1 files changed, 16 insertions, 0 deletions

diff --git a/arch/x86/include/asm/xsave.h b/arch/x86/include/asm/xsave.h
index 2c4390cae228..06acdbd7570a 100644
--- a/arch/x86/include/asm/xsave.h
+++ b/arch/x86/include/asm/xsave.h
@@ -13,6 +13,12 @@
 
 #define FXSAVE_SIZE     512
 
+#define XSAVE_HDR_SIZE      64
+#define XSAVE_HDR_OFFSET    FXSAVE_SIZE
+
+#define XSAVE_YMM_SIZE      256
+#define XSAVE_YMM_OFFSET    (XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET)
+
 /*
  * These are the features that the OS can handle currently.
  */
@@ -59,6 +65,16 @@ static inline int fpu_xrstor_checking(struct fpu *fpu)
 static inline int xsave_user(struct xsave_struct __user *buf)
 {
         int err;
+
+        /*
+         * Clear the xsave header first, so that reserved fields are
+         * initialized to zero.
+         */
+        err = __clear_user(&buf->xsave_hdr,
+                           sizeof(struct xsave_hdr_struct));
+        if (unlikely(err))
+                return -EFAULT;
+
         __asm__ __volatile__("1: .byte " REX_PREFIX "0x0f,0xae,0x27\n"
                              "2:\n"
                              ".section .fixup,\"ax\"\n"