From: Rabin Vincent rabin@rab.in

Allow arches to decided to ignore a probe hit. ARM will use this to only call handlers if the conditions to execute a conditionally executed instruction are satisfied.

Upleveled for v3.10-rc7.

Signed-off-by: David A. Long dave.long@linaro.org --- include/linux/uprobes.h | 1 + kernel/events/uprobes.c | 17 ++++++++++++----- 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h index fd8bcb9..eca5bd5 100644 --- a/include/linux/uprobes.h +++ b/include/linux/uprobes.h @@ -133,6 +133,7 @@ extern int arch_uprobe_post_xol(struct arch_uprobe *aup, struct pt_regs *regs); extern bool arch_uprobe_xol_was_trapped(struct task_struct *tsk); extern int arch_uprobe_exception_notify(struct notifier_block *self, unsigned long val, void *data); extern void arch_uprobe_abort_xol(struct arch_uprobe *aup, struct pt_regs *regs); +extern bool __weak arch_uprobe_ignore(struct arch_uprobe *aup, struct pt_regs *regs); #else /* !CONFIG_UPROBES */ struct uprobes_state { }; diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index f356974..2f3a4cb 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1734,9 +1734,6 @@ static void handle_swbp(struct pt_regs *regs) return; }

- /* change it in advance for ->handler() and restart */ - instruction_pointer_set(regs, bp_vaddr); - /* * TODO: move copy_insn/etc into _register and remove this hack. * After we hit the bp, _unregister + _register can install the @@ -1744,16 +1741,26 @@ static void handle_swbp(struct pt_regs *regs) */ smp_rmb(); /* pairs with wmb() in install_breakpoint() */ if (unlikely(!test_bit(UPROBE_COPY_INSN, &uprobe->flags))) - goto out; + goto restart;

handler_chain(uprobe, regs); + + if (arch_uprobe_ignore(&uprobe->arch, regs)) + goto out; + if (can_skip_sstep(uprobe, regs)) goto out;

if (!pre_ssout(uprobe, regs, bp_vaddr)) return;

- /* can_skip_sstep() succeeded, or restart if can't singlestep */ +restart: + /* + * cannot singlestep; cannot skip instruction; + * re-execute the instruction. + */ + instruction_pointer_set(regs, bp_vaddr); + out: put_uprobe(uprobe); }