diff options
Diffstat (limited to 'arch/powerpc/kernel/kprobes.c')
| -rw-r--r-- | arch/powerpc/kernel/kprobes.c | 162 |
1 files changed, 99 insertions, 63 deletions
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c index 4657563f881..2f72af82513 100644 --- a/arch/powerpc/kernel/kprobes.c +++ b/arch/powerpc/kernel/kprobes.c @@ -30,14 +30,18 @@ #include <linux/ptrace.h> #include <linux/preempt.h> #include <linux/module.h> +#include <linux/kdebug.h> +#include <linux/slab.h> +#include <asm/code-patching.h> #include <asm/cacheflush.h> -#include <asm/kdebug.h> #include <asm/sstep.h> #include <asm/uaccess.h> DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL; DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); +struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}}; + int __kprobes arch_prepare_kprobe(struct kprobe *p) { int ret = 0; @@ -46,12 +50,13 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p) if ((unsigned long)p->addr & 0x03) { printk("Attempt to register kprobe at an unaligned address\n"); ret = -EINVAL; - } else if (IS_MTMSRD(insn) || IS_RFID(insn)) { - printk("Cannot register a kprobe on rfid or mtmsrd\n"); + } else if (IS_MTMSRD(insn) || IS_RFID(insn) || IS_RFI(insn)) { + printk("Cannot register a kprobe on rfi/rfid or mtmsr[d]\n"); ret = -EINVAL; } - /* insn must be on a special executable page on ppc64 */ + /* insn must be on a special executable page on ppc64. This is + * not explicitly required on ppc32 (right now), but it doesn't hurt */ if (!ret) { p->ainsn.insn = get_insn_slot(); if (!p->ainsn.insn) @@ -59,12 +64,14 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p) } if (!ret) { - memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t)); + memcpy(p->ainsn.insn, p->addr, + MAX_INSN_SIZE * sizeof(kprobe_opcode_t)); p->opcode = *p->addr; flush_icache_range((unsigned long)p->ainsn.insn, (unsigned long)p->ainsn.insn + sizeof(kprobe_opcode_t)); } + p->ainsn.boostable = 0; return ret; } @@ -84,14 +91,15 @@ void __kprobes arch_disarm_kprobe(struct kprobe *p) void __kprobes arch_remove_kprobe(struct kprobe *p) { - mutex_lock(&kprobe_mutex); - free_insn_slot(p->ainsn.insn, 0); - mutex_unlock(&kprobe_mutex); + if (p->ainsn.insn) { + free_insn_slot(p->ainsn.insn, 0); + p->ainsn.insn = NULL; + } } static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs) { - regs->msr |= MSR_SE; + enable_single_step(regs); /* * On powerpc we should single step on the original @@ -123,23 +131,13 @@ static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs, kcb->kprobe_saved_msr = regs->msr; } -/* Called with kretprobe_lock held */ -void __kprobes arch_prepare_kretprobe(struct kretprobe *rp, +void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri, struct pt_regs *regs) { - struct kretprobe_instance *ri; - - if ((ri = get_free_rp_inst(rp)) != NULL) { - ri->rp = rp; - ri->task = current; - ri->ret_addr = (kprobe_opcode_t *)regs->link; - - /* Replace the return addr with trampoline addr */ - regs->link = (unsigned long)kretprobe_trampoline; - add_rp_inst(ri); - } else { - rp->nmissed++; - } + ri->ret_addr = (kprobe_opcode_t *)regs->link; + + /* Replace the return addr with trampoline addr */ + regs->link = (unsigned long)kretprobe_trampoline; } static int __kprobes kprobe_handler(struct pt_regs *regs) @@ -163,7 +161,8 @@ static int __kprobes kprobe_handler(struct pt_regs *regs) kprobe_opcode_t insn = *p->ainsn.insn; if (kcb->kprobe_status == KPROBE_HIT_SS && is_trap(insn)) { - regs->msr &= ~MSR_SE; + /* Turn off 'trace' bits */ + regs->msr &= ~MSR_SINGLESTEP; regs->msr |= kcb->kprobe_saved_msr; goto no_kprobe; } @@ -232,6 +231,38 @@ static int __kprobes kprobe_handler(struct pt_regs *regs) return 1; ss_probe: + if (p->ainsn.boostable >= 0) { + 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; + + if (p->post_handler) + p->post_handler(p, regs, 0); + + kcb->kprobe_status = KPROBE_HIT_SSDONE; + 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; return 1; @@ -247,7 +278,7 @@ no_kprobe: * - When the probed function returns, this probe * causes the handlers to fire */ -void kretprobe_trampoline_holder(void) +static void __used kretprobe_trampoline_holder(void) { asm volatile(".global kretprobe_trampoline\n" "kretprobe_trampoline:\n" @@ -257,22 +288,22 @@ void kretprobe_trampoline_holder(void) /* * Called when the probe at kretprobe trampoline is hit */ -int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) +static int __kprobes trampoline_probe_handler(struct kprobe *p, + struct pt_regs *regs) { struct kretprobe_instance *ri = NULL; struct hlist_head *head, empty_rp; - struct hlist_node *node, *tmp; + struct hlist_node *tmp; unsigned long flags, orig_ret_address = 0; unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline; INIT_HLIST_HEAD(&empty_rp); - spin_lock_irqsave(&kretprobe_lock, flags); - head = kretprobe_inst_table_head(current); + kretprobe_hash_lock(current, &head, &flags); /* * It is possible to have multiple instances associated with a given * task either because an multiple functions in the call path - * have a return probe installed on