Merge tag 'powerpc-3.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux

[firefly-linux-kernel-4.4.55.git] / arch / powerpc / kernel / ftrace.c

diff --git a/arch/powerpc/kernel/ftrace.c b/arch/powerpc/kernel/ftrace.c
index 390311c0f03d0dd6b1775ebc79526d67519176ec..44d4d8eb3c85c6a8e845b9048e0276842122a3f0 100644 (file)
--- a/arch/powerpc/kernel/ftrace.c
+++ b/arch/powerpc/kernel/ftrace.c
@@ -449,7 +449,7 @@ void ftrace_replace_code(int enable)
                rec = ftrace_rec_iter_record(iter);
                ret = __ftrace_replace_code(rec, enable);
                if (ret) {
-                       ftrace_bug(ret, rec->ip);
+                       ftrace_bug(ret, rec);
                        return;
                }
        }
@@ -510,79 +510,36 @@ 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.
+ * in current thread info. Return the address we want to divert to.
  */
-void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
+unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip)
 {
-       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;
+               goto out;
 
        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);
+               goto out;
 
-       /*
-        * Protect against fault, even if it shouldn't
-        * happen. This tool is too much intrusive to
-        * ignore such a protection.
-        */
-       asm volatile(
-               "1: " PPC_LL "%[old], 0(%[parent])\n"
-               "2: " PPC_STL "%[return_hooker], 0(%[parent])\n"
-               "   li %[faulted], 0\n"
-               "3:\n"
-
-               ".section .fixup, \"ax\"\n"
-               "4: li %[faulted], 1\n"
-               "   b 3b\n"
-               ".previous\n"
-
-               ".section __ex_table,\"a\"\n"
-                       PPC_LONG_ALIGN "\n"
-                       PPC_LONG "1b,4b\n"
-                       PPC_LONG "2b,4b\n"
-               ".previous"
-
-               : [old] "=&r" (old), [faulted] "=r" (faulted)
-               : [parent] "r" (parent), [return_hooker] "r" (return_hooker)
-               : "memory"
-       );
-
-       if (unlikely(faulted)) {
-               ftrace_graph_stop();
-               WARN_ON(1);
-               return;
-       }
+       return_hooker = ppc_function_entry(return_to_handler);
 
-       trace.func = self_addr;
+       trace.func = ip;
        trace.depth = current->curr_ret_stack + 1;
 
        /* Only trace if the calling function expects to */
-       if (!ftrace_graph_entry(&trace)) {
-               *parent = old;
-               return;
-       }
+       if (!ftrace_graph_entry(&trace))
+               goto out;
+
+       if (ftrace_push_return_trace(parent, ip, &trace.depth, 0) == -EBUSY)
+               goto out;
 
-       if (ftrace_push_return_trace(old, self_addr, &trace.depth, 0) == -EBUSY)
-               *parent = old;
+       parent = return_hooker;
+out:
+       return parent;
 }
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */