diff options
author | Ingo Molnar <mingo@kernel.org> | 2017-09-23 15:59:54 +0300 |
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committer | Ingo Molnar <mingo@kernel.org> | 2017-09-24 14:04:32 +0300 |
commit | 79fecc2b7506f29fb91becc65e8788e5ae7eba9f (patch) | |
tree | 5ad9f00c74b7cc12b6f892fba66253d47cb1bdfa /arch/x86/kernel/fpu | |
parent | 8c0817f4a3188ac5485ce14f96f12a175800b881 (diff) | |
download | linux-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.c | 10 | ||||
-rw-r--r-- | arch/x86/kernel/fpu/xstate.c | 66 |
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. |