diff options
Diffstat (limited to 'arch/powerpc/kernel/ftrace.c')
| -rw-r--r-- | arch/powerpc/kernel/ftrace.c | 79 |
1 files changed, 77 insertions, 2 deletions
diff --git a/arch/powerpc/kernel/ftrace.c b/arch/powerpc/kernel/ftrace.c index 4112175183d..c9b1547f65a 100644 --- a/arch/powerpc/kernel/ftrace.c +++ b/arch/powerpc/kernel/ftrace.c @@ -5,6 +5,9 @@ * * Thanks goes out to P.A. Semi, Inc for supplying me with a PPC64 box. * + * Added function graph tracer code, taken from x86 that was written + * by Frederic Weisbecker, and ported to PPC by Steven Rostedt. + * */ #include <linux/spinlock.h> @@ -20,8 +23,6 @@ #include <asm/code-patching.h> #include <asm/ftrace.h> -static unsigned int ftrace_nop = PPC_NOP_INSTR; - #ifdef CONFIG_PPC32 # define GET_ADDR(addr) addr #else @@ -29,6 +30,8 @@ static unsigned int ftrace_nop = PPC_NOP_INSTR; # define GET_ADDR(addr) (*(unsigned long *)addr) #endif +#ifdef CONFIG_DYNAMIC_FTRACE +static unsigned int ftrace_nop = PPC_NOP_INSTR; static unsigned int ftrace_calc_offset(long ip, long addr) { @@ -525,3 +528,75 @@ int __init ftrace_dyn_arch_init(void *data) return 0; } +#endif /* CONFIG_DYNAMIC_FTRACE */ + +#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; + unsigned long long calltime; + int faulted; + struct ftrace_graph_ent trace; + unsigned long return_hooker = (unsigned long) + &return_to_handler; + + if (unlikely(atomic_read(¤t->tracing_graph_pause))) + return; + + return_hooker = GET_ADDR(return_hooker); + + /* + * 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:" + + ".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; + } + + calltime = cpu_clock(raw_smp_processor_id()); + + if (ftrace_push_return_trace(old, calltime, + self_addr, &trace.depth) == -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 */ |