diff options
Diffstat (limited to 'arch/ppc64/kernel/kprobes.c')
| -rw-r--r-- | arch/ppc64/kernel/kprobes.c | 79 |
1 files changed, 61 insertions, 18 deletions
diff --git a/arch/ppc64/kernel/kprobes.c b/arch/ppc64/kernel/kprobes.c index 103daaf7357..782ce3efa2c 100644 --- a/arch/ppc64/kernel/kprobes.c +++ b/arch/ppc64/kernel/kprobes.c @@ -32,40 +32,53 @@ #include <linux/ptrace.h> #include <linux/spinlock.h> #include <linux/preempt.h> +#include <asm/cacheflush.h> #include <asm/kdebug.h> #include <asm/sstep.h> -/* kprobe_status settings */ -#define KPROBE_HIT_ACTIVE 0x00000001 -#define KPROBE_HIT_SS 0x00000002 - static struct kprobe *current_kprobe; static unsigned long kprobe_status, kprobe_saved_msr; +static struct kprobe *kprobe_prev; +static unsigned long kprobe_status_prev, kprobe_saved_msr_prev; static struct pt_regs jprobe_saved_regs; int arch_prepare_kprobe(struct kprobe *p) { + int ret = 0; kprobe_opcode_t insn = *p->addr; - if (IS_MTMSRD(insn) || IS_RFID(insn)) - /* cannot put bp on RFID/MTMSRD */ - return 1; - return 0; + 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"); + ret = -EINVAL; + } + return ret; } void arch_copy_kprobe(struct kprobe *p) { memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t)); + p->opcode = *p->addr; } -void arch_remove_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)); } -static inline void disarm_kprobe(struct kprobe *p, struct pt_regs *regs) +void arch_disarm_kprobe(struct kprobe *p) { *p->addr = p->opcode; - regs->nip = (unsigned long)p->addr; + flush_icache_range((unsigned long) p->addr, + (unsigned long) p->addr + sizeof(kprobe_opcode_t)); +} + +void arch_remove_kprobe(struct kprobe *p) +{ } static inline void prepare_singlestep(struct kprobe *p, struct pt_regs *regs) @@ -78,6 +91,20 @@ static inline void prepare_singlestep(struct kprobe *p, struct pt_regs *regs) regs->nip = (unsigned long)&p->ainsn.insn; } +static inline void save_previous_kprobe(void) +{ + kprobe_prev = current_kprobe; + kprobe_status_prev = kprobe_status; + kprobe_saved_msr_prev = kprobe_saved_msr; +} + +static inline void restore_previous_kprobe(void) +{ + current_kprobe = kprobe_prev; + kprobe_status = kprobe_status_prev; + kprobe_saved_msr = kprobe_saved_msr_prev; +} + static inline int kprobe_handler(struct pt_regs *regs) { struct kprobe *p; @@ -96,8 +123,19 @@ static inline int kprobe_handler(struct pt_regs *regs) unlock_kprobes(); goto no_kprobe; } - disarm_kprobe(p, regs); - ret = 1; + /* We have reentered the kprobe_handler(), since + * another probe was hit while within the handler. + * We here save the original kprobes variables and + * just single step on the instruction of the new probe + * without calling any user handlers. + */ + save_previous_kprobe(); + current_kprobe = p; + kprobe_saved_msr = regs->msr; + p->nmissed++; + prepare_singlestep(p, regs); + kprobe_status = KPROBE_REENTER; + return 1; } else { p = current_kprobe; if (p->break_handler && p->break_handler(p, regs)) { @@ -172,8 +210,6 @@ static void resume_execution(struct kprobe *p, struct pt_regs *regs) ret = emulate_step(regs, p->ainsn.insn[0]); if (ret == 0) regs->nip = (unsigned long)p->addr + 4; - - regs->msr &= ~MSR_SE; } static inline int post_kprobe_handler(struct pt_regs *regs) @@ -181,13 +217,21 @@ static inline int post_kprobe_handler(struct pt_regs *regs) if (!kprobe_running()) return 0; - if (current_kprobe->post_handler) + if ((kprobe_status != KPROBE_REENTER) && current_kprobe->post_handler) { + kprobe_status = KPROBE_HIT_SSDONE; current_kprobe->post_handler(current_kprobe, regs, 0); + } resume_execution(current_kprobe, regs); regs->msr |= kprobe_saved_msr; + /*Restore back the original saved kprobes variables and continue. */ + if (kprobe_status == KPROBE_REENTER) { + restore_previous_kprobe(); + goto out; + } unlock_kprobes(); +out: preempt_enable_no_resched(); /* @@ -210,6 +254,7 @@ static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr) if (kprobe_status & KPROBE_HIT_SS) { resume_execution(current_kprobe, regs); + regs->msr &= ~MSR_SE; regs->msr |= kprobe_saved_msr; unlock_kprobes(); @@ -233,8 +278,6 @@ int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val, */ preempt_disable(); switch (val) { - case DIE_IABR_MATCH: - case DIE_DABR_MATCH: case DIE_BPT: if (kprobe_handler(args->regs)) ret = NOTIFY_STOP; |