powerpc: Move part of giveup_vsx into c

Move the MSR modification into c. Removing it from the assembly
function will allow us to avoid costly MSR writes by batching them
up.

Check the FP and VMX bits before calling the relevant giveup_*()
function. This makes giveup_vsx() and flush_vsx_to_thread() perform
more like their sister functions, and allows us to use
flush_vsx_to_thread() in the signal code.

Move the check_if_tm_restore_required() check in.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

4 files changed, 23 insertions, 19 deletions

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 6bcf82bed610..0cb627662ded 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -205,6 +205,25 @@ EXPORT_SYMBOL_GPL(flush_altivec_to_thread);
 #endif /* CONFIG_ALTIVEC */
 
 #ifdef CONFIG_VSX
+void giveup_vsx(struct task_struct *tsk)
+{
+        u64 oldmsr = mfmsr();
+        u64 newmsr;
+
+        check_if_tm_restore_required(tsk);
+
+        newmsr = oldmsr | (MSR_FP|MSR_VEC|MSR_VSX);
+        if (oldmsr != newmsr)
+                mtmsr_isync(newmsr);
+
+        if (tsk->thread.regs->msr & MSR_FP)
+                __giveup_fpu(tsk);
+        if (tsk->thread.regs->msr & MSR_VEC)
+                __giveup_altivec(tsk);
+        __giveup_vsx(tsk);
+}
+EXPORT_SYMBOL(giveup_vsx);
+
 void enable_kernel_vsx(void)
 {
         WARN_ON(preemptible());
@@ -220,15 +239,6 @@ void enable_kernel_vsx(void)
 }
 EXPORT_SYMBOL(enable_kernel_vsx);
 
-void giveup_vsx(struct task_struct *tsk)
-{
-        check_if_tm_restore_required(tsk);
-        giveup_fpu(tsk);
-        giveup_altivec(tsk);
-        __giveup_vsx(tsk);
-}
-EXPORT_SYMBOL(giveup_vsx);
-
 void flush_vsx_to_thread(struct task_struct *tsk)
 {
         if (tsk->thread.regs) {
diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index 3cd7a32c8ff4..4022cbb7e2d6 100644
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -458,7 +458,7 @@ static int save_user_regs(struct pt_regs *regs, struct mcontext __user *frame,
          * contains valid data
          */
         if (current->thread.used_vsr && ctx_has_vsx_region) {
-                __giveup_vsx(current);
+                flush_vsx_to_thread(current);
                 if (copy_vsx_to_user(&frame->mc_vsregs, current))
                         return 1;
                 msr |= MSR_VSX;
@@ -606,7 +606,7 @@ static int save_tm_user_regs(struct pt_regs *regs,
          * contains valid data
          */
         if (current->thread.used_vsr) {
-                __giveup_vsx(current);
+                flush_vsx_to_thread(current);
                 if (copy_vsx_to_user(&frame->mc_vsregs, current))
                         return 1;
                 if (msr & MSR_VSX) {
diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
index 6f2b555516e6..3b2339912911 100644
--- a/arch/powerpc/kernel/signal_64.c
+++ b/arch/powerpc/kernel/signal_64.c
@@ -147,7 +147,7 @@ static long setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
          * VMX data.
          */
         if (current->thread.used_vsr && ctx_has_vsx_region) {
-                __giveup_vsx(current);
+                flush_vsx_to_thread(current);
                 v_regs += ELF_NVRREG;
                 err |= copy_vsx_to_user(v_regs, current);
                 /* set MSR_VSX in the MSR value in the frame to
@@ -270,7 +270,7 @@ static long setup_tm_sigcontexts(struct sigcontext __user *sc,
          * VMX data.
          */
         if (current->thread.used_vsr) {
-                __giveup_vsx(current);
+                flush_vsx_to_thread(current);
                 v_regs += ELF_NVRREG;
                 tm_v_regs += ELF_NVRREG;
 
diff --git a/arch/powerpc/kernel/vector.S b/arch/powerpc/kernel/vector.S
index 6e925b40a484..98675b08efe2 100644
--- a/arch/powerpc/kernel/vector.S
+++ b/arch/powerpc/kernel/vector.S
@@ -177,14 +177,8 @@ _GLOBAL(load_up_vsx)
  * __giveup_vsx(tsk)
  * Disable VSX for the task given as the argument.
  * Does NOT save vsx registers.
- * Enables the VSX for use in the kernel on return.
  */
 _GLOBAL(__giveup_vsx)
-        mfmsr   r5
-        oris    r5,r5,MSR_VSX@h
-        mtmsrd  r5                      /* enable use of VSX now */
-        isync
-
         addi    r3,r3,THREAD            /* want THREAD of task */
         ld      r5,PT_REGS(r3)
         cmpdi   0,r5,0