diff options
Diffstat (limited to 'arch/powerpc/kernel/ftrace.c')
| -rw-r--r-- | arch/powerpc/kernel/ftrace.c | 222 |
1 files changed, 164 insertions, 58 deletions
diff --git a/arch/powerpc/kernel/ftrace.c b/arch/powerpc/kernel/ftrace.c index 60c60ccf5e3c..5b5d16b2cac8 100644 --- a/arch/powerpc/kernel/ftrace.c +++ b/arch/powerpc/kernel/ftrace.c @@ -5,6 +5,9 @@ * * Thanks goes out to P.A. Semi, Inc for supplying me with a PPC64 box. * + * Added function graph tracer code, taken from x86 that was written + * by Frederic Weisbecker, and ported to PPC by Steven Rostedt. + * */ #include <linux/spinlock.h> @@ -20,14 +23,6 @@ #include <asm/code-patching.h> #include <asm/ftrace.h> -#if 0 -#define DEBUGP printk -#else -#define DEBUGP(fmt , ...) do { } while (0) -#endif - -static unsigned int ftrace_nop = PPC_NOP_INSTR; - #ifdef CONFIG_PPC32 # define GET_ADDR(addr) addr #else @@ -35,37 +30,23 @@ static unsigned int ftrace_nop = PPC_NOP_INSTR; # define GET_ADDR(addr) (*(unsigned long *)addr) #endif - -static unsigned int ftrace_calc_offset(long ip, long addr) +#ifdef CONFIG_DYNAMIC_FTRACE +static unsigned int ftrace_nop_replace(void) { - return (int)(addr - ip); + return PPC_INST_NOP; } -static unsigned char *ftrace_nop_replace(void) +static unsigned int +ftrace_call_replace(unsigned long ip, unsigned long addr, int link) { - return (char *)&ftrace_nop; -} - -static unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr) -{ - static unsigned int op; + unsigned int op; - /* - * It would be nice to just use create_function_call, but that will - * update the code itself. Here we need to just return the - * instruction that is going to be modified, without modifying the - * code. - */ addr = GET_ADDR(addr); - /* Set to "bl addr" */ - op = 0x48000001 | (ftrace_calc_offset(ip, addr) & 0x03fffffc); + /* if (link) set op to 'bl' else 'b' */ + op = create_branch((unsigned int *)ip, addr, link ? 1 : 0); - /* - * No locking needed, this must be called via kstop_machine - * which in essence is like running on a uniprocessor machine. - */ - return (unsigned char *)&op; + return op; } #ifdef CONFIG_PPC64 @@ -77,10 +58,9 @@ static unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr) #endif static int -ftrace_modify_code(unsigned long ip, unsigned char *old_code, - unsigned char *new_code) +ftrace_modify_code(unsigned long ip, unsigned int old, unsigned int new) { - unsigned char replaced[MCOUNT_INSN_SIZE]; + unsigned int replaced; /* * Note: Due to modules and __init, code can @@ -93,15 +73,15 @@ ftrace_modify_code(unsigned long ip, unsigned char *old_code, */ /* read the text we want to modify */ - if (probe_kernel_read(replaced, (void *)ip, MCOUNT_INSN_SIZE)) + if (probe_kernel_read(&replaced, (void *)ip, MCOUNT_INSN_SIZE)) return -EFAULT; /* Make sure it is what we expect it to be */ - if (memcmp(replaced, old_code, MCOUNT_INSN_SIZE) != 0) + if (replaced != old) return -EINVAL; /* replace the text with the new text */ - if (probe_kernel_write((void *)ip, new_code, MCOUNT_INSN_SIZE)) + if (probe_kernel_write((void *)ip, &new, MCOUNT_INSN_SIZE)) return -EPERM; flush_icache_range(ip, ip + 8); @@ -119,6 +99,8 @@ static int test_24bit_addr(unsigned long ip, unsigned long addr) return create_branch((unsigned int *)ip, addr, 0); } +#ifdef CONFIG_MODULES + static int is_bl_op(unsigned int op) { return (op & 0xfc000003) == 0x48000001; @@ -175,7 +157,7 @@ __ftrace_make_nop(struct module *mod, * 0xe8, 0x4c, 0x00, 0x28, ld r2,40(r12) */ - DEBUGP("ip:%lx jumps to %lx r2: %lx", ip, tramp, mod->arch.toc); + pr_debug("ip:%lx jumps to %lx r2: %lx", ip, tramp, mod->arch.toc); /* Find where the trampoline jumps to */ if (probe_kernel_read(jmp, (void *)tramp, sizeof(jmp))) { @@ -183,7 +165,7 @@ __ftrace_make_nop(struct module *mod, return -EFAULT; } - DEBUGP(" %08x %08x", jmp[0], jmp[1]); + pr_debug(" %08x %08x", jmp[0], jmp[1]); /* verify