s390/kprobes: enable kretprobes framepointer verification

Use regs->gprs[15] for framepointer verification. This enables
additional sanity checks for nested kretprobes.

Reviewed-by: Tobias Huschle <huschle@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c
index e32c14fd128218f94220e6438146c32a6d14dac8..0032bdbe8e3fa1d7a7b2440a1ee096bb590b3dc4 100644 (file)
--- 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);
 
@@ -385,7 +385,7 @@ NOKPROBE_SYMBOL(arch_kretprobe_fixup_return);
  */
 void trampoline_probe_handler(struct pt_regs *regs)
 {
-       kretprobe_trampoline_handler(regs, NULL);
+       kretprobe_trampoline_handler(regs, (void *)regs->gprs[15]);
 }
 NOKPROBE_SYMBOL(trampoline_probe_handler);