x86/fpu: Remove 'kbuf' parameter from the copy_xstate_to_user() APIs

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: 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/20170923130016.21448-5-mingo@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h
index c762574..65bd68c 100644 (file)
--- 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 34e74ad..fd6dbdd 100644 (file)
--- 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 71d3bda..2d8f334 100644 (file)
--- 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;