diff options
Diffstat (limited to 'arch/mips/kernel')
| -rw-r--r-- | arch/mips/kernel/Makefile | 3 | ||||
| -rw-r--r-- | arch/mips/kernel/ftrace.c | 112 | ||||
| -rw-r--r-- | arch/mips/kernel/mcount.S | 29 |
3 files changed, 143 insertions, 1 deletions
diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile index 1340ba3..8dda214 100644 --- a/arch/mips/kernel/Makefile +++ b/arch/mips/kernel/Makefile @@ -11,6 +11,7 @@ obj-y += cpu-probe.o branch.o entry.o genex.o irq.o process.o \ time.o topology.o traps.o unaligned.o watch.o ifdef CONFIG_FUNCTION_TRACER +CFLAGS_REMOVE_ftrace.o = -pg CFLAGS_REMOVE_early_printk.o = -pg endif @@ -31,7 +32,7 @@ obj-$(CONFIG_SYNC_R4K) += sync-r4k.o obj-$(CONFIG_STACKTRACE) += stacktrace.o obj-$(CONFIG_MODULES) += mips_ksyms.o module.o -obj-$(CONFIG_FUNCTION_TRACER) += mcount.o +obj-$(CONFIG_FUNCTION_TRACER) += mcount.o ftrace.o obj-$(CONFIG_CPU_LOONGSON2) += r4k_fpu.o r4k_switch.o obj-$(CONFIG_CPU_MIPS32) += r4k_fpu.o r4k_switch.o diff --git a/arch/mips/kernel/ftrace.c b/arch/mips/kernel/ftrace.c new file mode 100644 index 0000000..5459a78 --- /dev/null +++ b/arch/mips/kernel/ftrace.c @@ -0,0 +1,112 @@ +/* + * Code for replacing ftrace calls with jumps. + * + * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com> + * Copyright (C) 2009 DSLab, Lanzhou University, China + * Author: Wu Zhangjin <wuzj@lemote.com> + * + * Thanks goes to Steven Rostedt for writing the original x86 version. + */ + +#include <linux/uaccess.h> +#include <linux/init.h> +#include <linux/ftrace.h> + +#include <asm/cacheflush.h> + +#ifdef CONFIG_DYNAMIC_FTRACE + +#define JAL 0x0c000000 /* jump & link: ip --> ra, jump to target */ +#define ADDR_MASK 0x03ffffff /* op_code|addr : 31...26|25 ....0 */ +#define jump_insn_encode(op_code, addr) \ + ((unsigned int)((op_code) | (((addr) >> 2) & ADDR_MASK))) + +static unsigned int ftrace_nop = 0x00000000; + +static int ftrace_modify_code(unsigned long ip, unsigned int new_code) +{ + *(unsigned int *)ip = new_code; + + flush_icache_range(ip, ip + 8); + + return 0; +} + +static int lui_v1; +static int jal_mcount; + +int ftrace_make_nop(struct module *mod, + struct dyn_ftrace *rec, unsigned long addr) +{ + unsigned int new; + unsigned long ip = rec->ip; + + /* We have compiled module with -mlong-calls, but compiled the kernel + * without it, we need to cope with them respectively. */ + if (ip & 0x40000000) { + /* record it for ftrace_make_call */ + if (lui_v1 == 0) + lui_v1 = *(unsigned int *)ip; + + /* lui v1, hi_16bit_of_mcount --> b 1f (0x10000004) + * addiu v1, v1, low_16bit_of_mcount + * move at, ra + * jalr v1 + * nop + * 1f: (ip + 12) + */ + new = 0x10000004; + } else { + /* record/calculate it for ftrace_make_call */ + if (jal_mcount == 0) { + /* We can record it directly like this: + * jal_mcount = *(unsigned int *)ip; + * Herein, jump over the first two nop instructions */ + jal_mcount = jump_insn_encode(JAL, (MCOUNT_ADDR + 8)); + } + + /* move at, ra + * jalr v1 --> nop + */ + new = ftrace_nop; + } + return ftrace_modify_code(ip, new); +} + +static int modified; /* initialized as 0 by default */ + +int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) +{ + unsigned int new; + unsigned long ip = rec->ip; + + /* We just need to remove the "b ftrace_stub" at the fist time! */ + if (modified == 0) { + modified = 1; + ftrace_modify_code(addr, ftrace_nop); + } + /* ip, module: 0xc0000000, kernel: 0x80000000 */ + new = (ip & 0x40000000) ? lui_v1 : jal_mcount; + + return ftrace_modify_code(ip, new); +} + +#define FTRACE_CALL_IP ((unsigned long)(&ftrace_call)) + +int ftrace_update_ftrace_func(ftrace_func_t func) +{ + unsigned int new; + + new = jump_insn_encode(JAL, (unsigned long)func); + + return ftrace_modify_code(FTRACE_CALL_IP, new); +} + +int __init ftrace_dyn_arch_init(void *data) +{ + /* The return code is retured via data */ + *(unsigned long *)data = 0; + + return 0; +} +#endif /* CONFIG_DYNAMIC_FTRACE */ diff --git a/arch/mips/kernel/mcount.S b/arch/mips/kernel/mcount.S index cbb45ed..ffc4259 100644 --- a/arch/mips/kernel/mcount.S +++ b/arch/mips/kernel/mcount.S @@ -58,6 +58,33 @@ move ra, AT .endm +#ifdef CONFIG_DYNAMIC_FTRACE + +NESTED(ftrace_caller, PT_SIZE, ra) + .globl _mcount +_mcount: + b ftrace_stub + nop + lw t0, function_trace_stop + bnez t0, ftrace_stub + nop + + MCOUNT_SAVE_REGS + + move a0, ra /* arg1: next ip, selfaddr */ + .globl ftrace_call +ftrace_call: + nop /* a placeholder for the call to a real tracing function */ + move a1, AT /* arg2: the caller's next ip, parent */ + + MCOUNT_RESTORE_REGS + .globl ftrace_stub +ftrace_stub: + RETURN_BACK + END(ftrace_caller) + +#else /* ! CONFIG_DYNAMIC_FTRACE */ + NESTED(_mcount, PT_SIZE, ra) lw t0, function_trace_stop bnez t0, ftrace_stub @@ -82,5 +109,7 @@ ftrace_stub: RETURN_BACK END(_mcount) +#endif /* ! CONFIG_DYNAMIC_FTRACE */ + .set at .set reorder |