that this is what we expect it to be */ if (((jmp[0] & 0xffff0000) != 0x3d820000) || @@ -199,18 +181,18 @@ __ftrace_make_nop(struct module *mod, offset = ((unsigned)((unsigned short)jmp[0]) << 16) + (int)((short)jmp[1]); - DEBUGP(" %x ", offset); + pr_debug(" %x ", offset); /* get the address this jumps too */ tramp = mod->arch.toc + offset + 32; - DEBUGP("toc: %lx", tramp); + pr_debug("toc: %lx", tramp); if (probe_kernel_read(jmp, (void *)tramp, 8)) { printk(KERN_ERR "Failed to read %lx\n", tramp); return -EFAULT; } - DEBUGP(" %08x %08x\n", jmp[0], jmp[1]); + pr_debug(" %08x %08x\n", jmp[0], jmp[1]); ptr = ((unsigned long)jmp[0] << 32) + jmp[1]; @@ -287,7 +269,7 @@ __ftrace_make_nop(struct module *mod, * 0x4e, 0x80, 0x04, 0x20 bctr */ - DEBUGP("ip:%lx jumps to %lx", ip, tramp); + pr_debug("ip:%lx jumps to %lx", ip, tramp); /* Find where the trampoline jumps to */ if (probe_kernel_read(jmp, (void *)tramp, sizeof(jmp))) { @@ -295,7 +277,7 @@ __ftrace_make_nop(struct module *mod, return -EFAULT; } - DEBUGP(" %08x %08x ", jmp[0], jmp[1]); + pr_debug(" %08x %08x ", jmp[0], jmp[1]); /* verify that this is what we expect it to be */ if (((jmp[0] & 0xffff0000) != 0x3d600000) || @@ -311,7 +293,7 @@ __ftrace_make_nop(struct module *mod, if (tramp & 0x8000) tramp -= 0x10000; - DEBUGP(" %x ", tramp); + pr_debug(" %x ", tramp); if (tramp != addr) { printk(KERN_ERR @@ -320,7 +302,7 @@ __ftrace_make_nop(struct module *mod, return -EINVAL; } - op = PPC_NOP_INSTR; + op = PPC_INST_NOP; if (probe_kernel_write((void *)ip, &op, MCOUNT_INSN_SIZE)) return -EPERM; @@ -330,12 +312,13 @@ __ftrace_make_nop(struct module *mod, return 0; } #endif /* PPC64 */ +#endif /* CONFIG_MODULES */ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr) { - unsigned char *old, *new; unsigned long ip = rec->ip; + unsigned int old, new; /* * If the calling address is more that 24 bits away, @@ -344,11 +327,12 @@ int ftrace_make_nop(struct module *mod, */ if (test_24bit_addr(ip, addr)) { /* within range */ - old = ftrace_call_replace(ip, addr); + old = ftrace_call_replace(ip, addr, 1); new = ftrace_nop_replace(); return ftrace_modify_code(ip, old, new); } +#ifdef CONFIG_MODULES /* * Out of range jumps are called from modules. * We should either already have a pointer to the module @@ -373,9 +357,13 @@ int ftrace_make_nop(struct module *mod, mod = rec->arch.mod; return __ftrace_make_nop(mod, rec, addr); - +#else + /* We should not get here without modules */ + return -EINVAL; +#endif /* CONFIG_MODULES */ } +#ifdef CONFIG_MODULES #ifdef CONFIG_PPC64 static int __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) @@ -392,7 +380,7 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) * b +8; ld r2,40(r1) */ if (((op[0] != 0x48000008) || (op[1] != 0xe8410028)) && - ((op[0] != PPC_NOP_INSTR) || (op[1] != PPC_NOP_INSTR))) { + ((op[0] != PPC_INST_NOP) || (op[1] != PPC_INST_NOP))) { printk(KERN_ERR "Expected NOPs but have %x %x\n", op[0], op[1]); return -EINVAL; } @@ -414,7 +402,7 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) /* ld r2,40(r1) */ op[1] = 0xe8410028; - DEBUGP("write to %lx\n", rec->ip); + pr_debug("write to %lx\n", rec->ip); if (probe_kernel_write((void *)ip, op, MCOUNT_INSN_SIZE * 2)) return -EPERM; @@ -435,7 +423,7 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) return -EFAULT; /* It should be pointing to a nop */ - if (op != PPC_NOP_INSTR) { + if (op != PPC_INST_NOP) { printk(KERN_ERR "Expected NOP but have %x\n", op); return -EINVAL; } @@ -454,7 +442,7 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) return -EINVAL; } - DEBUGP("write to %lx\n", rec->ip); + pr_debug("write to %lx\n", rec->ip); if (probe_kernel_write((void *)ip, &op, MCOUNT_INSN_SIZE)) return -EPERM; @@ -464,11 +452,12 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) return 0; } #endif /* CONFIG_PPC64 */ +#endif /* CONFIG_MODULES */ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) { - unsigned char *old, *new; unsigned long ip = rec->ip; + unsigned int old, new; /* * If the calling address is more that 24 bits away, @@ -478,10 +467,11 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) if (test_24bit_addr(ip, addr)) { /* within range */ old = ftrace_nop_replace(); - new = ftrace_call_replace(ip, addr); + new = ftrace_call_replace(ip, addr, 1); return ftrace_modify_code(ip, old, new); } +#ifdef CONFIG_MODULES /* * Out of range jumps are called from modules. * Being that we are converting from nop, it had better @@ -493,16 +483,20 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) } return __ftrace_make_call(rec, addr); +#else + /* We should not get here without modules */ + return -EINVAL; +#endif /* CONFIG_MODULES */ } int ftrace_update_ftrace_func(ftrace_func_t func) { unsigned long ip = (unsigned long)(&ftrace_call); - unsigned char old[MCOUNT_INSN_SIZE], *new; + unsigned int old, new; int ret; - memcpy(old, &ftrace_call, MCOUNT_INSN_SIZE); - new = ftrace_call_replace(ip, (unsigned long)func); + old = *(unsigned int *)&ftrace_call; + new = ftrace_call_replace(ip, (unsigned long)func, 1); ret = ftrace_modify_code(ip, old, new); return ret; @@ -517,3 +511,115 @@ 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); +extern void ftrace_graph_stub(void); + +int ftrace_enable_ftrace_graph_caller(void) +{ + unsigned long ip = (unsigned long)(&ftrace_graph_call); + unsigned long addr = (unsigned long)(&ftrace_graph_caller); + unsigned long stub = (unsigned long)(&ftrace_graph_stub); + unsigned int old, new; + + old = ftrace_call_replace(ip, stub, 0); + new = ftrace_call_replace(ip, addr, 0); + + return ftrace_modify_code(ip, old, new); +} + +int ftrace_disable_ftrace_graph_caller(void) +{ + unsigned long ip = (unsigned long)(&ftrace_graph_call); + unsigned long addr = (unsigned long)(&ftrace_graph_caller); + unsigned long stub = (unsigned long)(&ftrace_graph_stub); + unsigned int old, new; + + old = ftrace_call_replace(ip, addr, 0); + new = ftrace_call_replace(ip, stub, 0); + + return ftrace_modify_code(ip, old, new); +} +#endif /* CONFIG_DYNAMIC_FTRACE */ + +#ifdef CONFIG_PPC64 +extern void mod_return_to_handler(void); +#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 old; + unsigned long long calltime; + int faulted; + struct ftrace_graph_ent trace; + unsigned long return_hooker = (unsigned long)&return_to_handler; + + if (unlikely(atomic_read(¤t->tracing_graph_pause))) + return; + +#if CONFIG_PPC64 + /* non core kernel code needs to save and restore the TOC */ + if (REGION_ID(self_addr) != KERNEL_REGION_ID) + return_hooker = (unsigned long)&mod_return_to_handler; +#endif + + return_hooker = GET_ADDR(return_hooker); + + /* + * Protect against fault, even if it shouldn't + * happen. This tool is too much intrusive to + * ignore such a protection. + */ + asm volatile( + "1: " PPC_LL "%[old], 0(%[parent])\n" + "2: " PPC_STL "%[return_hooker], 0(%[parent])\n" + " li %[faulted], 0\n" + "3:\n" + + ".section .fixup, \"ax\"\n" + "4: li %[faulted], 1\n" + " b 3b\n" + ".previous\n" + + ".section __ex_table,\"a\"\n" + PPC_LONG_ALIGN "\n" + PPC_LONG "1b,4b\n" + PPC_LONG "2b,4b\n" + ".previous" + + : [old] "=r" (old), [faulted] "=r" (faulted) + : [parent] "r" (parent), [return_hooker] "r" (return_hooker) + : "memory" + ); + + if (unlikely(faulted)) { + ftrace_graph_stop(); + WARN_ON(1); + return; + } + + calltime = cpu_clock(raw_smp_processor_id()); + + if (ftrace_push_return_trace(old, calltime, + self_addr, &trace.depth) == -EBUSY) { + *parent = old; + return; + } + + trace.func = self_addr; + + /* Only trace if the calling function expects to */ + if (!ftrace_graph_entry(&trace)) { + current->curr_ret_stack--; + *parent = old; + } +} +#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ |