[tip:x86/fpu] x86/fpu: Remove 'ubuf' parameter from the copy_kernel_to_xstate() API

[tip-bot for Ingo Molnar]

Commit-ID:  59dffa4edba1f15b2bfdbe608aca1efe664c674c
Gitweb:     http://git.kernel.org/tip/59dffa4edba1f15b2bfdbe608aca1efe664c674c
Author:     Ingo Molnar <mingo@xxxxxxxxxx>
AuthorDate: Sat, 23 Sep 2017 14:59:55 +0200
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Sun, 24 Sep 2017 13:04:33 +0200

x86/fpu: Remove 'ubuf' parameter from the copy_kernel_to_xstate() API

No change in functionality.

Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Eric Biggers <ebiggers3@xxxxxxxxx>
Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Yu-cheng Yu <yu-cheng.yu@xxxxxxxxx>
Link: http://lkml.kernel.org/r/20170923130016.21448-13-mingo@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 arch/x86/include/asm/fpu/xstate.h |  2 +-
 arch/x86/kernel/fpu/regset.c      |  2 +-
 arch/x86/kernel/fpu/xstate.c      | 17 +++--------------
 3 files changed, 5 insertions(+), 16 deletions(-)

diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h
index 79af79d..f10889b 100644
--- a/arch/x86/include/asm/fpu/xstate.h
+++ b/arch/x86/include/asm/fpu/xstate.h
@@ -50,6 +50,6 @@ const void *get_xsave_field_ptr(int xstate_field);
 int using_compacted_format(void);
 int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int offset, unsigned int size);
 int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned int offset, unsigned int size);
-int copy_kernel_to_xstate(const void *kbuf, const void __user *ubuf, struct xregs_state *xsave);
+int copy_kernel_to_xstate(const void *kbuf, struct xregs_state *xsave);
 int copy_user_to_xstate(const void *kbuf, const void __user *ubuf, struct xregs_state *xsave);
 #endif
diff --git a/arch/x86/kernel/fpu/regset.c b/arch/x86/kernel/fpu/regset.c
index cb45dd8..785302c 100644
--- a/arch/x86/kernel/fpu/regset.c
+++ b/arch/x86/kernel/fpu/regset.c
@@ -136,7 +136,7 @@ int xstateregs_set(struct task_struct *target, const struct user_regset *regset,
 
 	if (boot_cpu_has(X86_FEATURE_XSAVES)) {
 		if (kbuf)
-			ret = copy_kernel_to_xstate(kbuf, ubuf, xsave);
+			ret = copy_kernel_to_xstate(kbuf, xsave);
 		else
 			ret = copy_user_to_xstate(kbuf, ubuf, xsave);
 	} else {
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 1ad25d1..71cc8d3 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -1089,8 +1089,7 @@ int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned i
  * 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)
+int copy_kernel_to_xstate(const void *kbuf, struct xregs_state *xsave)
 {
 	unsigned int offset, size;
 	int i;
@@ -1100,12 +1099,7 @@ int copy_kernel_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;
-	}
+	memcpy(&xfeatures, kbuf + offset, size);
 
 	/*
 	 * Reject if the user sets any disabled or supervisor features:
@@ -1124,12 +1118,7 @@ int copy_kernel_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;
-			}
+			memcpy(dst, kbuf + offset, size);
 		}
 	}