From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3wnWn76d5lzDq5W for ; Wed, 14 Jun 2017 13:08:59 +1000 (AEST) Received: from pps.filterd (m0098396.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v5E38YYT021123 for ; Tue, 13 Jun 2017 23:08:57 -0400 Received: from e23smtp06.au.ibm.com (e23smtp06.au.ibm.com [202.81.31.148]) by mx0a-001b2d01.pphosted.com with ESMTP id 2b2t8yngmw-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Tue, 13 Jun 2017 23:08:57 -0400 Received: from localhost by e23smtp06.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 14 Jun 2017 13:08:54 +1000 Received: from d23av06.au.ibm.com (d23av06.au.ibm.com [9.190.235.151]) by d23relay10.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id v5E38psY8978756 for ; Wed, 14 Jun 2017 13:08:51 +1000 Received: from d23av06.au.ibm.com (localhost [127.0.0.1]) by d23av06.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id v5E38plR001286 for ; Wed, 14 Jun 2017 13:08:51 +1000 From: "Aneesh Kumar K.V" To: "Naveen N. Rao" , Michael Ellerman Cc: linuxppc-dev@lists.ozlabs.org, "Shriya R . Kulkarni" , Ravi Bangoria Subject: Re: [PATCH] powerpc64/hw_breakpoints: Handle data breakpoints in radix mode In-Reply-To: <20170613184200.22541-1-naveen.n.rao@linux.vnet.ibm.com> References: <20170613184200.22541-1-naveen.n.rao@linux.vnet.ibm.com> Date: Wed, 14 Jun 2017 08:38:43 +0530 MIME-Version: 1.0 Content-Type: text/plain Message-Id: <87r2yn1d1g.fsf@skywalker.in.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , "Naveen N. Rao" writes: > On P9, trying to use data breakpoints throws the splat shown below (*). > This is because the check for a data breakpoint in DSISR is in > do_hash_page(). Move this check to handle_page_fault() so as to catch > data breakpoints in both hash and radix MMU modes. > > While at it, also remove the label '11' that was made redundant by > commit a546498f3bf9aa ("powerpc: Call do_page_fault() with interrupts > off") > > (*) > Unable to handle kernel paging request for data at address 0xc000000000e19218 > Faulting instruction address: 0xc0000000001155e8 > cpu 0x0: Vector: 300 (Data Access) at [c0000000ef1e7b20] > pc: c0000000001155e8: find_pid_ns+0x48/0xe0 > lr: c000000000116ac4: find_task_by_vpid+0x44/0x90 > sp: c0000000ef1e7da0 > msr: 9000000000009033 > dar: c000000000e19218 > dsisr: 400000 > current = 0xc0000000f1f59700 > paca = 0xc00000000fd40000 softe: 0 irq_happened: 0x01 > pid = 1192, comm = sh > Linux version 4.12.0-rc3-nnr (root@ea605ec2993c) (gcc version 5.4.0 20160609 (Ubuntu/IBM 5.4.0-6ubuntu1~16.04.1) ) #74 SMP Tue Jun 13 16:52:49 UTC 2017 > enter ? for help > [c0000000ef1e7dc0] c000000000116ac4 find_task_by_vpid+0x44/0x90 > [c0000000ef1e7de0] c000000000108800 SyS_setpgid+0x80/0x220 > [c0000000ef1e7e30] c00000000000ba6c system_call+0x38/0xfc > --- Exception: c01 (System Call) at 00007fff94480890 > SP (7fffd91e7260) is in userspace > > Fixes: caca285e5ab4a ("powerpc/mm/radix: Use STD_MMU_64 to properly > isolate hash related code") > Reported-by: Shriya R. Kulkarni > Signed-off-by: Naveen N. Rao > --- > arch/powerpc/kernel/exceptions-64s.S | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S > index ae418b85c17c..17ee701b8336 100644 > --- a/arch/powerpc/kernel/exceptions-64s.S > +++ b/arch/powerpc/kernel/exceptions-64s.S > @@ -1411,10 +1411,8 @@ USE_TEXT_SECTION() > .balign IFETCH_ALIGN_BYTES > do_hash_page: > #ifdef CONFIG_PPC_STD_MMU_64 > - andis. r0,r4,0xa410 /* weird error? */ > + andis. r0,r4,0xa450 /* weird error? */ Can we convert that to a #define value. Ram did try to do that here. https://lists.ozlabs.org/pipermail/linuxppc-dev/2017-June/158607.html > bne- handle_page_fault /* if not, try to insert a HPTE */ > - andis. r0,r4,DSISR_DABRMATCH@h > - bne- handle_dabr_fault > CURRENT_THREAD_INFO(r11, r1) > lwz r0,TI_PREEMPT(r11) /* If we're in an "NMI" */ > andis. r0,r0,NMI_MASK@h /* (i.e. an irq when soft-disabled) */ > @@ -1442,7 +1440,9 @@ do_hash_page: > > /* Here we have a page fault that hash_page can't handle. */ > handle_page_fault: > -11: ld r4,_DAR(r1) > + andis. r0,r4,DSISR_DABRMATCH@h > + bne- handle_dabr_fault > + ld r4,_DAR(r1) > ld r5,_DSISR(r1) > addi r3,r1,STACK_FRAME_OVERHEAD > bl do_page_fault > -- > 2.12.2 -aneesh