1 files changed, 57 insertions, 19 deletions

diff --git a/arch/x86/um/ptrace.c b/arch/x86/um/ptrace.c
index 57c504fd5626..3275870330fe 100644
--- a/arch/x86/um/ptrace.c
+++ b/arch/x86/um/ptrace.c
@@ -25,7 +25,8 @@ static inline unsigned short twd_i387_to_fxsr(unsigned short twd)
 	return tmp;
 }
 
-static inline unsigned long twd_fxsr_to_i387(struct user_fxsr_struct *fxsave)
+static inline unsigned long
+twd_fxsr_to_i387(const struct user_fxsr_struct *fxsave)
 {
 	struct _fpxreg *st = NULL;
 	unsigned long twd = (unsigned long) fxsave->twd;
@@ -69,12 +70,16 @@ static inline unsigned long twd_fxsr_to_i387(struct user_fxsr_struct *fxsave)
 	return ret;
 }
 
-/* Get/set the old 32bit i387 registers (pre-FPX) */
-static int fpregs_legacy_get(struct task_struct *target,
-			     const struct user_regset *regset,
-			     struct membuf to)
+/*
+ * Get/set the old 32bit i387 registers (pre-FPX)
+ *
+ * We provide simple wrappers for mcontext.c, they are only defined locally
+ * because mcontext.c is userspace facing and needs to a different definition
+ * of the structures.
+ */
+static int _um_i387_from_fxsr(struct membuf to,
+			      const struct user_fxsr_struct *fxsave)
 {
-	struct user_fxsr_struct *fxsave = (void *)target->thread.regs.regs.fp;
 	int i;
 
 	membuf_store(&to, (unsigned long)fxsave->cwd | 0xffff0000ul);
@@ -91,23 +96,36 @@ static int fpregs_legacy_get(struct task_struct *target,
 	return 0;
 }
 
-static int fpregs_legacy_set(struct task_struct *target,
+int um_i387_from_fxsr(struct user_i387_struct *i387,
+		      const struct user_fxsr_struct *fxsave);
+
+int um_i387_from_fxsr(struct user_i387_struct *i387,
+		      const struct user_fxsr_struct *fxsave)
+{
+	struct membuf to = {
+		.p = i387,
+		.left = sizeof(*i387),
+	};
+
+	return _um_i387_from_fxsr(to, fxsave);
+}
+
+static int fpregs_legacy_get(struct task_struct *target,
 			     const struct user_regset *regset,
-			     unsigned int pos, unsigned int count,
-			     const void *kbuf, const void __user *ubuf)
+			     struct membuf to)
 {
 	struct user_fxsr_struct *fxsave = (void *)target->thread.regs.regs.fp;
-	const struct user_i387_struct *from;
-	struct user_i387_struct buf;
-	int i;
 
-	if (ubuf) {
-		if (copy_from_user(&buf, ubuf, sizeof(buf)))
-			return -EFAULT;
-		from = &buf;
-	} else {
-		from = kbuf;
-	}
+	return _um_i387_from_fxsr(to, fxsave);
+}
+
+int um_fxsr_from_i387(struct user_fxsr_struct *fxsave,
+		      const struct user_i387_struct *from);
+
+int um_fxsr_from_i387(struct user_fxsr_struct *fxsave,
+		      const struct user_i387_struct *from)
+{
+	int i;
 
 	fxsave->cwd = (unsigned short)(from->cwd & 0xffff);
 	fxsave->swd = (unsigned short)(from->swd & 0xffff);
@@ -125,6 +143,26 @@ static int fpregs_legacy_set(struct task_struct *target,
 
 	return 0;
 }
+
+static int fpregs_legacy_set(struct task_struct *target,
+			     const struct user_regset *regset,
+			     unsigned int pos, unsigned int count,
+			     const void *kbuf, const void __user *ubuf)
+{
+	struct user_fxsr_struct *fxsave = (void *)target->thread.regs.regs.fp;
+	const struct user_i387_struct *from;
+	struct user_i387_struct buf;
+
+	if (ubuf) {
+		if (copy_from_user(&buf, ubuf, sizeof(buf)))
+			return -EFAULT;
+		from = &buf;
+	} else {
+		from = kbuf;
+	}
+
+	return um_fxsr_from_i387(fxsave, &buf);
+}
 #endif
 
 static int genregs_get(struct task_struct *target,