1 files changed, 17 insertions, 32 deletions

diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c
index e27a7d3b0364..0032bdbe8e3f 100644
--- a/arch/s390/kernel/kprobes.c
+++ b/arch/s390/kernel/kprobes.c
@@ -284,11 +284,11 @@ NOKPROBE_SYMBOL(pop_kprobe);
 
 void arch_prepare_kretprobe(struct kretprobe_instance *ri, struct pt_regs *regs)
 {
-	ri->ret_addr = (kprobe_opcode_t *) regs->gprs[14];
-	ri->fp = NULL;
+	ri->ret_addr = (kprobe_opcode_t *)regs->gprs[14];
+	ri->fp = (void *)regs->gprs[15];
 
 	/* Replace the return addr with trampoline addr */
-	regs->gprs[14] = (unsigned long) &__kretprobe_trampoline;
+	regs->gprs[14] = (unsigned long)&__kretprobe_trampoline;
 }
 NOKPROBE_SYMBOL(arch_prepare_kretprobe);
 
@@ -372,33 +372,26 @@ static int kprobe_handler(struct pt_regs *regs)
 }
 NOKPROBE_SYMBOL(kprobe_handler);
 
-/*
- * Function return probe trampoline:
- *	- init_kprobes() establishes a probepoint here
- *	- When the probed function returns, this probe
- *		causes the handlers to fire
- */
-static void __used kretprobe_trampoline_holder(void)
+void arch_kretprobe_fixup_return(struct pt_regs *regs,
+				 kprobe_opcode_t *correct_ret_addr)
 {
-	asm volatile(".global __kretprobe_trampoline\n"
-		     "__kretprobe_trampoline: bcr 0,0\n");
+	/* Replace fake return address with real one. */
+	regs->gprs[14] = (unsigned long)correct_ret_addr;
 }
+NOKPROBE_SYMBOL(arch_kretprobe_fixup_return);
 
 /*
- * Called when the probe at kretprobe trampoline is hit
+ * Called from __kretprobe_trampoline
  */
-static int trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
+void trampoline_probe_handler(struct pt_regs *regs)
 {
-	regs->psw.addr = __kretprobe_trampoline_handler(regs, NULL);
-	/*
-	 * By returning a non-zero value, we are telling
-	 * kprobe_handler() that we don't want the post_handler
-	 * to run (and have re-enabled preemption)
-	 */
-	return 1;
+	kretprobe_trampoline_handler(regs, (void *)regs->gprs[15]);
 }
 NOKPROBE_SYMBOL(trampoline_probe_handler);
 
+/* assembler function that handles the kretprobes must not be probed itself */
+NOKPROBE_SYMBOL(__kretprobe_trampoline);
+
 /*
  * Called after single-stepping.  p->addr is the address of the
  * instruction whose first byte has been replaced by the "breakpoint"
@@ -465,7 +458,6 @@ static int kprobe_trap_handler(struct pt_regs *regs, int trapnr)
 {
 	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
 	struct kprobe *p = kprobe_running();
-	const struct exception_table_entry *entry;
 
 	switch(kcb->kprobe_status) {
 	case KPROBE_HIT_SS:
@@ -487,10 +479,8 @@ static int kprobe_trap_handler(struct pt_regs *regs, int trapnr)
 		 * In case the user-specified fault handler returned
 		 * zero, try to fix up.
 		 */
-		entry = s390_search_extables(regs->psw.addr);
-		if (entry && ex_handle(entry, regs))
+		if (fixup_exception(regs))
 			return 1;
-
 		/*
 		 * fixup_exception() could not handle it,
 		 * Let do_page_fault() fix it.
@@ -554,18 +544,13 @@ int kprobe_exceptions_notify(struct notifier_block *self,
 }
 NOKPROBE_SYMBOL(kprobe_exceptions_notify);
 
-static struct kprobe trampoline = {
-	.addr = (kprobe_opcode_t *) &__kretprobe_trampoline,
-	.pre_handler = trampoline_probe_handler
-};
-
 int __init arch_init_kprobes(void)
 {
-	return register_kprobe(&trampoline);
+	return 0;
 }
 
 int arch_trampoline_kprobe(struct kprobe *p)
 {
-	return p->addr == (kprobe_opcode_t *) &__kretprobe_trampoline;
+	return 0;
 }
 NOKPROBE_SYMBOL(arch_trampoline_kprobe);