diff options
Diffstat (limited to 'arch/sh/kernel/ftrace.c')
| -rw-r--r-- | arch/sh/kernel/ftrace.c | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/arch/sh/kernel/ftrace.c b/arch/sh/kernel/ftrace.c index 4f62eced0aec..6647dfcb781d 100644 --- a/arch/sh/kernel/ftrace.c +++ b/arch/sh/kernel/ftrace.c @@ -16,11 +16,13 @@ #include <linux/string.h> #include <linux/init.h> #include <linux/io.h> +#include <linux/kernel.h> #include <asm/ftrace.h> #include <asm/cacheflush.h> #include <asm/unistd.h> #include <trace/syscall.h> +#ifdef CONFIG_DYNAMIC_FTRACE static unsigned char ftrace_replaced_code[MCOUNT_INSN_SIZE]; static unsigned char ftrace_nop[4]; @@ -133,6 +135,126 @@ int __init ftrace_dyn_arch_init(void *data) return 0; } +#endif /* CONFIG_DYNAMIC_FTRACE */ + +#ifdef CONFIG_FUNCTION_GRAPH_TRACER +#ifdef CONFIG_DYNAMIC_FTRACE +extern void ftrace_graph_call(void); + +static int ftrace_mod(unsigned long ip, unsigned long old_addr, + unsigned long new_addr) +{ + unsigned char code[MCOUNT_INSN_SIZE]; + + if (probe_kernel_read(code, (void *)ip, MCOUNT_INSN_SIZE)) + return -EFAULT; + + if (old_addr != __raw_readl((unsigned long *)code)) + return -EINVAL; + + __raw_writel(new_addr, ip); + return 0; +} + +int ftrace_enable_ftrace_graph_caller(void) +{ + unsigned long ip, old_addr, new_addr; + + ip = (unsigned long)(&ftrace_graph_call) + GRAPH_INSN_OFFSET; + old_addr = (unsigned long)(&skip_trace); + new_addr = (unsigned long)(&ftrace_graph_caller); + + return ftrace_mod(ip, old_addr, new_addr); +} + +int ftrace_disable_ftrace_graph_caller(void) +{ + unsigned long ip, old_addr, new_addr; + + ip = (unsigned long)(&ftrace_graph_call) + GRAPH_INSN_OFFSET; + old_addr = (unsigned long)(&ftrace_graph_caller); + new_addr = (unsigned long)(&skip_trace); + + return ftrace_mod(ip, old_addr, new_addr); +} +#endif /* CONFIG_DYNAMIC_FTRACE */ + +/* + * Hook the return address and push it in the stack of return addrs + * in the current thread info. + * + * This is the main routine for the function graph tracer. The function + * graph tracer essentially works like this: + * + * parent is the stack address containing self_addr's return address. + * We pull the real return address out of parent and store it in + * current's ret_stack. Then, we replace the return address on the stack + * with the address of return_to_handler. self_addr is the function that + * called mcount. + * + * When self_addr returns, it will jump to return_to_handler which calls + * ftrace_return_to_handler. ftrace_return_to_handler will pull the real + * return address off of current's ret_stack and jump to it. + */ +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: \n\t" + "mov.l @%2, %0 \n\t" + "2: \n\t" + "mov.l %3, @%2 \n\t" + "mov #0, %1 \n\t" + "3: \n\t" + ".section .fixup, \"ax\" \n\t" + "4: \n\t" + "mov.l 5f, %0 \n\t" + "jmp @%0 \n\t" + " mov #1, %1 \n\t" + ".balign 4 \n\t" + "5: .long 3b \n\t" + ".previous \n\t" + ".section __ex_table,\"a\" \n\t" + ".long 1b, 4b \n\t" + ".long 2b, 4b \n\t" + ".previous \n\t" + : "=&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) { + __raw_writel(old, parent); + return; + } + + trace.func = self_addr; + + /* Only trace if the calling function expects to */ + if (!ftrace_graph_entry(&trace)) { + current->curr_ret_stack--; + __raw_writel(old, parent); + } +} +#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ #ifdef CONFIG_FTRACE_SYSCALLS |
