x86/fpu: Remove 'kbuf' parameter from the copy_user_to_xstate() API

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/20170923130016.21448-14-mingo@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 5 insertions, 14 deletions

diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 71cc8d367fdd..b1f3e4dae2e3 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -1142,8 +1142,7 @@ int copy_kernel_to_xstate(const void *kbuf, struct xregs_state *xsave)
  * there we check the CPU has XSAVES and a whole standard-sized buffer
  * exists.
  */
-int copy_user_to_xstate(const void *kbuf, const void __user *ubuf,
-                     struct xregs_state *xsave)
+int copy_user_to_xstate(const void __user *ubuf, struct xregs_state *xsave)
 {
         unsigned int offset, size;
         int i;
@@ -1153,12 +1152,8 @@ int copy_user_to_xstate(const void *kbuf, const void __user *ubuf,
         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;
-        }
+        if (__copy_from_user(&xfeatures, ubuf + offset, size))
+                return -EFAULT;
 
         /*
          * Reject if the user sets any disabled or supervisor features:
@@ -1177,12 +1172,8 @@ int copy_user_to_xstate(const void *kbuf, const void __user *ubuf,
                         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;
-                        }
+                        if (__copy_from_user(dst, ubuf + offset, size))
+                                return -EFAULT;
                 }
         }