From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 9967 invoked by alias); 7 Mar 2006 13:40:40 -0000 Received: (qmail 9925 invoked by uid 22791); 7 Mar 2006 13:40:39 -0000 X-Spam-Status: No, hits=-0.9 required=5.0 tests=AWL,BAYES_00,DNS_FROM_RFC_ABUSE,SPF_SOFTFAIL X-Spam-Check-By: sourceware.org Received: from e6.ny.us.ibm.com (HELO e6.ny.us.ibm.com) (32.97.182.146) by sourceware.org (qpsmtpd/0.31) with ESMTP; Tue, 07 Mar 2006 13:40:37 +0000 Received: from d01relay02.pok.ibm.com (d01relay02.pok.ibm.com [9.56.227.234]) by e6.ny.us.ibm.com (8.12.11/8.12.11) with ESMTP id k27DeZ5i015844 for ; Tue, 7 Mar 2006 08:40:35 -0500 Received: from d01av02.pok.ibm.com (d01av02.pok.ibm.com [9.56.224.216]) by d01relay02.pok.ibm.com (8.12.10/NCO/VER6.8) with ESMTP id k27DeZTQ125196 for ; Tue, 7 Mar 2006 08:40:35 -0500 Received: from d01av02.pok.ibm.com (loopback [127.0.0.1]) by d01av02.pok.ibm.com (8.12.11/8.13.3) with ESMTP id k27DeZ8p029400 for ; Tue, 7 Mar 2006 08:40:35 -0500 Received: from newton.in.ibm.com ([9.124.35.47]) by d01av02.pok.ibm.com (8.12.11/8.12.11) with ESMTP id k27DeYh9029340 for ; Tue, 7 Mar 2006 08:40:35 -0500 Received: by newton.in.ibm.com (Postfix, from userid 500) id B03A8CE3; Tue, 7 Mar 2006 19:12:08 +0530 (IST) Date: Tue, 07 Mar 2006 13:40:00 -0000 From: Prasanna S Panchamukhi To: systemtap@sources.redhat.com Subject: Re: [4/5 PATCH] Kprobes fix for broken fault handling for ia64 Message-ID: <20060307134208.GC32071@in.ibm.com> Reply-To: prasanna@in.ibm.com References: <20060307133832.GA2245@in.ibm.com> <20060307134010.GA32071@in.ibm.com> <20060307134119.GB32071@in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060307134119.GB32071@in.ibm.com> User-Agent: Mutt/1.4.1i X-IsSubscribed: yes Mailing-List: contact systemtap-help@sourceware.org; run by ezmlm Precedence: bulk List-Subscribe: List-Post: List-Help: , Sender: systemtap-owner@sourceware.org X-SW-Source: 2006-q1/txt/msg00726.txt.bz2 This patch fixes the broken kprobes fault handling similar to i386 architecture. Signed-off-by: Prasanna S Panchamukhi Acked-by: Anil S Keshavamurthy arch/ia64/kernel/kprobes.c | 55 ++++++++++++++++++++++++++++++++++++++++----- 1 files changed, 50 insertions(+), 5 deletions(-) diff -puN arch/ia64/kernel/kprobes.c~kprobes-ia64-pagefault-handling arch/ia64/kernel/kprobes.c --- linux-2.6.16-rc5-mm2/arch/ia64/kernel/kprobes.c~kprobes-ia64-pagefault-handling 2006-03-07 11:18:46.000000000 +0530 +++ linux-2.6.16-rc5-mm2-prasanna/arch/ia64/kernel/kprobes.c 2006-03-07 11:21:12.000000000 +0530 @@ -34,6 +34,7 @@ #include #include #include +#include extern void jprobe_inst_return(void); @@ -722,13 +723,57 @@ static int __kprobes kprobes_fault_handl struct kprobe *cur = kprobe_running(); struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); - if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr)) - return 1; - if (kcb->kprobe_status & KPROBE_HIT_SS) { - resume_execution(cur, regs); - reset_current_kprobe(); + switch(kcb->kprobe_status) { + case KPROBE_HIT_SS: + case KPROBE_REENTER: + /* + * We are here because the instruction being single + * stepped caused a page fault. We reset the current + * kprobe and the instruction pointer points back to + * the probe address and allow the page fault handler + * to continue as a normal page fault. + */ + regs->cr_iip = ((unsigned long)cur->addr) & ~0xFULL; + ia64_psr(regs) = ((unsigned long)cur->addr) & 0xf; + if (kcb->kprobe_status == KPROBE_REENTER) + restore_previous_kprobe(kcb); + else + reset_current_kprobe(); preempt_enable_no_resched(); + break; + case KPROBE_HIT_ACTIVE: + case KPROBE_HIT_SSDONE: + /* + * We increment the nmissed count for accounting, + * we can also use npre/npostfault count for accouting + * these specific fault cases. + */ + kprobes_inc_nmissed_count(cur); + + /* + * We come here because instructions in the pre/post + * handler caused the page_fault, this could happen + * if handler tries to access user space by + * copy_from_user(), get_user() etc. Let the + * user-specified handler try to fix it first. + */ + if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr)) + return 1; + + /* + * In case the user-specified fault handler returned + * zero, try to fix up. + */ + if (ia64_done_with_exception(regs)) + return 1; + /* + * ia64_done_with_exception() could not handle it, + * Let ia64_do_page_fault() fix it. + */ + break; + default: + break; } return 0; _ -- Prasanna S Panchamukhi Linux Technology Center India Software Labs, IBM Bangalore Email: prasanna@in.ibm.com Ph: 91-80-51776329