x86, xsave: keep the XSAVE feature mask as an u64

The XSAVE feature mask is a 64-bit number; keep it that way, in order
to avoid the mistake done with rdmsr/wrmsr.  Use the xsetbv() function
provided in the previous patch.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 5 insertions, 7 deletions

diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index e0ed59f5c19f..45723f1fe198 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -552,18 +552,17 @@ static int restore_i387_xsave(void __user *buf)
                 (struct i387_fxsave_struct __user *) &fx_user->_fxsr_env[0];
         struct xsave_hdr_struct *xsave_hdr =
                                 &current->thread.xstate->xsave.xsave_hdr;
-        unsigned int lmask, hmask;
+        u64 mask;
         int err;
 
         if (check_for_xstate(fx, buf, &fx_sw_user))
                 goto fx_only;
 
-        lmask = fx_sw_user.xstate_bv;
-        hmask = fx_sw_user.xstate_bv >> 32;
+        mask = fx_sw_user.xstate_bv;
 
         err = restore_i387_fxsave(buf, fx_sw_user.xstate_size);
 
-        xsave_hdr->xstate_bv &=  (pcntxt_lmask | (((u64) pcntxt_hmask) << 32));
+        xsave_hdr->xstate_bv &= pcntxt_mask;
         /*
          * These bits must be zero.
          */
@@ -573,9 +572,8 @@ static int restore_i387_xsave(void __user *buf)
          * Init the state that is not present in the memory layout
          * and enabled by the OS.
          */
-        lmask = ~(pcntxt_lmask & ~lmask);
-        hmask = ~(pcntxt_hmask & ~hmask);
-        xsave_hdr->xstate_bv &=  (lmask | (((u64) hmask) << 32));
+        mask = ~(pcntxt_mask & ~mask);
+        xsave_hdr->xstate_bv &= mask;
 
         return err;
 fx_only: