The following commit has been merged into the perf/kprobes branch of tip:
Commit-ID: 94509582d1d173c4777b8832ecbac6dff2ccbfa7
Gitweb: https://git.kernel.org/tip/94509582d1d173c4777b8832ecbac6dff2ccbfa7
Author: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
AuthorDate: Sat, 29 Aug 2020 22:00:24 +09:00
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Tue, 08 Sep 2020 11:52:32 +02:00
arm: kprobes: Use generic kretprobe trampoline handler
Use the generic kretprobe trampoline handler. Use regs->ARM_fp
for framepointer verification.
Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Link: https://lore.kernel.org/r/159870602406.1229682.10496730247473708592.stgit@devnote2
---
arch/arm/probes/kprobes/core.c | 78 +--------------------------------
1 file changed, 3 insertions(+), 75 deletions(-)
diff --git a/arch/arm/probes/kprobes/core.c b/arch/arm/probes/kprobes/core.c
index feefa20..a965311 100644
--- a/arch/arm/probes/kprobes/core.c
+++ b/arch/arm/probes/kprobes/core.c
@@ -413,87 +413,15 @@ void __naked __kprobes kretprobe_trampoline(void)
/* Called from kretprobe_trampoline */
static __used __kprobes void *trampoline_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
- * a return probe installed on them, and/or more than one 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;
-
- 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 *)regs->ARM_fp);
}
void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
struct pt_regs *regs)
{
ri->ret_addr = (kprobe_opcode_t *)regs->ARM_lr;
+ ri->fp = (void *)regs->ARM_fp;
/* Replace the return addr with trampoline addr. */
regs->ARM_lr = (unsigned long)&kretprobe_trampoline;
|