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Diffstat (limited to 'arch/powerpc/kernel/ftrace.c')
-rw-r--r--arch/powerpc/kernel/ftrace.c73
1 files changed, 15 insertions, 58 deletions
diff --git a/arch/powerpc/kernel/ftrace.c b/arch/powerpc/kernel/ftrace.c
index e66af6d265e8..44d4d8eb3c85 100644
--- a/arch/powerpc/kernel/ftrace.c
+++ b/arch/powerpc/kernel/ftrace.c
@@ -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 */