them, and/or more then one return + * have a return probe installed on them, and/or more than one return * return probe was registered for a target function. * * We can handle this because: @@ -282,7 +313,7 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) * real return address, and all the rest will point to * kretprobe_trampoline */ - hlist_for_each_entry_safe(ri, node, tmp, head, hlist) { + hlist_for_each_entry_safe(ri, tmp, head, hlist) { if (ri->task != current) /* another task is sharing our hash bucket */ continue; @@ -302,14 +333,14 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) break; } - BUG_ON(!orig_ret_address || (orig_ret_address == trampoline_address)); + kretprobe_assert(ri, orig_ret_address, trampoline_address); regs->nip = orig_ret_address; reset_current_kprobe(); - spin_unlock_irqrestore(&kretprobe_lock, flags); + kretprobe_hash_unlock(current, &flags); preempt_enable_no_resched(); - hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) { + hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) { hlist_del(&ri->hlist); kfree(ri); } @@ -329,17 +360,6 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) * single-stepped a copy of the instruction. The address of this * copy is p->ainsn.insn. */ -static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs) -{ - int ret; - unsigned int insn = *p->ainsn.insn; - - regs->nip = (unsigned long)p->addr; - ret = emulate_step(regs, insn); - if (ret == 0) - regs->nip = (unsigned long)p->addr + 4; -} - static int __kprobes post_kprobe_handler(struct pt_regs *regs) { struct kprobe *cur = kprobe_running(); @@ -348,12 +368,17 @@ static int __kprobes post_kprobe_handler(struct pt_regs *regs) if (!cur) return 0; + /* make sure we got here for instruction we have a kprobe on */ + if (((unsigned long)cur->ainsn.insn + 4) != regs->nip) + return 0; + if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) { kcb->kprobe_status = KPROBE_HIT_SSDONE; cur->post_handler(cur, regs, 0); } - resume_execution(cur, regs); + /* Adjust nip to after the single-stepped instruction */ + regs->nip = (unsigned long)cur->addr + 4; regs->msr |= kcb->kprobe_saved_msr; /*Restore back the original saved kprobes variables and continue. */ @@ -367,16 +392,16 @@ out: /* * if somebody else is singlestepping across a probe point, msr - * will have SE set, in which case, continue the remaining processing + * will have DE/SE set, in which case, continue the remaining processing * of do_debug, as if this is not a probe hit. */ - if (regs->msr & MSR_SE) + if (regs->msr & MSR_SINGLESTEP) return 0; return 1; } -static int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr) +int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr) { struct kprobe *cur = kprobe_running(); struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); @@ -393,7 +418,7 @@ static int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr) * normal page fault. */ regs->nip = (unsigned long)cur->addr; - regs->msr &= ~MSR_SE; + regs->msr &= ~MSR_SINGLESTEP; /* Turn off 'trace' bits */ regs->msr |= kcb->kprobe_saved_msr; if (kcb->kprobe_status == KPROBE_REENTER) restore_previous_kprobe(kcb); @@ -405,7 +430,7 @@ static int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr) case KPROBE_HIT_SSDONE: /* * We increment the nmissed count for accounting, - * we can also use npre/npostfault count for accouting + * we can also use npre/npostfault count for accounting * these specific fault cases. */ kprobes_inc_nmissed_count(cur); @@ -461,20 +486,17 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self, if (post_kprobe_handler(args->regs)) ret = NOTIFY_STOP; break; - case DIE_PAGE_FAULT: - /* kprobe_running() needs smp_processor_id() */ - preempt_disable(); - if (kprobe_running() && - kprobe_fault_handler(args->regs, args->trapnr)) - ret = NOTIFY_STOP; - preempt_enable(); - break; default: break; } return ret; } +unsigned long arch_deref_entry_point(void *entry) +{ + return ppc_global_function_entry(entry); +} + int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) { struct jprobe *jp = container_of(p, struct jprobe, kp); @@ -483,18 +505,24 @@ int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) memcpy(&kcb->jprobe_saved_regs, regs, sizeof(struct pt_regs)); /* setup return addr to the jprobe handler routine */ - regs->nip = (unsigned long)(((func_descr_t *)jp->entry)->entry); + regs->nip = arch_deref_entry_point(jp->entry); +#ifdef CONFIG_PPC64 +#if defined(_CALL_ELF) && _CALL_ELF == 2 + regs->gpr[12] = (unsigned long)jp->entry; +#else regs->gpr[2] = (unsigned long)(((func_descr_t *)jp->entry)->toc); +#endif +#endif return 1; } -void __kprobes jprobe_return(void) +void __used __kprobes jprobe_return(void) { asm volatile("trap" ::: "memory"); } -void __kprobes jprobe_return_end(void) +static void __used __kprobes jprobe_return_end(void) { }; @@ -521,3 +549,11 @@ int __init arch_init_kprobes(void) { return register_kprobe(&trampoline_p); } + +int __kprobes arch_trampoline_kprobe(struct kprobe *p) +{ + if (p->addr == (kprobe_opcode_t *)&kretprobe_trampoline) + return 1; + + return 0; +} |