From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933988Ab3JOVIa (ORCPT ); Tue, 15 Oct 2013 17:08:30 -0400 Received: from mail-qe0-f49.google.com ([209.85.128.49]:49128 "EHLO mail-qe0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759836Ab3JOVEe (ORCPT ); Tue, 15 Oct 2013 17:04:34 -0400 From: David Long To: linux-arm-kernel@lists.infradead.org Cc: Rabin Vincent , "Jon Medhurst (Tixy)" , Oleg Nesterov , Srikar Dronamraju , Ingo Molnar , linux-kernel@vger.kernel.org Subject: [PATCH v2 02/13] uprobes: allow ignoring of probe hits Date: Tue, 15 Oct 2013 17:04:17 -0400 Message-Id: <1381871068-27660-3-git-send-email-dave.long@linaro.org> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1381871068-27660-1-git-send-email-dave.long@linaro.org> References: <1381871068-27660-1-git-send-email-dave.long@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "David A. Long" 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 v3.12-rc4. Signed-off-by: David A. Long --- 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 9fd60c5..80116c9 100644 --- a/include/linux/uprobes.h +++ b/include/linux/uprobes.h @@ -133,6 +133,7 @@ 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 unsigned long arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr, 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 ad8e1bd..3955172 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1732,9 +1732,6 @@ 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 @@ -1742,16 +1739,26 @@ 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); } -- 1.8.1.2