x86/fpu: Eliminate the 'xfeatures' local variable in copy_kernel_to_xstate()

We have this information in the xstate_header.

Signed-off-by: Eric Biggers <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Eric Biggers <[email protected]>
Cc: Fenghua Yu <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Kevin Hao <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Michael Halcrow <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Wanpeng Li <[email protected]>
Cc: Yu-cheng Yu <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 02591b96bb25405745047ff44ab7e84e6cd0a65a..c97c4a9db52a80f617c85eafb864b83652baecc6 100644 (file)
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -1146,7 +1146,6 @@ int copy_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf)
 {
        unsigned int offset, size;
        int i;
-       u64 xfeatures;
        u64 allowed_features;
        struct xstate_header hdr;
 
@@ -1154,20 +1153,19 @@ int copy_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf)
        size = sizeof(hdr);
 
        memcpy(&hdr, kbuf + offset, size);
-       xfeatures = hdr.xfeatures;
 
        /*
         * Reject if the user sets any disabled or supervisor features:
         */
        allowed_features = xfeatures_mask & ~XFEATURE_MASK_SUPERVISOR;
 
-       if (xfeatures & ~allowed_features)
+       if (hdr.xfeatures & ~allowed_features)
                return -EINVAL;
 
        for (i = 0; i < XFEATURE_MAX; i++) {
                u64 mask = ((u64)1 << i);
 
-               if (xfeatures & mask) {
+               if (hdr.xfeatures & mask) {
                        void *dst = __raw_xsave_addr(xsave, 1 << i);
 
                        offset = xstate_offsets[i];
@@ -1177,7 +1175,7 @@ int copy_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf)
                }
        }
 
-       if (xfeatures_mxcsr_quirk(xfeatures)) {
+       if (xfeatures_mxcsr_quirk(hdr.xfeatures)) {
                offset = offsetof(struct fxregs_state, mxcsr);
                size = MXCSR_AND_FLAGS_SIZE;
                memcpy(&xsave->i387.mxcsr, kbuf + offset, size);
@@ -1192,7 +1190,7 @@ int copy_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf)
        /*
         * Add back in the features that came in from userspace:
         */
-       xsave->header.xfeatures |= xfeatures;
+       xsave->header.xfeatures |= hdr.xfeatures;
 
        return 0;
 }