diff options
Diffstat (limited to 'arch/microblaze/kernel/ftrace.c')
| -rw-r--r-- | arch/microblaze/kernel/ftrace.c | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/arch/microblaze/kernel/ftrace.c b/arch/microblaze/kernel/ftrace.c index c1889b101cb..0952a8b52c3 100644 --- a/arch/microblaze/kernel/ftrace.c +++ b/arch/microblaze/kernel/ftrace.c @@ -14,6 +14,64 @@ #include <asm/cacheflush.h> #include <linux/ftrace.h> +#ifdef CONFIG_FUNCTION_GRAPH_TRACER +/* + * Hook the return address and push it in the stack of return addrs + * in current thread info. + */ +void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr) +{ + unsigned long old; + int faulted, err; + struct ftrace_graph_ent trace; + unsigned long return_hooker = (unsigned long) + &return_to_handler; + + if (unlikely(atomic_read(¤t->tracing_graph_pause))) + return; + + /* + * Protect against fault, even if it shouldn't + * happen. This tool is too much intrusive to + * ignore such a protection. + */ + asm volatile(" 1: lwi %0, %2, 0; \ + 2: swi %3, %2, 0; \ + addik %1, r0, 0; \ + 3: \ + .section .fixup, \"ax\"; \ + 4: brid 3b; \ + addik %1, r0, 1; \ + .previous; \ + .section __ex_table,\"a\"; \ + .word 1b,4b; \ + .word 2b,4b; \ + .previous;" \ + : "=&r" (old), "=r" (faulted) + : "r" (parent), "r" (return_hooker) + ); + + if (unlikely(faulted)) { + ftrace_graph_stop(); + WARN_ON(1); + return; + } + + err = ftrace_push_return_trace(old, self_addr, &trace.depth, 0); + if (err == -EBUSY) { + *parent = old; + return; + } + + trace.func = self_addr; + /* Only trace if the calling function expects to */ + if (!ftrace_graph_entry(&trace)) { + current->curr_ret_stack--; + *parent = old; + } +} +#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ + #ifdef CONFIG_DYNAMIC_FTRACE /* save value to addr - it is save to do it in asm */ static int ftrace_modify_code(unsigned long addr, unsigned int value) |