1 files changed, 51 insertions, 26 deletions

diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index dd2886f97e9..0c96611f02f 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -30,8 +30,8 @@
 #include <linux/ptrace.h>
 #include <linux/preempt.h>
 #include <linux/module.h>
+#include <linux/kdebug.h>
 #include <asm/cacheflush.h>
-#include <asm/kdebug.h>
 #include <asm/sstep.h>
 #include <asm/uaccess.h>
 
@@ -59,12 +59,14 @@ 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;
 }
 
@@ -124,22 +126,13 @@ static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
 }
 
 /* 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)
@@ -232,6 +225,38 @@ 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;
@@ -302,7 +327,7 @@ 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();
@@ -376,7 +401,7 @@ out:
 	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();
@@ -461,14 +486,6 @@ 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;
 	}
@@ -525,3 +542,11 @@ 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;
+}