powerpc/signal: Call get_tm_stackpointer() from get_sigframe()

Instead of calling get_tm_stackpointer() from the caller, call it
directly from get_sigframe(). This avoids a double call and
allows get_tm_stackpointer() to become static and be inlined
into get_sigframe() by GCC.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/abfdc105b8b28c4eb3ab9a26297d17f302b600ea.1597770847.git.christophe.leroy@csgroup.eu

arch/powerpc/kernel/signal.c

@@ -144,10 +144,13 @@ int show_unhandled_signals = 1;
 /*
  * Allocate space for the signal frame
  */
-void __user *get_sigframe(struct ksignal *ksig, unsigned long sp,
+static unsigned long get_tm_stackpointer(struct task_struct *tsk);
+
+void __user *get_sigframe(struct ksignal *ksig, struct task_struct *tsk,
 			  size_t frame_size, int is_32)
 {
         unsigned long oldsp, newsp;
+	unsigned long sp = get_tm_stackpointer(tsk);
 
         /* Default to using normal stack */
 	if (is_32)
@@ -300,7 +303,7 @@ void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags)
 	user_enter();
 }
 
-unsigned long get_tm_stackpointer(struct task_struct *tsk)
+static unsigned long get_tm_stackpointer(struct task_struct *tsk)
 {
 	/* When in an active transaction that takes a signal, we need to be
 	 * careful with the stack.  It's possible that the stack has moved back

arch/powerpc/kernel/signal.h

@@ -10,7 +10,7 @@
 #ifndef _POWERPC_ARCH_SIGNAL_H
 #define _POWERPC_ARCH_SIGNAL_H
 
-extern void __user *get_sigframe(struct ksignal *ksig, unsigned long sp,
+void __user *get_sigframe(struct ksignal *ksig, struct task_struct *tsk,
 			  size_t frame_size, int is_32);
 
 extern int handle_signal32(struct ksignal *ksig, sigset_t *oldset,
@@ -19,8 +19,6 @@ extern int handle_signal32(struct ksignal *ksig, sigset_t *oldset,
 extern int handle_rt_signal32(struct ksignal *ksig, sigset_t *oldset,
 			      struct task_struct *tsk);
 
-extern unsigned long get_tm_stackpointer(struct task_struct *tsk);
-
 #ifdef CONFIG_VSX
 extern unsigned long copy_vsx_to_user(void __user *to,
 				      struct task_struct *task);

arch/powerpc/kernel/signal_32.c

@@ -766,7 +766,7 @@ int handle_rt_signal32(struct ksignal *ksig, sigset_t *oldset,
 
 	/* Set up Signal Frame */
 	/* Put a Real Time Context onto stack */
-	rt_sf = get_sigframe(ksig, get_tm_stackpointer(tsk), sizeof(*rt_sf), 1);
+	rt_sf = get_sigframe(ksig, tsk, sizeof(*rt_sf), 1);
 	addr = rt_sf;
 	if (!access_ok(rt_sf, sizeof(*rt_sf)))
 		goto badframe;
@@ -1226,7 +1226,7 @@ int handle_signal32(struct ksignal *ksig, sigset_t *oldset,
 #endif
 
 	/* Set up Signal Frame */
-	frame = get_sigframe(ksig, get_tm_stackpointer(tsk), sizeof(*frame), 1);
+	frame = get_sigframe(ksig, tsk, sizeof(*frame), 1);
 	if (!access_ok(frame, sizeof(*frame)))
 		goto badframe;
 	sc = (struct sigcontext __user *) &frame->sctx;

arch/powerpc/kernel/signal_64.c

@@ -822,7 +822,7 @@ int handle_rt_signal64(struct ksignal *ksig, sigset_t *set,
 	unsigned long msr = regs->msr;
 #endif
 
-	frame = get_sigframe(ksig, get_tm_stackpointer(tsk), sizeof(*frame), 0);
+	frame = get_sigframe(ksig, tsk, sizeof(*frame), 0);
 	if (!access_ok(frame, sizeof(*frame)))
 		goto badframe;