From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:52200 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731209AbeKLF5O (ORCPT ); Mon, 12 Nov 2018 00:57:14 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Michael Ellerman" , "Michael Neuling" Date: Sun, 11 Nov 2018 19:49:05 +0000 Message-ID: Subject: [PATCH 3.16 069/366] powerpc/ptrace: Fix enforcement of DAWR constraints In-Reply-To: Sender: stable-owner@vger.kernel.org List-ID: 3.16.61-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Michael Neuling commit cd6ef7eebf171bfcba7dc2df719c2a4958775040 upstream. Back when we first introduced the DAWR, in commit 4ae7ebe9522a ("powerpc: Change hardware breakpoint to allow longer ranges"), we screwed up the constraint making it a 1024 byte boundary rather than a 512. This makes the check overly permissive. Fortunately GDB is the only real user and it always did they right thing, so we never noticed. This fixes the constraint to 512 bytes. Fixes: 4ae7ebe9522a ("powerpc: Change hardware breakpoint to allow longer ranges") Signed-off-by: Michael Neuling Signed-off-by: Michael Ellerman Signed-off-by: Ben Hutchings --- arch/powerpc/kernel/hw_breakpoint.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/arch/powerpc/kernel/hw_breakpoint.c +++ b/arch/powerpc/kernel/hw_breakpoint.c @@ -174,8 +174,8 @@ int arch_validate_hwbkpt_settings(struct if (cpu_has_feature(CPU_FTR_DAWR)) { length_max = 512 ; /* 64 doublewords */ /* DAWR region can't cross 512 boundary */ - if ((bp->attr.bp_addr >> 10) != - ((bp->attr.bp_addr + bp->attr.bp_len - 1) >> 10)) + if ((bp->attr.bp_addr >> 9) != + ((bp->attr.bp_addr + bp->attr.bp_len - 1) >> 9)) return -EINVAL; } if (info->len >