Commit d04c02f8 authored by Naveen N. Rao's avatar Naveen N. Rao Committed by Michael Ellerman

powerpc/kprobes: Fix handling of instruction emulation on probe re-entry

Commit 22d8b3de ("powerpc/kprobes: Emulate instructions on kprobe
handler re-entry") enabled emulating instructions on kprobe re-entry,
rather than single-stepping always. However, we didn't update the single
stepping code to only be run if the emulation fails. Also, we missed
re-enabling preemption if the instruction emulation was successful. Fix
those issues.

Fixes: 22d8b3de ("powerpc/kprobes: Emulate instructions on kprobe handler re-entry")
Signed-off-by: default avatarNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent bbb075dd
...@@ -305,16 +305,17 @@ int kprobe_handler(struct pt_regs *regs) ...@@ -305,16 +305,17 @@ int kprobe_handler(struct pt_regs *regs)
save_previous_kprobe(kcb); save_previous_kprobe(kcb);
set_current_kprobe(p, regs, kcb); set_current_kprobe(p, regs, kcb);
kprobes_inc_nmissed_count(p); kprobes_inc_nmissed_count(p);
prepare_singlestep(p, regs);
kcb->kprobe_status = KPROBE_REENTER; kcb->kprobe_status = KPROBE_REENTER;
if (p->ainsn.boostable >= 0) { if (p->ainsn.boostable >= 0) {
ret = try_to_emulate(p, regs); ret = try_to_emulate(p, regs);
if (ret > 0) { if (ret > 0) {
restore_previous_kprobe(kcb); restore_previous_kprobe(kcb);
preempt_enable_no_resched();
return 1; return 1;
} }
} }
prepare_singlestep(p, regs);
return 1; return 1;
} else { } else {
if (*addr != BREAKPOINT_INSTRUCTION) { if (*addr != BREAKPOINT_INSTRUCTION) {
......
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