Received: from mail.onstor.com ([66.201.51.107]) by onstor-exch02.onstor.net with Microsoft SMTPSVC(6.0.3790.3959);
	 Tue, 23 Sep 2008 01:29:07 -0700
Received: from chiesmta2-1.messageone.com ([216.203.30.55]) by mail.onstor.com with Microsoft SMTPSVC(6.0.3790.3959);
	 Tue, 23 Sep 2008 01:29:07 -0700
Received: from ftp.linux-mips.org (ftp.linux-mips.org [213.58.128.207])
	by chiesmta2-1.messageone.com (8.13.8/8.13.8) with ESMTP id m8N8T3if022497
	for <andy.sharp@onstor.com>; Tue, 23 Sep 2008 03:29:06 -0500
Received: from localhost.localdomain ([127.0.0.1]:10446 "EHLO
	ftp.linux-mips.org") by ftp.linux-mips.org with ESMTP
	id S20184464AbYIWHJQ (ORCPT <rfc822;andy.sharp@onstor.com>);
	Tue, 23 Sep 2008 08:09:16 +0100
Received: with ECARTIS (v1.0.0; list linux-mips); Tue, 23 Sep 2008 08:08:59 +0100 (BST)
Received: from smtp1.dnsmadeeasy.com ([205.234.170.134]:45707 "EHLO
	smtp1.dnsmadeeasy.com") by ftp.linux-mips.org with ESMTP
	id S20184457AbYIWHIx (ORCPT <rfc822;linux-mips@linux-mips.org>);
	Tue, 23 Sep 2008 08:08:53 +0100
Received: from smtp1.dnsmadeeasy.com (localhost [127.0.0.1])
	by smtp1.dnsmadeeasy.com (Postfix) with ESMTP id 50433320C8E
	for <linux-mips@linux-mips.org>; Tue, 23 Sep 2008 07:08:50 +0000 (UTC)
X-Authenticated-Name: js.dnsmadeeasy
X-Transit-System: In case of SPAM please contact abuse@dnsmadeeasy.com
Received: from avtrex.com (unknown [173.8.135.205])
	by smtp1.dnsmadeeasy.com (Postfix) with ESMTP
	for <linux-mips@linux-mips.org>; Tue, 23 Sep 2008 07:08:50 +0000 (UTC)
Received: from silver64.hq2.avtrex.com ([192.168.7.229]) by avtrex.com with Microsoft SMTPSVC(6.0.3790.1830);
	 Tue, 23 Sep 2008 00:08:45 -0700
Message-ID: <48D895FD.1070407@avtrex.com>
Date: 	Tue, 23 Sep 2008 00:08:45 -0700
From: David Daney <ddaney@avtrex.com>
User-Agent: Thunderbird 2.0.0.16 (X11/20080723)
MIME-Version: 1.0
To: linux-mips@linux-mips.org
Subject: [Patch 4/6] MIPS: Watch exception handling for HARDWARE_WATCHPOINTS.
References: <48D89470.5090404@avtrex.com>
In-Reply-To: <48D89470.5090404@avtrex.com>
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
X-OriginalArrivalTime: 23 Sep 2008 07:08:45.0742 (UTC) FILETIME=[3814F4E0:01C91D4B]
X-archive-position: 20597
X-ecartis-version: Ecartis v1.0.0
Sender: linux-mips-bounce@linux-mips.org
Errors-to: linux-mips-bounce@linux-mips.org
X-original-sender: ddaney@avtrex.com
Precedence: bulk
X-list: 	linux-mips
X-MessageOne-Virus-Version: vendor=fsecure engine=4.65.7161:2.4.4,1.2.40,4.0.164 definitions=2008-09-23_01:2008-09-19,2008-09-23,2008-09-22 signatures=0
X-MessageOne-Virus-Scanned: Clean
X-MessageOne-Envelope-Sender: linux-mips-bounce@linux-mips.org
X-MessageOne-Spam-Details: rule=m773emszm_notspam policy=m773emszm score=0 spamscore=0 ipscore=0 phishscore=0 bulkscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx engine=3.1.0-0805090000 definitions=main-0809230008
X-MessageOne-Spam-Score: 0
X-MessageOne-Spam-Bar: 
Return-Path: linux-mips-bounce@linux-mips.org


Here we hook up the watch exception handler so that it sends SIGTRAP when
the hardware watch registers are triggered.

Signed-off-by: David Daney <ddaney@avtrex.com>
---
 arch/mips/kernel/genex.S |    4 ++++
 arch/mips/kernel/traps.c |   24 +++++++++++++++++++-----
 2 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/arch/mips/kernel/genex.S b/arch/mips/kernel/genex.S
index c6ada98..15a9bde 100644
--- a/arch/mips/kernel/genex.S
+++ b/arch/mips/kernel/genex.S
@@ -416,7 +416,11 @@ NESTED(nmi_handler, PT_SIZE, sp)
 	BUILD_HANDLER tr tr sti silent			/* #13 */
 	BUILD_HANDLER fpe fpe fpe silent		/* #15 */
 	BUILD_HANDLER mdmx mdmx sti silent		/* #22 */
+#ifdef 	CONFIG_HARDWARE_WATCHPOINTS
+	BUILD_HANDLER watch watch sti silent		/* #23 */
+#else
 	BUILD_HANDLER watch watch sti verbose		/* #23 */
+#endif
 	BUILD_HANDLER mcheck mcheck cli verbose		/* #24 */
 	BUILD_HANDLER mt mt sti silent			/* #25 */
 	BUILD_HANDLER dsp dsp sti silent		/* #26 */
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 6bee290..3b1ef59 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -42,6 +42,7 @@
 #include <asm/tlbdebug.h>
 #include <asm/traps.h>
 #include <asm/uaccess.h>
+#include <asm/watch.h>
 #include <asm/mmu_context.h>
 #include <asm/types.h>
 #include <asm/stacktrace.h>
@@ -907,13 +908,26 @@ asmlinkage void do_mdmx(struct pt_regs *regs)
 
 asmlinkage void do_watch(struct pt_regs *regs)
 {
+	u32 cause;
+
 	/*
-	 * We use the watch exception where available to detect stack
-	 * overflows.
+	 * Clear WP (bit 22) bit of cause register so we don't loop
+	 * forever.
 	 */
-	dump_tlb_all();
-	show_regs(regs);
-	panic("Caught WATCH exception - probably caused by stack overflow.");
+	cause = read_c0_cause();
+	cause &= ~(1 << 22);
+	write_c0_cause(cause);
+
+	/*
+	 * If the current thread has the watch registers loaded, save
+	 * their values and send SIGTRAP.  Otherwise another thread
+	 * left the registers set, clear them and continue.
+	 */
+	if (test_tsk_thread_flag(current, TIF_LOAD_WATCH)) {
+		mips_read_watch_registers();
+		force_sig(SIGTRAP, current);
+	} else
+		mips_clear_watch_registers();
 }
 
 asmlinkage void do_mcheck(struct pt_regs *regs)
-- 
1.5.5.1


