powerpc: kprobes: Use generic kretprobe trampoline handler

Use the generic kretprobe trampoline handler. Don't use
framepointer verification.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/159870610825.1229682.2090635992093223399.stgit@devnote2

diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index 6ab9b4d..01ab216 100644 (file)
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -218,6 +218,7 @@ bool arch_kprobe_on_func_entry(unsigned long offset)
 void arch_prepare_kretprobe(struct kretprobe_instance *ri, struct pt_regs *regs)
 {
        ri->ret_addr = (kprobe_opcode_t *)regs->link;
+       ri->fp = NULL;
 
        /* Replace the return addr with trampoline addr */
        regs->link = (unsigned long)kretprobe_trampoline;
@@ -396,50 +397,9 @@ asm(".global kretprobe_trampoline\n"
  */
 static int trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
 {
-       struct kretprobe_instance *ri = NULL;
-       struct hlist_head *head, empty_rp;
-       struct hlist_node *tmp;
-       unsigned long flags, orig_ret_address = 0;
-       unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline;
-
-       INIT_HLIST_HEAD(&empty_rp);
-       kretprobe_hash_lock(current, &head, &flags);
-
-       /*
-        * 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 than 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, 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, &empty_rp);
-
-               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;
-       }
-
-       kretprobe_assert(ri, orig_ret_address, trampoline_address);
+       unsigned long orig_ret_address;
 
+       orig_ret_address = __kretprobe_trampoline_handler(regs, &kretprobe_trampoline, NULL);
        /*
         * We get here through one of two paths:
         * 1. by taking a trap -> kprobe_handler() -> here
@@ -458,13 +418,6 @@ static int trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
        regs->nip = orig_ret_address - 4;
        regs->link = orig_ret_address;
 
-       kretprobe_hash_unlock(current, &flags);
-
-       hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
-               hlist_del(&ri->hlist);
-               kfree(ri);
-       }
-
        return 0;
 }
 NOKPROBE_SYMBOL(trampoline_probe_handler);