linux-kernel - [PATCH 13/14] x86/fpu: Remove 'kbuf' parameter from the copy_user_to

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Message-Id: <1485426179-13681-14-git-send-email-mingo@kernel.org>
Date:   Thu, 26 Jan 2017 11:22:58 +0100
From:   Ingo Molnar <mingo@...nel.org>
To:     linux-kernel@...r.kernel.org
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Andy Lutomirski <luto@...capital.net>,
        Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Fenghua Yu <fenghua.yu@...el.com>,
        "H . Peter Anvin" <hpa@...or.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Oleg Nesterov <oleg@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Rik van Riel <riel@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Yu-cheng Yu <yu-cheng.yu@...el.com>
Subject: [PATCH 13/14] x86/fpu: Remove 'kbuf' parameter from the copy_user_to_xstate() API

No change in functionality.

Cc: Andy Lutomirski <luto@...nel.org>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Dave Hansen <dave.hansen@...ux.intel.com>
Cc: Fenghua Yu <fenghua.yu@...el.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Oleg Nesterov <oleg@...hat.com>
Cc: Rik van Riel <riel@...hat.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@...el.com>
Cc: Fenghua Yu <fenghua.yu@...el.com>
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/include/asm/fpu/xstate.h |  2 +-
 arch/x86/kernel/fpu/regset.c      |  2 +-
 arch/x86/kernel/fpu/signal.c      | 11 ++++-------
 arch/x86/kernel/fpu/xstate.c      | 19 +++++--------------
 4 files changed, 11 insertions(+), 23 deletions(-)

diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h
index f10889bc0c88..4ceb90740d80 100644
--- a/arch/x86/include/asm/fpu/xstate.h
+++ b/arch/x86/include/asm/fpu/xstate.h
@@ -51,5 +51,5 @@ 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, struct xregs_state *xsave);
-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);
 #endif
diff --git a/arch/x86/kernel/fpu/regset.c b/arch/x86/kernel/fpu/regset.c
index ffcbed521fd9..f0c4a5ec7044 100644
--- a/arch/x86/kernel/fpu/regset.c
+++ b/arch/x86/kernel/fpu/regset.c
@@ -137,7 +137,7 @@ int xstateregs_set(struct task_struct *target, const struct user_regset *regset,
 		if (kbuf)
 			ret = copy_kernel_to_xstate(kbuf, xsave);
 		else
-			ret = copy_user_to_xstate(kbuf, ubuf, xsave);
+			ret = copy_user_to_xstate(ubuf, xsave);
 	} else {
 		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, xsave, 0, -1);
 	}
diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
index b1fe9a1fc4e0..2c685b492fd6 100644
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -323,13 +323,10 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
 		 */
 		fpu__drop(fpu);
 
-		if (using_compacted_format()) {
-			err = copy_user_to_xstate(NULL, buf_fx,
-					       &fpu->state.xsave);
-		} else {
-			err = __copy_from_user(&fpu->state.xsave,
-					       buf_fx, state_size);
-		}
+		if (using_compacted_format())
+			err = copy_user_to_xstate(buf_fx, &fpu->state.xsave);
+		else
+			err = __copy_from_user(&fpu->state.xsave, buf_fx, state_size);
 
 		if (err || __copy_from_user(&env, buf, sizeof(env))) {
 			fpstate_init(&fpu->state);
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 3b89b2784665..1402a5496654 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -1141,8 +1141,7 @@ 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;
@@ -1152,12 +1151,8 @@ 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:
@@ -1176,12 +1171,8 @@ 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;
 		}
 	}
 
-- 
2.7.4