The following commit has been merged into the perf/kprobes branch of tip:
Commit-ID: 95a4b7a24f55efd4fbc77c020fe0aab3e1f37f8a
Gitweb: https://git.kernel.org/tip/95a4b7a24f55efd4fbc77c020fe0aab3e1f37f8a
Author: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
AuthorDate: Sat, 29 Aug 2020 22:00:35 +09:00
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Tue, 08 Sep 2020 11:52:32 +02:00
arm64: kprobes: Use generic kretprobe trampoline handler
Use the generic kretprobe trampoline handler, and use
kernel_stack_pointer(regs) for framepointer verification.
Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Link: https://lore.kernel.org/r/159870603544.1229682.10309733593594205725.stgit@devnote2
---
arch/arm64/kernel/probes/kprobes.c | 78 +----------------------------
1 file changed, 3 insertions(+), 75 deletions(-)
diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c
index 5290f17..deba738 100644
--- a/arch/arm64/kernel/probes/kprobes.c
+++ b/arch/arm64/kernel/probes/kprobes.c
@@ -464,87 +464,15 @@ int __init arch_populate_kprobe_blacklist(void)
void __kprobes __used *trampoline_probe_handler(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;
- kprobe_opcode_t *correct_ret_addr = NULL;
-
- 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 multiple functions in the call path have
- * return probes installed on them, and/or more than one
- * return probe was registered for a target function.
- *
- * We can handle this because:
- * - instances are always pushed into the head of the list
- * - when multiple return probes are registered for the same
- * function, the (chronologically) first instance's ret_addr
- * will be 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;
-
- orig_ret_address = (unsigned long)ri->ret_addr;
-
- 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);
-
- correct_ret_addr = ri->ret_addr;
- hlist_for_each_entry_safe(ri, tmp, head, hlist) {
- if (ri->task != current)
- /* another task is sharing our hash bucket */
- continue;
-
- orig_ret_address = (unsigned long)ri->ret_addr;
- if (ri->rp && ri->rp->handler) {
- __this_cpu_write(current_kprobe, &ri->rp->kp);
- get_kprobe_ctlblk()->kprobe_status = KPROBE_HIT_ACTIVE;
- ri->ret_addr = correct_ret_addr;
- ri->rp->handler(ri, regs);
- __this_cpu_write(current_kprobe, NULL);
- }
-
- 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_hash_unlock(current, &flags);
-
- hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
- hlist_del(&ri->hlist);
- kfree(ri);
- }
- return (void *)orig_ret_address;
+ return (void *)kretprobe_trampoline_handler(regs, &kretprobe_trampoline,
+ (void *)kernel_stack_pointer(regs));
}
void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
struct pt_regs *regs)
{
ri->ret_addr = (kprobe_opcode_t *)regs->regs[30];
+ ri->fp = (void *)kernel_stack_pointer(regs);
/* replace return addr (x30) with trampoline */
regs->regs[30] = (long)&kretprobe_trampoline;
|