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author | Jiri Kosina <jkosina@suse.cz> | 2010-08-04 15:14:38 +0200 |
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committer | Jiri Kosina <jkosina@suse.cz> | 2010-08-04 15:14:38 +0200 |
commit | d790d4d583aeaed9fc6f8a9f4d9f8ce6b1c15c7f (patch) | |
tree | 854ab394486288d40fa8179cbfaf66e8bdc44b0f /arch/mips/kernel/ftrace.c | |
parent | 73b2c7165b76b20eb1290e7efebc33cfd21db1ca (diff) | |
parent | 3a09b1be53d23df780a0cd0e4087a05e2ca4a00c (diff) | |
download | op-kernel-dev-d790d4d583aeaed9fc6f8a9f4d9f8ce6b1c15c7f.zip op-kernel-dev-d790d4d583aeaed9fc6f8a9f4d9f8ce6b1c15c7f.tar.gz |
Merge branch 'master' into for-next
Diffstat (limited to 'arch/mips/kernel/ftrace.c')
-rw-r--r-- | arch/mips/kernel/ftrace.c | 184 |
1 files changed, 112 insertions, 72 deletions
diff --git a/arch/mips/kernel/ftrace.c b/arch/mips/kernel/ftrace.c index e9e64e0..5a84a1f 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. @@ -12,18 +12,62 @@ #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> + +/* + * If the Instruction Pointer is in module space (0xc0000000), return true; + * otherwise, it is in kernel space (0x80000000), return false. + * + * FIXME: This will not work when the kernel space and module space are the + * same. If they are the same, we need to modify scripts/recordmcount.pl, + * ftrace_make_nop/call() and the other related parts to ensure the + * enabling/disabling of the calling site to _mcount is right for both kernel + * and module. + */ + +static inline int in_module(unsigned long ip) +{ + return ip & 0x40000000; +} #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; +#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) \ + ((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) { @@ -40,67 +84,56 @@ 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. */ - 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; - } - - /* lui v1, hi_16bit_of_mcount --> b 1f (0x10000004) + /* + * We have compiled module with -mlong-calls, but compiled the kernel + * without it, we need to cope with them respectively. + */ + if (in_module(ip)) { +#if defined(KBUILD_MCOUNT_RA_ADDRESS) && defined(CONFIG_32BIT) + /* + * lui v1, hi_16bit_of_mcount --> b 1f (0x10000005) + * addiu v1, v1, low_16bit_of_mcount + * move at, ra + * move $12, ra_address + * jalr v1 + * sub sp, sp, 8 + * 1: offset = 5 instructions + */ + new = INSN_B_1F_5; +#else + /* + * 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) + * nop | move $12, ra_address | sub sp, sp, 8 + * 1: offset = 4 instructions */ - new = 0x10000004; + 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 = jump_insn_encode(JAL, (MCOUNT_ADDR + 8)); - } - - /* move at, ra - * jalr v1 --> nop + /* + * move at, ra + * jal _mcount --> nop */ - new = ftrace_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, ftrace_nop); - } /* ip, module: 0xc0000000, kernel: 0x80000000 */ - new = (ip & 0x40000000) ? lui_v1 : jal_mcount; + new = in_module(ip) ? insn_lui_v1_hi16_mcount : insn_jal_ftrace_caller; return ftrace_modify_code(ip, new); } @@ -111,44 +144,48 @@ int ftrace_update_ftrace_func(ftrace_func_t func) { unsigned int new; - new = jump_insn_encode(JAL, (unsigned long)func); + new = INSN_JAL((unsigned long)func); return ftrace_modify_code(FTRACE_CALL_IP, new); } 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; return 0; } -#endif /* CONFIG_DYNAMIC_FTRACE */ +#endif /* CONFIG_DYNAMIC_FTRACE */ #ifdef CONFIG_FUNCTION_GRAPH_TRACER #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) { - return ftrace_modify_code(FTRACE_GRAPH_CALL_IP, ftrace_nop); + return ftrace_modify_code(FTRACE_GRAPH_CALL_IP, INSN_NOP); } -#endif /* !CONFIG_DYNAMIC_FTRACE */ +#endif /* CONFIG_DYNAMIC_FTRACE */ #ifndef KBUILD_MCOUNT_RA_ADDRESS + #define S_RA_SP (0xafbf << 16) /* s{d,w} ra, offset(sp) */ #define S_R_SP (0xafb0 << 16) /* s{d,w} R, offset(sp) */ #define OFFSET_MASK 0xffff /* stack offset range: 0 ~ PT_SIZE */ @@ -162,17 +199,17 @@ unsigned long ftrace_get_parent_addr(unsigned long self_addr, unsigned int code; int faulted; - /* in module or kernel? */ - if (self_addr & 0x40000000) { - /* module: move to the instruction "lui v1, HI_16BIT_OF_MCOUNT" */ - ip = self_addr - 20; - } else { - /* kernel: move to the instruction "move ra, at" */ - ip = self_addr - 12; - } + /* + * For module, move the ip from calling site of mcount to the + * instruction "lui v1, hi_16bit_of_mcount"(offset is 20), but for + * kernel, move to the instruction "move ra, at"(offset is 12) + */ + ip = self_addr - (in_module(self_addr) ? 20 : 12); - /* search the text until finding the non-store instruction or "s{d,w} - * ra, offset(sp)" instruction */ + /* + * search the text until finding the non-store instruction or "s{d,w} + * ra, offset(sp)" instruction + */ do { ip -= 4; @@ -181,10 +218,11 @@ unsigned long ftrace_get_parent_addr(unsigned long self_addr, if (unlikely(faulted)) return 0; - - /* If we hit the non-store instruction before finding where the + /* + * If we hit the non-store instruction before finding where the * ra is stored, then this is a leaf function and it does not - * store the ra on the stack. */ + * store the ra on the stack + */ if ((code & S_R_SP) != S_R_SP) return parent_addr; @@ -202,7 +240,7 @@ unsigned long ftrace_get_parent_addr(unsigned long self_addr, return 0; } -#endif +#endif /* !KBUILD_MCOUNT_RA_ADDRESS */ /* * Hook the return address and push it in the stack of return addrs @@ -220,7 +258,8 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, if (unlikely(atomic_read(¤t->tracing_graph_pause))) return; - /* "parent" is the stack address saved the return address of the caller + /* + * "parent" is the stack address saved the return address of the caller * of _mcount. * * if the gcc < 4.5, a leaf function does not save the return address @@ -242,10 +281,11 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, goto out; #ifndef KBUILD_MCOUNT_RA_ADDRESS parent = (unsigned long *)ftrace_get_parent_addr(self_addr, old, - (unsigned long)parent, - fp); - /* If fails when getting the stack address of the non-leaf function's - * ra, stop function graph tracer and return */ + (unsigned long)parent, fp); + /* + * If fails when getting the stack address of the non-leaf function's + * ra, stop function graph tracer and return + */ if (parent == 0) goto out; #endif @@ -272,4 +312,4 @@ out: ftrace_graph_stop(); WARN_ON(1); } -#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ +#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ |