diff options
Diffstat (limited to 'arch/powerpc/kernel/kprobes.c')
| -rw-r--r-- | arch/powerpc/kernel/kprobes.c | 214 |
1 files changed, 170 insertions, 44 deletions
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c index fce05a38851c..160ae0fa7d0d 100644 --- a/arch/powerpc/kernel/kprobes.c +++ b/arch/powerpc/kernel/kprobes.c @@ -35,6 +35,7 @@ #include <asm/code-patching.h> #include <asm/cacheflush.h> #include <asm/sstep.h> +#include <asm/sections.h> #include <linux/uaccess.h> DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL; @@ -42,7 +43,86 @@ DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}}; -int __kprobes arch_prepare_kprobe(struct kprobe *p) +bool arch_within_kprobe_blacklist(unsigned long addr) +{ + return (addr >= (unsigned long)__kprobes_text_start && + addr < (unsigned long)__kprobes_text_end) || + (addr >= (unsigned long)_stext && + addr < (unsigned long)__head_end); +} + +kprobe_opcode_t *kprobe_lookup_name(const char *name, unsigned int offset) +{ + kprobe_opcode_t *addr; + +#ifdef PPC64_ELF_ABI_v2 + /* PPC64 ABIv2 needs local entry point */ + addr = (kprobe_opcode_t *)kallsyms_lookup_name(name); + if (addr && !offset) { +#ifdef CONFIG_KPROBES_ON_FTRACE + unsigned long faddr; + /* + * Per livepatch.h, ftrace location is always within the first + * 16 bytes of a function on powerpc with -mprofile-kernel. + */ + faddr = ftrace_location_range((unsigned long)addr, + (unsigned long)addr + 16); + if (faddr) + addr = (kprobe_opcode_t *)faddr; + else +#endif + addr = (kprobe_opcode_t *)ppc_function_entry(addr); + } +#elif defined(PPC64_ELF_ABI_v1) + /* + * 64bit powerpc ABIv1 uses function descriptors: + * - Check for the dot variant of the symbol first. + * - If that fails, try looking up the symbol provided. + * + * This ensures we always get to the actual symbol and not + * the descriptor. + * + * Also handle <module:symbol> format. + */ + char dot_name[MODULE_NAME_LEN + 1 + KSYM_NAME_LEN]; + const char *modsym; + bool dot_appended = false; + if ((modsym = strchr(name, ':')) != NULL) { + modsym++; + if (*modsym != '\0' && *modsym != '.') { + /* Convert to <module:.symbol> */ + strncpy(dot_name, name, modsym - name); + dot_name[modsym - name] = '.'; + dot_name[modsym - name + 1] = '\0'; + strncat(dot_name, modsym, + sizeof(dot_name) - (modsym - name) - 2); + dot_appended = true; + } else { + dot_name[0] = '\0'; + strncat(dot_name, name, sizeof(dot_name) - 1); + } + } else if (name[0] != '.') { + dot_name[0] = '.'; + dot_name[1] = '\0'; + strncat(dot_name, name, KSYM_NAME_LEN - 2); + dot_appended = true; + } else { + dot_name[0] = '\0'; + strncat(dot_name, name, KSYM_NAME_LEN - 1); + } + addr = (kprobe_opcode_t *)kallsyms_lookup_name(dot_name); + if (!addr && dot_appended) { + /* Let's try the original non-dot symbol lookup */ + addr = (kprobe_opcode_t *)kallsyms_lookup_name(name); + } +#else + addr = (kprobe_opcode_t *)kallsyms_lookup_name(name); +#endif + + return addr; +} + +int arch_prepare_kprobe(struct kprobe *p) { int ret = 0; kprobe_opcode_t insn = *p->addr; @@ -74,30 +154,34 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p) p->ainsn.boostable = 0; return ret; } +NOKPROBE_SYMBOL(arch_prepare_kprobe); -void __kprobes arch_arm_kprobe(struct kprobe *p) +void arch_arm_kprobe(struct kprobe *p) { *p->addr = BREAKPOINT_INSTRUCTION; flush_icache_range((unsigned long) p->addr, (unsigned long) p->addr + sizeof(kprobe_opcode_t)); } +NOKPROBE_SYMBOL(arch_arm_kprobe); -void __kprobes arch_disarm_kprobe(struct kprobe *p) +void arch_disarm_kprobe(struct kprobe *p) { *p->addr = p->opcode; flush_icache_range((unsigned long) p->addr, (unsigned long) p->addr + sizeof(kprobe_opcode_t)); } +NOKPROBE_SYMBOL(arch_disarm_kprobe); -void __kprobes arch_remove_kprobe(struct kprobe *p) +void