From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:38524 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761617AbdEWOqd (ORCPT ); Tue, 23 May 2017 10:46:33 -0400 Subject: Patch "arm64: hw_breakpoint: fix watchpoint matching for tagged pointers" has been added to the 4.11-stable tree To: kristina.martsenko@arm.com, catalin.marinas@arm.com, gregkh@linuxfoundation.org, mark.rutland@arm.com, will.deacon@arm.com Cc: , From: Date: Tue, 23 May 2017 16:45:40 +0200 Message-ID: <149555074033204@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled arm64: hw_breakpoint: fix watchpoint matching for tagged pointers to the 4.11-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: arm64-hw_breakpoint-fix-watchpoint-matching-for-tagged-pointers.patch and it can be found in the queue-4.11 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 7dcd9dd8cebe9fa626af7e2358d03a37041a70fb Mon Sep 17 00:00:00 2001 From: Kristina Martsenko Date: Wed, 3 May 2017 16:37:46 +0100 Subject: arm64: hw_breakpoint: fix watchpoint matching for tagged pointers From: Kristina Martsenko commit 7dcd9dd8cebe9fa626af7e2358d03a37041a70fb upstream. When we take a watchpoint exception, the address that triggered the watchpoint is found in FAR_EL1. We compare it to the address of each configured watchpoint to see which one was hit. The configured watchpoint addresses are untagged, while the address in FAR_EL1 will have an address tag if the data access was done using a tagged address. The tag needs to be removed to compare the address to the watchpoints. Currently we don't remove it, and as a result can report the wrong watchpoint as being hit (specifically, always either the highest TTBR0 watchpoint or lowest TTBR1 watchpoint). This patch removes the tag. Fixes: d50240a5f6ce ("arm64: mm: permit use of tagged pointers at EL0") Acked-by: Mark Rutland Acked-by: Will Deacon Signed-off-by: Kristina Martsenko Signed-off-by: Catalin Marinas Signed-off-by: Greg Kroah-Hartman --- arch/arm64/include/asm/uaccess.h | 6 +++--- arch/arm64/kernel/hw_breakpoint.c | 3 +++ 2 files changed, 6 insertions(+), 3 deletions(-) --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -107,9 +107,9 @@ static inline void set_fs(mm_segment_t f }) /* - * When dealing with data aborts or instruction traps we may end up with - * a tagged userland pointer. Clear the tag to get a sane pointer to pass - * on to access_ok(), for instance. + * When dealing with data aborts, watchpoints, or instruction traps we may end + * up with a tagged userland pointer. Clear the tag to get a sane pointer to + * pass on to access_ok(), for instance. */ #define untagged_addr(addr) sign_extend64(addr, 55) --- a/arch/arm64/kernel/hw_breakpoint.c +++ b/arch/arm64/kernel/hw_breakpoint.c @@ -36,6 +36,7 @@ #include #include #include +#include /* Breakpoint currently in use for each BRP. */ static DEFINE_PER_CPU(struct perf_event *, bp_on_reg[ARM_MAX_BRP]); @@ -721,6 +722,8 @@ static u64 get_distance_from_watchpoint( u64 wp_low, wp_high; u32 lens, lene; + addr = untagged_addr(addr); + lens = __ffs(ctrl->len); lene = __fls(ctrl->len); Patches currently in stable-queue which might be from kristina.martsenko@arm.com are queue-4.11/arm64-hw_breakpoint-fix-watchpoint-matching-for-tagged-pointers.patch queue-4.11/arm64-entry-improve-data-abort-handling-of-tagged-pointers.patch queue-4.11/arm64-documentation-document-tagged-pointer-stack-constraints.patch queue-4.11/arm64-traps-fix-userspace-cache-maintenance-emulation-on-a-tagged-pointer.patch