Commit-ID:  3d703477bcfe8bb57079d97198cf1e342fe1fef9
Gitweb:     http://git.kernel.org/tip/3d703477bcfe8bb57079d97198cf1e342fe1fef9
Author:     Eric Biggers <[email protected]>
AuthorDate: Sun, 24 Sep 2017 12:59:11 +0200
Committer:  Ingo Molnar <[email protected]>
CommitDate: Tue, 26 Sep 2017 09:43:48 +0200

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

We now have this field in hdr.xfeatures.

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]>
---
 arch/x86/kernel/fpu/xstate.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 0cd7b73..b6d78b7 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -1197,7 +1197,6 @@ int copy_user_to_xstate(struct xregs_state *xsave, const 
void __user *ubuf)
 {
        unsigned int offset, size;
        int i;
-       u64 xfeatures;
        u64 allowed_features;
        struct xstate_header hdr;
 
@@ -1207,20 +1206,18 @@ int copy_user_to_xstate(struct xregs_state *xsave, 
const void __user *ubuf)
        if (__copy_from_user(&hdr, ubuf + offset, size))
                return -EFAULT;
 
-       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];
@@ -1231,7 +1228,7 @@ int copy_user_to_xstate(struct xregs_state *xsave, const 
void __user *ubuf)
                }
        }
 
-       if (xfeatures_mxcsr_quirk(xfeatures)) {
+       if (xfeatures_mxcsr_quirk(hdr.xfeatures)) {
                offset = offsetof(struct fxregs_state, mxcsr);
                size = MXCSR_AND_FLAGS_SIZE;
                if (__copy_from_user(&xsave->i387.mxcsr, ubuf + offset, size))
@@ -1247,7 +1244,7 @@ int copy_user_to_xstate(struct xregs_state *xsave, const 
void __user *ubuf)
        /*
         * Add back in the features that came in from userspace:
         */
-       xsave->header.xfeatures |= xfeatures;
+       xsave->header.xfeatures |= hdr.xfeatures;
 
        return 0;
 }

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