[PATCH 04/33] x86/fpu: Remove 'kbuf' parameter from the copy_xstate_to_user() APIs

From: Ingo Molnar
Date: Sat Sep 23 2017 - 09:01:00 EST


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

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

Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Cc: H. Peter Anvin <hpa@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>
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 | 25 +++++++------------------
3 files changed, 9 insertions(+), 20 deletions(-)

diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h
index c762574a245f..65bd68c30cd0 100644
--- a/arch/x86/include/asm/fpu/xstate.h
+++ b/arch/x86/include/asm/fpu/xstate.h
@@ -49,7 +49,7 @@ 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, 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_xstate_to_user(unsigned int pos, unsigned int count, void __user *ubuf, 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 34e74adf9d5d..fd6dbdd8fde6 100644
--- a/arch/x86/kernel/fpu/regset.c
+++ b/arch/x86/kernel/fpu/regset.c
@@ -95,7 +95,7 @@ int xstateregs_get(struct task_struct *target, const struct user_regset *regset,
if (kbuf)
ret = copy_xstate_to_kernel(pos, count, kbuf, xsave);
else
- ret = copy_xstate_to_user(pos, count, kbuf, ubuf, xsave);
+ ret = copy_xstate_to_user(pos, count, ubuf, xsave);
} else {
fpstate_sanitize_xstate(fpu);
/*
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 71d3bda2b898..2d8f3344875d 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -1011,10 +1011,7 @@ int copy_xstate_to_kernel(unsigned int pos, unsigned int count, void *kbuf, stru
}

static inline int
-__copy_xstate_to_user(unsigned int pos, unsigned int count,
- void *kbuf, void __user *ubuf,
- const void *data, const int start_pos,
- const int end_pos)
+__copy_xstate_to_user(unsigned int pos, unsigned int count, void __user *ubuf, const void *data, const int start_pos, const int end_pos)
{
if ((count == 0) || (pos < start_pos))
return 0;
@@ -1022,12 +1019,8 @@ __copy_xstate_to_user(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;
- }
+ if (__copy_to_user(ubuf + pos, data, copy))
+ return -EFAULT;
}
return 0;
}
@@ -1038,8 +1031,7 @@ __copy_xstate_to_user(unsigned int pos, unsigned int count,
* zero. This is called from xstateregs_get() and there we check the CPU
* has XSAVES.
*/
-int copy_xstate_to_user(unsigned int pos, unsigned int count, void *kbuf,
- void __user *ubuf, struct xregs_state *xsave)
+int copy_xstate_to_user(unsigned int pos, unsigned int count, void __user *ubuf, struct xregs_state *xsave)
{
unsigned int offset, size;
int ret, i;
@@ -1064,8 +1056,7 @@ int copy_xstate_to_user(unsigned int pos, unsigned int count, void *kbuf,
offset = offsetof(struct xregs_state, header);
size = sizeof(header);

- ret = __copy_xstate_to_user(offset, size, kbuf, ubuf, &header, 0, count);
-
+ ret = __copy_xstate_to_user(offset, size, ubuf, &header, 0, count);
if (ret)
return ret;

@@ -1079,8 +1070,7 @@ int copy_xstate_to_user(unsigned int pos, unsigned int count, void *kbuf,
offset = xstate_offsets[i];
size = xstate_sizes[i];

- ret = __copy_xstate_to_user(offset, size, kbuf, ubuf, src, 0, count);
-
+ ret = __copy_xstate_to_user(offset, size, ubuf, src, 0, count);
if (ret)
return ret;

@@ -1096,8 +1086,7 @@ int copy_xstate_to_user(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_user(offset, size, kbuf, ubuf, xstate_fx_sw_bytes, 0, count);
-
+ ret = __copy_xstate_to_user(offset, size, ubuf, xstate_fx_sw_bytes, 0, count);
if (ret)
return ret;

--
2.11.0