diff options
Diffstat (limited to 'arch/blackfin/kernel/ftrace.c')
-rw-r--r-- | arch/blackfin/kernel/ftrace.c | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/arch/blackfin/kernel/ftrace.c b/arch/blackfin/kernel/ftrace.c new file mode 100644 index 000000000..095de0fa0 --- /dev/null +++ b/arch/blackfin/kernel/ftrace.c @@ -0,0 +1,125 @@ +/* + * ftrace graph code + * + * Copyright (C) 2009-2010 Analog Devices Inc. + * Licensed under the GPL-2 or later. + */ + +#include <linux/ftrace.h> +#include <linux/kernel.h> +#include <linux/sched.h> +#include <linux/uaccess.h> +#include <linux/atomic.h> +#include <asm/cacheflush.h> + +#ifdef CONFIG_DYNAMIC_FTRACE + +static const unsigned char mnop[] = { + 0x03, 0xc0, 0x00, 0x18, /* MNOP; */ + 0x03, 0xc0, 0x00, 0x18, /* MNOP; */ +}; + +static void bfin_make_pcrel24(unsigned char *insn, unsigned long src, + unsigned long dst) +{ + uint32_t pcrel = (dst - src) >> 1; + insn[0] = pcrel >> 16; + insn[1] = 0xe3; + insn[2] = pcrel; + insn[3] = pcrel >> 8; +} +#define bfin_make_pcrel24(insn, src, dst) bfin_make_pcrel24(insn, src, (unsigned long)(dst)) + +static int ftrace_modify_code(unsigned long ip, const unsigned char *code, + unsigned long len) +{ + int ret = probe_kernel_write((void *)ip, (void *)code, len); + flush_icache_range(ip, ip + len); + return ret; +} + +int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, + unsigned long addr) +{ + /* Turn the mcount call site into two MNOPs as those are 32bit insns */ + return ftrace_modify_code(rec->ip, mnop, sizeof(mnop)); +} + +int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) +{ + /* Restore the mcount call site */ + unsigned char call[8]; + call[0] = 0x67; /* [--SP] = RETS; */ + call[1] = 0x01; + bfin_make_pcrel24(&call[2], rec->ip + 2, addr); + call[6] = 0x27; /* RETS = [SP++]; */ + call[7] = 0x01; + return ftrace_modify_code(rec->ip, call, sizeof(call)); +} + +int ftrace_update_ftrace_func(ftrace_func_t func) +{ + unsigned char call[4]; + unsigned long ip = (unsigned long)&ftrace_call; + bfin_make_pcrel24(call, ip, func); + return ftrace_modify_code(ip, call, sizeof(call)); +} + +int __init ftrace_dyn_arch_init(void) +{ + return 0; +} + +#endif + +#ifdef CONFIG_FUNCTION_GRAPH_TRACER + +# ifdef CONFIG_DYNAMIC_FTRACE + +extern void ftrace_graph_call(void); + +int ftrace_enable_ftrace_graph_caller(void) +{ + unsigned long ip = (unsigned long)&ftrace_graph_call; + uint16_t jump_pcrel12 = ((unsigned long)&ftrace_graph_caller - ip) >> 1; + jump_pcrel12 |= 0x2000; + return ftrace_modify_code(ip, (void *)&jump_pcrel12, sizeof(jump_pcrel12)); +} + +int ftrace_disable_ftrace_graph_caller(void) +{ + return ftrace_modify_code((unsigned long)&ftrace_graph_call, empty_zero_page, 2); +} + +# endif + +/* + * 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 frame_pointer) +{ + struct ftrace_graph_ent trace; + unsigned long return_hooker = (unsigned long)&return_to_handler; + + if (unlikely(atomic_read(¤t->tracing_graph_pause))) + return; + + if (ftrace_push_return_trace(*parent, self_addr, &trace.depth, + frame_pointer) == -EBUSY) + return; + + trace.func = self_addr; + + /* Only trace if the calling function expects to */ + if (!ftrace_graph_entry(&trace)) { + current->curr_ret_stack--; + return; + } + + /* all is well in the world ! hijack RETS ... */ + *parent = return_hooker; +} + +#endif |