From patchwork Tue Mar 23 14:07:02 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "K.Prasad" X-Patchwork-Id: 48339 X-Patchwork-Delegate: benh@kernel.crashing.org Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from bilbo.ozlabs.org (localhost [127.0.0.1]) by ozlabs.org (Postfix) with ESMTP id D8992B82ED for ; Wed, 24 Mar 2010 01:07:16 +1100 (EST) Received: by ozlabs.org (Postfix) id B3A57B7D15; Wed, 24 Mar 2010 01:07:08 +1100 (EST) Delivered-To: linuxppc-dev@ozlabs.org Received: from e23smtp04.au.ibm.com (e23smtp04.au.ibm.com [202.81.31.146]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e23smtp04.au.ibm.com", Issuer "Equifax" (verified OK)) by ozlabs.org (Postfix) with ESMTPS id AA2CFB7D11 for ; Wed, 24 Mar 2010 01:07:08 +1100 (EST) Received: from d23relay03.au.ibm.com (d23relay03.au.ibm.com [202.81.31.245]) by e23smtp04.au.ibm.com (8.14.3/8.13.1) with ESMTP id o2NE3M6b008412 for ; Wed, 24 Mar 2010 01:03:22 +1100 Received: from d23av03.au.ibm.com (d23av03.au.ibm.com [9.190.234.97]) by d23relay03.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id o2NE784W1835156 for ; Wed, 24 Mar 2010 01:07:08 +1100 Received: from d23av03.au.ibm.com (loopback [127.0.0.1]) by d23av03.au.ibm.com (8.14.3/8.13.1/NCO v10.0 AVout) with ESMTP id o2NE77h8013689 for ; Wed, 24 Mar 2010 01:07:08 +1100 Received: from in.ibm.com (K50wks273965wss.in.ibm.com [9.124.35.127]) by d23av03.au.ibm.com (8.14.3/8.13.1/NCO v10.0 AVin) with ESMTP id o2NE73oX013641 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO); Wed, 24 Mar 2010 01:07:05 +1100 Date: Tue, 23 Mar 2010 19:37:02 +0530 From: "K.Prasad" To: linuxppc-dev@ozlabs.org Subject: [RFC Patch 1/2] PPC64-HWBKPT: Disable interrupts for data breakpoint exceptions Message-ID: <20100323140702.GB21836@in.ibm.com> References: <20100323140008.954823303@pr> MIME-Version: 1.0 Content-Disposition: inline; filename=disable_int_01 User-Agent: Mutt/1.5.19 (2009-01-05) Cc: Michael Neuling , Benjamin Herrenschmidt , shaggy@linux.vnet.ibm.com, Frederic Weisbecker , David Gibson , paulus@samba.org, Alan Stern , "K.Prasad" , Roland McGrath X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.13 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Data address breakpoint exceptions are currently handled along with page-faults which require interrupts to remain in enabled state. Since exception handling for data breakpoints aren't pre-empt safe, we handle them separately. Signed-off-by: K.Prasad --- arch/powerpc/kernel/exceptions-64s.S | 12 ++++++++++++ arch/powerpc/mm/fault.c | 2 +- 2 files changed, 13 insertions(+), 1 deletion(-) Index: linux-2.6.ppc64_test/arch/powerpc/kernel/exceptions-64s.S =================================================================== --- linux-2.6.ppc64_test.orig/arch/powerpc/kernel/exceptions-64s.S +++ linux-2.6.ppc64_test/arch/powerpc/kernel/exceptions-64s.S @@ -735,6 +735,9 @@ _STATIC(do_hash_page) std r3,_DAR(r1) std r4,_DSISR(r1) + andis. r0,r4,0x0040 /* Data Address Breakpoint match? */ + bne- handle_dabr_fault + andis. r0,r4,0xa450 /* weird error? */ bne- handle_page_fault /* if not, try to insert a HPTE */ BEGIN_FTR_SECTION @@ -823,6 +826,15 @@ END_FW_FTR_SECTION_IFCLR(FW_FEATURE_ISER bl .raw_local_irq_restore b 11f +/* We have a data breakpoint exception - handle it */ +handle_dabr_fault: + /* Populate the pt_regs structure */ + ld r4,_DAR(r1) + ld r5,_DSISR(r1) + addi r3,r1,STACK_FRAME_OVERHEAD + bl .do_dabr + b .ret_from_except_lite + /* Here we have a page fault that hash_page can't handle. */ handle_page_fault: ENABLE_INTS Index: linux-2.6.ppc64_test/arch/powerpc/mm/fault.c =================================================================== --- linux-2.6.ppc64_test.orig/arch/powerpc/mm/fault.c +++ linux-2.6.ppc64_test/arch/powerpc/mm/fault.c @@ -151,7 +151,7 @@ int __kprobes do_page_fault(struct pt_re if (!user_mode(regs) && (address >= TASK_SIZE)) return SIGSEGV; -#if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE)) +#if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE) || defined(CONFIG_PPC64)) if (error_code & DSISR_DABRMATCH) { /* DABR match */ do_dabr(regs, address, error_code);