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authorIngo Molnar <mingo@kernel.org>2017-09-23 15:59:54 +0300
committerIngo Molnar <mingo@kernel.org>2017-09-24 14:04:32 +0300
commit79fecc2b7506f29fb91becc65e8788e5ae7eba9f (patch)
tree5ad9f00c74b7cc12b6f892fba66253d47cb1bdfa /arch/x86/kernel/fpu
parent8c0817f4a3188ac5485ce14f96f12a175800b881 (diff)
downloadlinux-79fecc2b7506f29fb91becc65e8788e5ae7eba9f.tar.xz
x86/fpu: Split copy_user_to_xstate() into copy_kernel_to_xstate() & copy_user_to_xstate()
Similar to: x86/fpu: Split copy_xstate_to_user() into copy_xstate_to_kernel() & copy_xstate_to_user() No change in functionality. 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: Eric Biggers <ebiggers3@gmail.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> 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: Yu-cheng Yu <yu-cheng.yu@intel.com> Link: http://lkml.kernel.org/r/20170923130016.21448-12-mingo@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/fpu')
-rw-r--r--arch/x86/kernel/fpu/regset.c10
-rw-r--r--arch/x86/kernel/fpu/xstate.c66
2 files changed, 72 insertions, 4 deletions
diff --git a/arch/x86/kernel/fpu/regset.c b/arch/x86/kernel/fpu/regset.c
index ec1404194b65..cb45dd81d617 100644
--- a/arch/x86/kernel/fpu/regset.c
+++ b/arch/x86/kernel/fpu/regset.c
@@ -134,10 +134,14 @@ int xstateregs_set(struct task_struct *target, const struct user_regset *regset,
fpu__activate_fpstate_write(fpu);
- if (boot_cpu_has(X86_FEATURE_XSAVES))
- ret = copy_user_to_xstate(kbuf, ubuf, xsave);
- else
+ if (boot_cpu_has(X86_FEATURE_XSAVES)) {
+ if (kbuf)
+ ret = copy_kernel_to_xstate(kbuf, ubuf, xsave);
+ else
+ ret = copy_user_to_xstate(kbuf, ubuf, xsave);
+ } else {
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, xsave, 0, -1);
+ }
/*
* In case of failure, mark all states as init:
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 00c3b41c3cf1..1ad25d1b8056 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -1084,7 +1084,71 @@ int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned i
}
/*
- * Convert from a ptrace standard-format buffer to kernel XSAVES format
+ * Convert from a ptrace standard-format kernel buffer to kernel XSAVES format
+ * and copy to the target thread. This is called from xstateregs_set() and
+ * there we check the CPU has XSAVES and a whole standard-sized buffer
+ * exists.
+ */
+int copy_kernel_to_xstate(const void *kbuf, const void __user *ubuf,
+ struct xregs_state *xsave)
+{
+ unsigned int offset, size;
+ int i;
+ u64 xfeatures;
+ u64 allowed_features;
+
+ offset = offsetof(struct xregs_state, header);
+ size = sizeof(xfeatures);
+
+ if (kbuf) {
+ memcpy(&xfeatures, kbuf + offset, size);
+ } else {
+ if (__copy_from_user(&xfeatures, ubuf + offset, size))
+ return -EFAULT;
+ }
+
+ /*
+ * Reject if the user sets any disabled or supervisor features:
+ */
+ allowed_features = xfeatures_mask & ~XFEATURE_MASK_SUPERVISOR;
+
+ if (xfeatures & ~allowed_features)
+ return -EINVAL;
+
+ for (i = 0; i < XFEATURE_MAX; i++) {
+ u64 mask = ((u64)1 << i);
+
+ if (xfeatures & mask) {
+ void *dst = __raw_xsave_addr(xsave, 1 << i);
+
+ offset = xstate_offsets[i];
+ size = xstate_sizes[i];
+
+ if (kbuf) {
+ memcpy(dst, kbuf + offset, size);
+ } else {
+ if (__copy_from_user(dst, ubuf + offset, size))
+ return -EFAULT;
+ }
+ }
+ }
+
+ /*
+ * The state that came in from userspace was user-state only.
+ * Mask all the user states out of 'xfeatures':
+ */
+ xsave->header.xfeatures &= XFEATURE_MASK_SUPERVISOR;
+
+ /*
+ * Add back in the features that came in from userspace:
+ */
+ xsave->header.xfeatures |= xfeatures;
+
+ return 0;
+}
+
+/*
+ * Convert from a ptrace standard-format user-space buffer to kernel XSAVES format
* and copy to the target thread. This is called from xstateregs_set() and
* there we check the CPU has XSAVES and a whole standard-sized buffer
* exists.