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Merge tag 'perf-kprobes-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

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Pull perf/kprobes updates from Ingo Molnar:
 "This prepares to unify the kretprobe trampoline handler and make
  kretprobe lockless (those patches are still work in progress)"

* tag 'perf-kprobes-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  kprobes: Fix to check probe enabled before disarm_kprobe_ftrace()
  kprobes: Make local functions static
  kprobes: Free kretprobe_instance with RCU callback
  kprobes: Remove NMI context check
  sparc: kprobes: Use generic kretprobe trampoline handler
  sh: kprobes: Use generic kretprobe trampoline handler
  s390: kprobes: Use generic kretprobe trampoline handler
  powerpc: kprobes: Use generic kretprobe trampoline handler
  parisc: kprobes: Use generic kretprobe trampoline handler
  mips: kprobes: Use generic kretprobe trampoline handler
  ia64: kprobes: Use generic kretprobe trampoline handler
  csky: kprobes: Use generic kretprobe trampoline handler
  arc: kprobes: Use generic kretprobe trampoline handler
  arm64: kprobes: Use generic kretprobe trampoline handler
  arm: kprobes: Use generic kretprobe trampoline handler
  x86/kprobes: Use generic kretprobe trampoline handler
  kprobes: Add generic kretprobe trampoline handler
This commit is contained in:
Linus Torvalds
2020-10-12 14:21:15 -07:00
parent 3bff6112c8 bcb53209be
commit 1c6890707e
14 changed files with 166 additions and 856 deletions
Download Patch File Download Diff File Expand all files Collapse all files

51
arch/sparc/kernel/kprobes.c
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@@ -453,6 +453,7 @@ void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
struct pt_regs *regs)
{
ri->ret_addr = (kprobe_opcode_t *)(regs->u_regs[UREG_RETPC] + 8);
ri->fp = NULL;
/* Replace the return addr with trampoline addr */
regs->u_regs[UREG_RETPC] =
@@ -465,58 +466,12 @@ void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
static int __kprobes 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;
unsigned long orig_ret_address = 0;
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);
orig_ret_address = __kretprobe_trampoline_handler(regs, &kretprobe_trampoline, NULL);
regs->tpc = orig_ret_address;
regs->tnpc = orig_ret_address + 4;
kretprobe_hash_unlock(current, &flags);
hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
hlist_del(&ri->hlist);
kfree(ri);
}
/*
* By returning a non-zero value, we are telling
* kprobe_handler() that we don't want the post_handler