diff options
Diffstat (limited to 'arch/mips/kernel/ftrace.c')
| -rw-r--r-- | arch/mips/kernel/ftrace.c | 93 |
1 files changed, 49 insertions, 44 deletions
diff --git a/arch/mips/kernel/ftrace.c b/arch/mips/kernel/ftrace.c index b1b8fec2432f..c4042cad836e 100644 --- a/arch/mips/kernel/ftrace.c +++ b/arch/mips/kernel/ftrace.c @@ -2,7 +2,7 @@ * Code for replacing ftrace calls with jumps. * * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com> - * Copyright (C) 2009 DSLab, Lanzhou University, China + * Copyright (C) 2009, 2010 DSLab, Lanzhou University, China * Author: Wu Zhangjin <wuzhangjin@gmail.com> * * Thanks goes to Steven Rostedt for writing the original x86 version. @@ -12,21 +12,46 @@ #include <linux/init.h> #include <linux/ftrace.h> -#include <asm/cacheflush.h> #include <asm/asm.h> #include <asm/asm-offsets.h> +#include <asm/cacheflush.h> +#include <asm/uasm.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))) #define INSN_B_1F_4 0x10000004 /* b 1f; offset = 4 */ #define INSN_B_1F_5 0x10000005 /* b 1f; offset = 5 */ #define INSN_NOP 0x00000000 /* nop */ -#define INSN_JAL(addr) jump_insn_encode(JAL, addr) +#define INSN_JAL(addr) \ + ((unsigned int)(JAL | (((addr) >> 2) & ADDR_MASK))) + +static unsigned int insn_jal_ftrace_caller __read_mostly; +static unsigned int insn_lui_v1_hi16_mcount __read_mostly; +static unsigned int insn_j_ftrace_graph_caller __maybe_unused __read_mostly; + +static inline void ftrace_dyn_arch_init_insns(void) +{ + u32 *buf; + unsigned int v1; + + /* lui v1, hi16_mcount */ + v1 = 3; + buf = (u32 *)&insn_lui_v1_hi16_mcount; + UASM_i_LA_mostly(&buf, v1, MCOUNT_ADDR); + + /* jal (ftrace_caller + 8), jump over the first two instruction */ + buf = (u32 *)&insn_jal_ftrace_caller; + uasm_i_jal(&buf, (FTRACE_ADDR + 8)); + +#ifdef CONFIG_FUNCTION_GRAPH_TRACER + /* j ftrace_graph_caller */ + buf = (u32 *)&insn_j_ftrace_graph_caller; + uasm_i_j(&buf, (unsigned long)ftrace_graph_caller); +#endif +} static int ftrace_modify_code(unsigned long ip, unsigned int new_code) { @@ -43,30 +68,20 @@ static int ftrace_modify_code(unsigned long ip, unsigned int new_code) 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; - int faulted; 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. */ + /* + * 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; */ - safe_load_code(lui_v1, ip, faulted); - - if (unlikely(faulted)) - return -EFAULT; - } - #if defined(KBUILD_MCOUNT_RA_ADDRESS) && defined(CONFIG_32BIT) - /* lui v1, hi_16bit_of_mcount --> b 1f (0x10000005) + /* + * lui v1, hi_16bit_of_mcount --> b 1f (0x10000005) * addiu v1, v1, low_16bit_of_mcount * move at, ra * move $12, ra_address @@ -76,7 +91,8 @@ int ftrace_make_nop(struct module *mod, */ new = INSN_B_1F_5; #else - /* lui v1, hi_16bit_of_mcount --> b 1f (0x10000004) + /* + * lui v1, hi_16bit_of_mcount --> b 1f (0x10000004) * addiu v1, v1, low_16bit_of_mcount * move at, ra * jalr v1 @@ -86,36 +102,22 @@ int ftrace_make_nop(struct module *mod, new = INSN_B_1F_4; #endif } 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 = INSN_JAL(MCOUNT_ADDR + 8); - } - - /* move at, ra - * jalr v1 --> nop + /* + * move at, ra + * jal _mcount --> nop */ new = INSN_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, INSN_NOP); - } /* ip, module: 0xc0000000, kernel: 0x80000000 */ - new = (ip & 0x40000000) ? lui_v1 : jal_mcount; + new = (ip & 0x40000000) ? insn_lui_v1_hi16_mcount : insn_jal_ftrace_caller; return ftrace_modify_code(ip, new); } @@ -133,6 +135,12 @@ int ftrace_update_ftrace_func(ftrace_func_t func) int __init ftrace_dyn_arch_init(void *data) { + /* Encode the instructions when booting */ + ftrace_dyn_arch_init_insns(); + + /* Remove "b ftrace_stub" to ensure ftrace_caller() is executed */ + ftrace_modify_code(MCOUNT_ADDR, INSN_NOP); + /* The return code is retured via data */ *(unsigned long *)data = 0; @@ -145,15 +153,12 @@ int __init ftrace_dyn_arch_init(void *data) #ifdef CONFIG_DYNAMIC_FTRACE extern void ftrace_graph_call(void); -#define JMP 0x08000000 /* jump to target directly */ -#define CALL_FTRACE_GRAPH_CALLER \ - jump_insn_encode(JMP, (unsigned long)(&ftrace_graph_caller)) #define FTRACE_GRAPH_CALL_IP ((unsigned long)(&ftrace_graph_call)) int ftrace_enable_ftrace_graph_caller(void) { return ftrace_modify_code(FTRACE_GRAPH_CALL_IP, - CALL_FTRACE_GRAPH_CALLER); + insn_j_ftrace_graph_caller); } int ftrace_disable_ftrace_graph_caller(void) |