[tip:x86/fpu] x86/fpu: Remove 'ubuf' parameter from the copy_xstate_to_kernel() APIs

[tip-bot for Ingo Molnar]

Commit-ID:  4d981cf2d96f29cdfa7d4972c8b377fe7baa9c4c
Gitweb:     http://git.kernel.org/tip/4d981cf2d96f29cdfa7d4972c8b377fe7baa9c4c
Author:     Ingo Molnar <mingo@xxxxxxxxxx>
AuthorDate: Sat, 23 Sep 2017 14:59:46 +0200
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Sun, 24 Sep 2017 13:04:31 +0200

x86/fpu: Remove 'ubuf' parameter from the copy_xstate_to_kernel() APIs

The 'ubuf' parameter is unused in the _kernel() side of the API, remove it.

This simplifies the code and makes it easier to think about.

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/20170923130016.21448-4-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      | 21 ++++++---------------
 3 files changed, 8 insertions(+), 17 deletions(-)

diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h
index 92dc8ca..c762574 100644
--- a/arch/x86/include/asm/fpu/xstate.h
+++ b/arch/x86/include/asm/fpu/xstate.h
@@ -48,7 +48,7 @@ void fpu__xstate_clear_all_cpu_caps(void);
 void *get_xsave_addr(struct xregs_state *xsave, int xstate);
 const void *get_xsave_field_ptr(int xstate_field);
 int using_compacted_format(void);
-int copy_xstate_to_kernel(unsigned int pos, unsigned int count, void *kbuf, void __user *ubuf, struct xregs_state *xsave);
+int copy_xstate_to_kernel(unsigned int pos, unsigned int count, void *kbuf, struct xregs_state *xsave);
 int copy_xstate_to_user(unsigned int pos, unsigned int count, void *kbuf, void __user *ubuf, struct xregs_state *xsave);
 int copy_user_to_xstate(const void *kbuf, const void __user *ubuf,
 		     struct xregs_state *xsave);
diff --git a/arch/x86/kernel/fpu/regset.c b/arch/x86/kernel/fpu/regset.c
index b6d12d6..34e74ad 100644
--- a/arch/x86/kernel/fpu/regset.c
+++ b/arch/x86/kernel/fpu/regset.c
@@ -93,7 +93,7 @@ int xstateregs_get(struct task_struct *target, const struct user_regset *regset,
 
 	if (using_compacted_format()) {
 		if (kbuf)
-			ret = copy_xstate_to_kernel(pos, count, kbuf, ubuf, xsave);
+			ret = copy_xstate_to_kernel(pos, count, kbuf, xsave);
 		else
 			ret = copy_xstate_to_user(pos, count, kbuf, ubuf, xsave);
 	} else {
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 3856153..71d3bda 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -926,7 +926,7 @@ int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
  */
 static inline int
 __copy_xstate_to_kernel(unsigned int pos, unsigned int count,
-			void *kbuf, void __user *ubuf,
+			void *kbuf,
 			const void *data, const int start_pos,
 			const int end_pos)
 {
@@ -936,12 +936,7 @@ __copy_xstate_to_kernel(unsigned int pos, unsigned int count,
 	if (end_pos < 0 || pos < end_pos) {
 		unsigned int copy = (end_pos < 0 ? count : min(count, end_pos - pos));
 
-		if (kbuf) {
-			memcpy(kbuf + pos, data, copy);
-		} else {
-			if (__copy_to_user(ubuf + pos, data, copy))
-				return -EFAULT;
-		}
+		memcpy(kbuf + pos, data, copy);
 	}
 	return 0;
 }
@@ -953,8 +948,7 @@ __copy_xstate_to_kernel(unsigned int pos, unsigned int count,
  * It supports partial copy but pos always starts from zero. This is called
  * from xstateregs_get() and there we check the CPU has XSAVES.
  */
-int copy_xstate_to_kernel(unsigned int pos, unsigned int count, void *kbuf,
-			void __user *ubuf, struct xregs_state *xsave)
+int copy_xstate_to_kernel(unsigned int pos, unsigned int count, void *kbuf, struct xregs_state *xsave)
 {
 	unsigned int offset, size;
 	int ret, i;
@@ -979,8 +973,7 @@ int copy_xstate_to_kernel(unsigned int pos, unsigned int count, void *kbuf,
 	offset = offsetof(struct xregs_state, header);
 	size = sizeof(header);
 
-	ret = __copy_xstate_to_kernel(offset, size, kbuf, ubuf, &header, 0, count);
-
+	ret = __copy_xstate_to_kernel(offset, size, kbuf, &header, 0, count);
 	if (ret)
 		return ret;
 
@@ -994,8 +987,7 @@ int copy_xstate_to_kernel(unsigned int pos, unsigned int count, void *kbuf,
 			offset = xstate_offsets[i];
 			size = xstate_sizes[i];
 
-			ret = __copy_xstate_to_kernel(offset, size, kbuf, ubuf, src, 0, count);
-
+			ret = __copy_xstate_to_kernel(offset, size, kbuf, src, 0, count);
 			if (ret)
 				return ret;
 
@@ -1011,8 +1003,7 @@ int copy_xstate_to_kernel(unsigned int pos, unsigned int count, void *kbuf,
 	offset = offsetof(struct fxregs_state, sw_reserved);
 	size = sizeof(xstate_fx_sw_bytes);
 
-	ret = __copy_xstate_to_kernel(offset, size, kbuf, ubuf, xstate_fx_sw_bytes, 0, count);
-
+	ret = __copy_xstate_to_kernel(offset, size, kbuf, xstate_fx_sw_bytes, 0, count);
 	if (ret)
 		return ret;