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-rw-r--r--arch/arm/vfp/vfpmodule.c22
1 files changed, 21 insertions, 1 deletions
diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c
index 05872d92fca2..bc683b8219b5 100644
--- a/arch/arm/vfp/vfpmodule.c
+++ b/arch/arm/vfp/vfpmodule.c
@@ -564,6 +564,21 @@ int vfp_preserve_user_clear_hwstate(struct user_vfp __user *ufp,
if (err)
return -EFAULT;
+
+ /* Ensure that VFP is disabled. */
+ vfp_flush_hwstate(thread);
+
+ /*
+ * As per the PCS, clear the length and stride bits for function
+ * entry.
+ */
+ hwstate->fpscr &= ~(FPSCR_LENGTH_MASK | FPSCR_STRIDE_MASK);
+
+ /*
+ * Disable VFP in the hwstate so that we can detect if it gets
+ * used.
+ */
+ hwstate->fpexc &= ~FPEXC_EN;
return 0;
}
@@ -576,7 +591,12 @@ int vfp_restore_user_hwstate(struct user_vfp __user *ufp,
unsigned long fpexc;
int err = 0;
- vfp_flush_hwstate(thread);
+ /*
+ * If VFP has been used, then disable it to avoid corrupting
+ * the new thread state.
+ */
+ if (hwstate->fpexc & FPEXC_EN)
+ vfp_flush_hwstate(thread);
/*
* Copy the floating point registers. There can be unused