powerpc/ftrace: Remove mod_return_to_handler

mod_return_to_handler is the same as return_to_handler, except
it handles the change of the TOC (r2). Add this into
return_to_handler and remove mod_return_to_handler.

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

3 files changed, 4 insertions, 43 deletions

diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index 0905c8da90f1..66f7ed32848f 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -1241,28 +1241,6 @@ _GLOBAL(ftrace_graph_caller)
 
 _GLOBAL(return_to_handler)
         /* need to save return values */
-        std     r4,  -24(r1)
-        std     r3,  -16(r1)
-        std     r31, -8(r1)
-        mr      r31, r1
-        stdu    r1, -112(r1)
-
-        bl      ftrace_return_to_handler
-        nop
-
-        /* return value has real return address */
-        mtlr    r3
-
-        ld      r1, 0(r1)
-        ld      r4,  -24(r1)
-        ld      r3,  -16(r1)
-        ld      r31, -8(r1)
-
-        /* Jump back to real return address */
-        blr
-
-_GLOBAL(mod_return_to_handler)
-        /* need to save return values */
         std     r4,  -32(r1)
         std     r3,  -24(r1)
         /* save TOC */
@@ -1272,7 +1250,7 @@ _GLOBAL(mod_return_to_handler)
         stdu    r1, -112(r1)
 
         /*
-         * We are in a module using the module's TOC.
+         * We might be called from a module.
          * Switch to our TOC to run inside the core kernel.
          */
         ld      r2, PACATOC(r13)
diff --git a/arch/powerpc/kernel/ftrace.c b/arch/powerpc/kernel/ftrace.c
index 390311c0f03d..abf79213c356 100644
--- a/arch/powerpc/kernel/ftrace.c
+++ b/arch/powerpc/kernel/ftrace.c
@@ -510,10 +510,6 @@ int ftrace_disable_ftrace_graph_caller(void)
 }
 #endif /* CONFIG_DYNAMIC_FTRACE */
 
-#ifdef CONFIG_PPC64
-extern void mod_return_to_handler(void);
-#endif
-
 /*
  * Hook the return address and push it in the stack of return addrs
  * in current thread info.
@@ -523,7 +519,7 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
         unsigned long old;
         int faulted;
         struct ftrace_graph_ent trace;
-        unsigned long return_hooker = (unsigned long)&return_to_handler;
+        unsigned long return_hooker;
 
         if (unlikely(ftrace_graph_is_dead()))
                 return;
@@ -531,13 +527,7 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
         if (unlikely(atomic_read(&current->tracing_graph_pause)))
                 return;
 
-#ifdef CONFIG_PPC64
-        /* non core kernel code needs to save and restore the TOC */
-        if (REGION_ID(self_addr) != KERNEL_REGION_ID)
-                return_hooker = (unsigned long)&mod_return_to_handler;
-#endif
-
-        return_hooker = ppc_function_entry((void *)return_hooker);
+        return_hooker = ppc_function_entry(return_to_handler);
 
         /*
          * Protect against fault, even if it shouldn't
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 8c2691e445bd..f6b82152e7aa 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1527,13 +1527,6 @@ void show_stack(struct task_struct *tsk, unsigned long *stack)
         int curr_frame = current->curr_ret_stack;
         extern void return_to_handler(void);
         unsigned long rth = (unsigned long)return_to_handler;
-        unsigned long mrth = -1;
-#ifdef CONFIG_PPC64
-        extern void mod_return_to_handler(void);
-        rth = *(unsigned long *)rth;
-        mrth = (unsigned long)mod_return_to_handler;
-        mrth = *(unsigned long *)mrth;
-#endif
 #endif
 
         sp = (unsigned long) stack;
@@ -1558,7 +1551,7 @@ void show_stack(struct task_struct *tsk, unsigned long *stack)
                 if (!firstframe || ip != lr) {
                         printk("["REG"] ["REG"] %pS", sp, ip, (void *)ip);
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
-                        if ((ip == rth || ip == mrth) && curr_frame >= 0) {
+                        if ((ip == rth) && curr_frame >= 0) {
                                 printk(" (%pS)",
                                        (void *)current->ret_stack[curr_frame].ret);
                                 curr_frame--;