arch_remove_kprobe(struct kprobe *p) { if (p->ainsn.insn) { free_insn_slot(p->ainsn.insn, 0); p->ainsn.insn = NULL; } } +NOKPROBE_SYMBOL(arch_remove_kprobe); -static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs) +static nokprobe_inline void prepare_singlestep(struct kprobe *p, struct pt_regs *regs) { enable_single_step(regs); @@ -110,37 +194,80 @@ static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs) regs->nip = (unsigned long)p->ainsn.insn; } -static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb) +static nokprobe_inline void save_previous_kprobe(struct kprobe_ctlblk *kcb) { kcb->prev_kprobe.kp = kprobe_running(); kcb->prev_kprobe.status = kcb->kprobe_status; kcb->prev_kprobe.saved_msr = kcb->kprobe_saved_msr; } -static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb) +static nokprobe_inline void restore_previous_kprobe(struct kprobe_ctlblk *kcb) { __this_cpu_write(current_kprobe, kcb->prev_kprobe.kp); kcb->kprobe_status = kcb->prev_kprobe.status; kcb->kprobe_saved_msr = kcb->prev_kprobe.saved_msr; } -static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs, +static nokprobe_inline void set_current_kprobe(struct kprobe *p, struct pt_regs *regs, struct kprobe_ctlblk *kcb) { __this_cpu_write(current_kprobe, p); kcb->kprobe_saved_msr = regs->msr; } -void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri, - struct pt_regs *regs) +bool arch_function_offset_within_entry(unsigned long offset) +{ +#ifdef PPC64_ELF_ABI_v2 +#ifdef CONFIG_KPROBES_ON_FTRACE + return offset <= 16; +#else + return offset <= 8; +#endif +#else + return !offset; +#endif +} + +void arch_prepare_kretprobe(struct kretprobe_instance *ri, struct pt_regs *regs) { ri->ret_addr = (kprobe_opcode_t *)regs->link; /* Replace the return addr with trampoline addr */ regs->link = (unsigned long)kretprobe_trampoline; } +NOKPROBE_SYMBOL(arch_prepare_kretprobe); -int __kprobes kprobe_handler(struct pt_regs *regs) +int try_to_emulate(struct kprobe *p, struct pt_regs *regs) +{ + int ret; + unsigned int insn = *p->ainsn.insn; + + /* regs->nip is also adjusted if emulate_step returns 1 */ + ret = emulate_step(regs, insn); + if (ret > 0) { + /* + * Once this instruction has been boosted + * successfully, set the boostable flag + */ + if (unlikely(p->ainsn.boostable == 0)) + p->ainsn.boostable = 1; + } else if (ret < 0) { + /* + * We don't allow kprobes on mtmsr(d)/rfi(d), etc. + * So, we should never get here... but, its still + * good to catch them, just in case... + */ + printk("Can't step on instruction %x\n", insn); + BUG(); + } else if (ret == 0) + /* This instruction can't be boosted */ + p->ainsn.boostable = -1; + + return ret; +} +NOKPROBE_SYMBOL(try_to_emulate); + +int kprobe_handler(struct pt_regs *regs) { struct kprobe *p; int ret = 0; @@ -177,10 +304,17 @@ int __kprobes kprobe_handler(struct pt_regs *regs) */ save_previous_kprobe(kcb); set_current_kprobe(p, regs, kcb); - kcb->kprobe_saved_msr = regs->msr; kprobes_inc_nmissed_count(p); prepare_singlestep(p, regs); kcb->kprobe_status = KPROBE_REENTER; + if (p->ainsn.boostable >= 0) { + ret = try_to_emulate(p, regs); + + if (ret > 0) { + restore_previous_kprobe(kcb); + return 1; + } + } return 1; } else { if (*addr != BREAKPOINT_INSTRUCTION) { @@ -197,7 +331,9 @@ int __kprobes kprobe_handler(struct pt_regs *regs) } p = __this_cpu_read(current_kprobe); if (p->break_handler && p->break_handler(p, regs)) { - goto ss_probe; + if (!skip_singlestep(p, regs, kcb)) + goto ss_probe; + ret = 1; } } goto no_kprobe; @@ -235,18 +371,9 @@ int __kprobes kprobe_handler(struct pt_regs *regs) ss_probe: if (p->ainsn.boostable >= 0) { - unsigned int insn = *p->ainsn.insn; + ret = try_to_emulate(p, regs); - /* regs->nip is also adjusted if emulate_step returns 1 */ - ret = emulate_step(regs, insn); if (ret > 0) { - /* - * Once this instruction has been boosted - * successfully, set the boostable flag - */ - if (unlikely(p->ainsn.boostable == 0)) - p->ainsn.boostable = 1; - if (p->post_handler) p->post_handler(p, regs, 0); @@ -254,17 +381,7 @@ ss_probe: reset_current_kprobe(); preempt_enable_no_resched(); return 1; - } else if (ret < 0) { - /* - * We don't allow kprobes on mtmsr(d)/rfi(d), etc. - * So, we should never get here... but, its still - * good to catch them, just in case... - */ - printk("Can't step on instruction %x\n", insn); - BUG(); - } else if (ret == 0) - /* This instruction can't be boosted */ - p->ainsn.boostable = -1; + } } prepare_singlestep(p, regs); kcb->kprobe_status = KPROBE_HIT_SS; @@ -274,6 +391,7 @@ no_kprobe: preempt_enable_no_resched(); return ret; } +NOKPROBE_SYMBOL(kprobe_handler); /* * Function return probe trampoline: @@ -291,8 +409,7 @@ asm(".global kretprobe_trampoline\n" /* * Called when the probe at kretprobe trampoline is hit */ -static int __kprobes trampoline_probe_handler(struct kprobe *p, - struct pt_regs *regs) +static int trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) { struct kretprobe_instance *ri = NULL; struct hlist_head *head, empty_rp; @@ -361,6 +478,7 @@ static int __kprobes trampoline_probe_handler(struct kprobe *p, */ return 1; } +NOKPROBE_SYMBOL(trampoline_probe_handler); /* * Called after single-stepping. p->addr is the address of the @@ -370,7 +488,7 @@ static int __kprobes trampoline_probe_handler(struct kprobe *p, * single-stepped a copy of the instruction. The address of this * copy is p->ainsn.insn. */ -int __kprobes kprobe_post_handler(struct pt_regs *regs) +int kprobe_post_handler(struct pt_regs *regs) { struct kprobe *cur = kprobe_running(); struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); @@ -410,8 +528,9 @@ out: return 1; } +NOKPROBE_SYMBOL(kprobe_post_handler); -int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr) +int kprobe_fault_handler(struct pt_regs *regs, int trapnr) { struct kprobe *cur = kprobe_running(); struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); @@ -474,13 +593,15 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr) } return 0; } +NOKPROBE_SYMBOL(kprobe_fault_handler); unsigned long arch_deref_entry_point(void *entry) { return ppc_global_function_entry(entry); } +NOKPROBE_SYMBOL(arch_deref_entry_point); -int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) +int setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) { struct jprobe *jp = container_of(p, struct jprobe, kp); struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); @@ -497,17 +618,20 @@ int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) return 1; } +NOKPROBE_SYMBOL(setjmp_pre_handler); -void __used __kprobes jprobe_return(void) +void __used jprobe_return(void) { asm volatile("trap" ::: "memory"); } +NOKPROBE_SYMBOL(jprobe_return); -static void __used __kprobes jprobe_return_end(void) +static void __used jprobe_return_end(void) { -}; +} +NOKPROBE_SYMBOL(jprobe_return_end); -int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) +int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) { struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); @@ -520,6 +644,7 @@ int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) preempt_enable_no_resched(); return 1; } +NOKPROBE_SYMBOL(longjmp_break_handler); static struct kprobe trampoline_p = { .addr = (kprobe_opcode_t *) &kretprobe_trampoline, @@ -531,10 +656,11 @@ int __init arch_init_kprobes(void) return register_kprobe(&trampoline_p); } -int __kprobes arch_trampoline_kprobe(struct kprobe *p) +int arch_trampoline_kprobe(struct kprobe *p) { if (p->addr == (kprobe_opcode_t *)&kretprobe_trampoline) return 1; return 0; } +NOKPROBE_SYMBOL(arch_trampoline_kprobe); |