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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>
This commit is contained in:
Eric Biggers 2017-09-24 12:59:08 +02:00 committed by Ingo Molnar
parent 80d8ae86b3
commit b89eda482d
1 changed files with 4 additions and 6 deletions
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10
arch/x86/kernel/fpu/xstate.c
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@ -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;
}