79dfcb 100644 (file)
--- a/arch/arm/vfp/vfpmodule.c
+++ b/arch/arm/vfp/vfpmodule.c
@@ -451,6 +451,10 @@ static int vfp_pm_suspend(void)
 
                /* disable, just in case */
                fmxr(FPEXC, fmrx(FPEXC) & ~FPEXC_EN);
+       } else if (vfp_current_hw_state[ti->cpu]) {
+               fmxr(FPEXC, fpexc | FPEXC_EN);
+               vfp_save_state(vfp_current_hw_state[ti->cpu], fpexc);
+               fmxr(FPEXC, fpexc);
        }
 
        /* clear any information we had about last context state */