From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mark Rutland , Will Deacon , Kristina Martsenko , Catalin Marinas Subject: [PATCH 4.11 149/197] arm64: hw_breakpoint: fix watchpoint matching for tagged pointers Date: Tue, 23 May 2017 22:08:30 +0200 Message-Id: <20170523200836.422801055@linuxfoundation.org> In-Reply-To: <20170523200821.666872592@linuxfoundation.org> References: <20170523200821.666872592@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.11-stable review patch. If anyone has any objections, please let me know. ------------------ 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);