Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936474Ab3DRTEm (ORCPT ); Thu, 18 Apr 2013 15:04:42 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57682 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751324Ab3DRTEl (ORCPT ); Thu, 18 Apr 2013 15:04:41 -0400 Date: Thu, 18 Apr 2013 21:01:48 +0200 From: Oleg Nesterov To: Andrew Morton Cc: Alan Stern , Frederic Weisbecker , Ingo Molnar , Jan Kratochvil , Prasad , linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/6] ptrace/x86: introduce ptrace_register_breakpoint() Message-ID: <20130418190148.GA4685@redhat.com> References: <20130418184350.GA4407@redhat.com> <20130418184417.GA4439@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130418184417.GA4439@redhat.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2693 Lines: 103 On 04/18, Oleg Nesterov wrote: > > No functional changes, preparation. > > Extract the "register breakpoint" code from ptrace_get_debugreg() > into the new/generic helper, ptrace_register_breakpoint(). It will > have more users. > > The patch also adds another simple helper, ptrace_fill_bp_fields(), > to factor out the arch_bp_generic_fields() logic in register/modify. This patch is hardly readable. To simplify the review, I attached the new/modified code below. Oleg. static int ptrace_fill_bp_fields(struct perf_event_attr *attr, int len, int type, bool disabled) { int err, bp_len, bp_type; err = arch_bp_generic_fields(len, type, &bp_len, &bp_type); if (!err) { attr->bp_len = bp_len; attr->bp_type = bp_type; attr->disabled = disabled; } return err; } static struct perf_event * ptrace_register_breakpoint(struct task_struct *tsk, int len, int type, unsigned long addr, bool disabled) { struct perf_event_attr attr; int err; ptrace_breakpoint_init(&attr); attr.bp_addr = addr; err = ptrace_fill_bp_fields(&attr, len, type, disabled); if (err) return ERR_PTR(err); return register_user_hw_breakpoint(&attr, ptrace_triggered, NULL, tsk); } static int ptrace_modify_breakpoint(struct perf_event *bp, int len, int type, int disabled) { struct perf_event_attr attr = bp->attr; int err; err = ptrace_fill_bp_fields(&attr, len, type, disabled); if (err) return err; return modify_user_hw_breakpoint(bp, &attr); } static int ptrace_set_breakpoint_addr(struct task_struct *tsk, int nr, unsigned long addr) { struct thread_struct *t = &tsk->thread; struct perf_event *bp = t->ptrace_bps[nr]; int err = 0; if (!bp) { /* * Put stub len and type to create an inactive but correct bp. * * CHECKME: the previous code returned -EIO if the addr wasn't * a valid task virtual addr. The new one will return -EINVAL in * this case. * -EINVAL may be what we want for in-kernel breakpoints users, * but -EIO looks better for ptrace, since we refuse a register * writing for the user. And anyway this is the previous * behaviour. */ bp = ptrace_register_breakpoint(tsk, X86_BREAKPOINT_LEN_1, X86_BREAKPOINT_WRITE, addr, true); if (IS_ERR(bp)) err = PTR_ERR(bp); else t->ptrace_bps[nr] = bp; } else { struct perf_event_attr attr = bp->attr; attr.bp_addr = addr; err = modify_user_hw_breakpoint(bp, &attr); } return err; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/