diff options
| -rw-r--r-- | arch/ppc64/kernel/kprobes.c | 99 | ||||
| -rw-r--r-- | arch/ppc64/kernel/process.c | 4 | ||||
| -rw-r--r-- | include/asm-ppc64/kprobes.h | 3 |
3 files changed, 106 insertions, 0 deletions
diff --git a/arch/ppc64/kernel/kprobes.c b/arch/ppc64/kernel/kprobes.c index 86cc549..1d2ff6d 100644 --- a/arch/ppc64/kernel/kprobes.c +++ b/arch/ppc64/kernel/kprobes.c @@ -122,6 +122,23 @@ static inline void restore_previous_kprobe(void) kprobe_saved_msr = kprobe_saved_msr_prev; } +void arch_prepare_kretprobe(struct kretprobe *rp, 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++; + } +} + static inline int kprobe_handler(struct pt_regs *regs) { struct kprobe *p; @@ -212,6 +229,78 @@ no_kprobe: } /* + * Function return probe trampoline: + * - init_kprobes() establishes a probepoint here + * - When the probed function returns, this probe + * causes the handlers to fire + */ +void kretprobe_trampoline_holder(void) +{ + asm volatile(".global kretprobe_trampoline\n" + "kretprobe_trampoline:\n" + "nop\n"); +} + +/* + * Called when the probe at kretprobe trampoline is hit + */ +int trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) +{ + struct kretprobe_instance *ri = NULL; + struct hlist_head *head; + struct hlist_node *node, *tmp; + unsigned long orig_ret_address = 0; + unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline; + + head = kretprobe_inst_table_head(current); + + /* + * 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 + * return probe was registered for a target function. + * + * We can handle this because: + * - instances are always inserted at the head of the list + * - when multiple return probes are registered for the same + * function, the first instance's ret_addr will point to the + * real return address, and all the rest will point to + * kretprobe_trampoline + */ + hlist_for_each_entry_safe(ri, node, tmp, head, hlist) { + if (ri->task != current) + /* another task is sharing our hash bucket */ + continue; + + if (ri->rp && ri->rp->handler) + ri->rp->handler(ri, regs); + + orig_ret_address = (unsigned long)ri->ret_addr; + recycle_rp_inst(ri); + + if (orig_ret_address != trampoline_address) + /* + * This is the real return address. Any other + * instances associated with this task are for + * other calls deeper on the call stack + */ + break; + } + + BUG_ON(!orig_ret_address || (orig_ret_address == trampoline_address)); + regs->nip = orig_ret_address; + + unlock_kprobes(); + + /* + * By returning a non-zero value, we are telling + * kprobe_handler() that we have handled unlocking + * and re-enabling preemption. + */ + return 1; +} + +/* * Called after single-stepping. p->addr is the address of the * instruction whose first byte has been replaced by the "breakpoint" * instruction. To avoid the SMP problems that can occur when we @@ -349,3 +438,13 @@ int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) memcpy(regs, &jprobe_saved_regs, sizeof(struct pt_regs)); return 1; } + +static struct kprobe trampoline_p = { + .addr = (kprobe_opcode_t *) &kretprobe_trampoline, + .pre_handler = trampoline_probe_handler +}; + +int __init arch_init(void) +{ + return register_kprobe(&trampoline_p); +} diff --git a/arch/ppc64/kernel/process.c b/arch/ppc64/kernel/process.c index aba8955..f7cae05 100644 --- a/arch/ppc64/kernel/process.c +++ b/arch/ppc64/kernel/process.c @@ -36,6 +36,7 @@ #include <linux/kallsyms.h> #include <linux/interrupt.h> #include <linux/utsname.h> +#include <linux/kprobes.h> #include <asm/pgtable.h> #include <asm/uaccess.h> @@ -307,6 +308,8 @@ void show_regs(struct pt_regs * regs) void exit_thread(void) { + kprobe_flush_task(current); + #ifndef CONFIG_SMP if (last_task_used_math == current) last_task_used_math = NULL; @@ -321,6 +324,7 @@ void flush_thread(void) { struct thread_info *t = current_thread_info(); + kprobe_flush_task(current); if (t->flags & _TIF_ABI_PENDING) t->flags ^= (_TIF_ABI_PENDING | _TIF_32BIT); diff --git a/include/asm-ppc64/kprobes.h b/include/asm-ppc64/kprobes.h index 790cf7c..0802919 100644 --- a/include/asm-ppc64/kprobes.h +++ b/include/asm-ppc64/kprobes.h @@ -42,6 +42,9 @@ typedef unsigned int kprobe_opcode_t; #define JPROBE_ENTRY(pentry) (kprobe_opcode_t *)((func_descr_t *)pentry) +#define ARCH_SUPPORTS_KRETPROBES +void kretprobe_trampoline(void); + /* Architecture specific copy of original instruction */ struct arch_specific_insn { /* copy of original instruction */ |
