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authorEric Biggers <ebiggers@google.com>2017-09-24 12:59:08 +0200
committerIngo Molnar <mingo@kernel.org>2017-09-26 09:43:46 +0200
commitb89eda482d7849a1c146b6d0a42f4e76369bb08e (patch)
treeb38e82377700e300c0408cacfa210c6389b0586d
parent80d8ae86b36791a545ca28ddc95133ea59bba6e0 (diff)
downloadlinux-b89eda482d7849a1c146b6d0a42f4e76369bb08e.tar.bz2
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 <ebiggers@google.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Eric Biggers <ebiggers3@gmail.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Kees Cook <keescook@chromium.org> Cc: Kevin Hao <haokexin@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michael Halcrow <mhalcrow@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Wanpeng Li <wanpeng.li@hotmail.com> Cc: Yu-cheng Yu <yu-cheng.yu@intel.com> Cc: kernel-hardening@lists.openwall.com Link: http://lkml.kernel.org/r/20170924105913.9157-6-mingo@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r--arch/x86/kernel/fpu/xstate.c10
1 files changed, 4 insertions, 6 deletions
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 02591b96bb25..c97c4a9db52a 100644
--- 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;
}