[PATCH v2 2/8] powerpc/signal: Add unsafe_copy_{vsx,fpr}_from_user()

[Christopher M. Riedl]

Reuse the "safe" implementation from signal.c except for calling
unsafe_copy_from_user() to copy into a local buffer. Unlike the
unsafe_copy_{vsx,fpr}_to_user() functions the "copy from" functions
cannot use unsafe_get_user() directly to bypass the local buffer since
doing so significantly reduces signal handling performance.

Signed-off-by: Christopher M. Riedl <cmr at codefail.de>
---
 arch/powerpc/kernel/signal.h | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/arch/powerpc/kernel/signal.h b/arch/powerpc/kernel/signal.h
index 2559a681536e..e9aaeac0da37 100644
--- a/arch/powerpc/kernel/signal.h
+++ b/arch/powerpc/kernel/signal.h
@@ -53,6 +53,33 @@ unsigned long copy_ckfpr_from_user(struct task_struct *task, void __user *from);
 				&buf[i], label);\
 } while (0)
 
+#define unsafe_copy_fpr_from_user(task, from, label)	do {		\
+	struct task_struct *__t = task;					\
+	u64 __user *__f = (u64 __user *)from;				\
+	u64 buf[ELF_NFPREG];						\
+	int i;								\
+									\
+	unsafe_copy_from_user(buf, __f, ELF_NFPREG * sizeof(double),	\
+				label);					\
+	for (i = 0; i < ELF_NFPREG - 1; i++)				\
+		__t->thread.TS_FPR(i) = buf[i];				\
+	__t->thread.fp_state.fpscr = buf[i];				\
+} while (0)
+
+#define unsafe_copy_vsx_from_user(task, from, label)	do {		\
+	struct task_struct *__t = task;					\
+	u64 __user *__f = (u64 __user *)from;				\
+	u64 buf[ELF_NVSRHALFREG];					\
+	int i;								\
+									\
+	unsafe_copy_from_user(buf, __f,					\
+				ELF_NVSRHALFREG * sizeof(double),	\
+				label);					\
+	for (i = 0; i < ELF_NVSRHALFREG ; i++)				\
+		__t->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = buf[i];	\
+} while (0)
+
+
 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 #define unsafe_copy_ckfpr_to_user(to, task, label)	do {		\
 	struct task_struct *__t = task;					\
@@ -80,6 +107,10 @@ unsigned long copy_ckfpr_from_user(struct task_struct *task, void __user *from);
 	unsafe_copy_to_user(to, (task)->thread.fp_state.fpr,	\
 			    ELF_NFPREG * sizeof(double), label)
 
+#define unsafe_copy_fpr_from_user(task, from, label)		\
+	unsafe_copy_from_user((task)->thread.fp_state.fpr, from	\
+			    ELF_NFPREG * sizeof(double), label)
+
 static inline unsigned long
 copy_fpr_to_user(void __user *to, struct task_struct *task)
 {
@@ -115,6 +146,8 @@ copy_ckfpr_from_user(struct task_struct *task, void __user *from)
 #else
 #define unsafe_copy_fpr_to_user(to, task, label) do { } while (0)
 
+#define unsafe_copy_fpr_from_user(task, from, label) do { } while (0)
+
 static inline unsigned long
 copy_fpr_to_user(void __user *to, struct task_struct *task)
 {
-- 
2.29.0