From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752516AbdF0Oj1 (ORCPT ); Tue, 27 Jun 2017 10:39:27 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:55600 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751479AbdF0ONj (ORCPT ); Tue, 27 Jun 2017 10:13:39 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Shriya R. Kulkarni" , "Naveen N. Rao" , Michael Ellerman Subject: [PATCH 4.9 19/44] powerpc/64s: Handle data breakpoints in Radix mode Date: Tue, 27 Jun 2017 16:12:31 +0200 Message-Id: <20170627141108.790264424@linuxfoundation.org> X-Mailer: git-send-email 2.13.2 In-Reply-To: <20170627141107.865578528@linuxfoundation.org> References: <20170627141107.865578528@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Naveen N. Rao commit d89ba5353f301971dd7d2f9fdf25c4432728f38e upstream. On Power9, 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(), which is not called when in Radix mode. 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 Move the check to handle_page_fault() so as to catch data breakpoints in both Hash and Radix MMU modes. We have to change the check in do_hash_page() against 0xa410 to use 0xa450, so as to include the value of (DSISR_DABRMATCH << 16). There are two sites that call handle_page_fault() when in Radix, both already pass DSISR in r4. Fixes: caca285e5ab4 ("powerpc/mm/radix: Use STD_MMU_64 to properly isolate hash related code") Reported-by: Shriya R. Kulkarni Signed-off-by: Naveen N. Rao [mpe: Fix the fall-through case on hash, we need to reload DSISR] Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/kernel/exceptions-64s.S | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -1411,10 +1411,8 @@ USE_TEXT_SECTION() .align 7 do_hash_page: #ifdef CONFIG_PPC_STD_MMU_64 - andis. r0,r4,0xa410 /* weird error? */ + andis. r0,r4,0xa450 /* weird error? */ 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) */ @@ -1438,11 +1436,16 @@ do_hash_page: /* Error */ blt- 13f + + /* Reload DSISR into r4 for the DABR check below */ + ld r4,_DSISR(r1) #endif /* CONFIG_PPC_STD_MMU_64 */ /* Here we have a page fault that hash_page can't handle. */ handle_page_fault: -11: ld r4,_DAR(r1) +11: 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