Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752667AbdFHAKv (ORCPT ); Wed, 7 Jun 2017 20:10:51 -0400 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:50158 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752113AbdFGXCQ (ORCPT ); Wed, 7 Jun 2017 19:02:16 -0400 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux@roeck-us.net Cc: Paul Burton , Leonid Yegoshin , linux-mips@linux-mips.org, Ralf Baechle , Willy Tarreau Subject: [PATCH 3.10 142/250] MIPS: Clear ISA bit correctly in get_frame_info() Date: Thu, 8 Jun 2017 00:58:48 +0200 Message-Id: <1496876436-32402-143-git-send-email-w@1wt.eu> X-Mailer: git-send-email 2.8.0.rc2.1.gbe9624a In-Reply-To: <1496876436-32402-1-git-send-email-w@1wt.eu> References: <1496876436-32402-1-git-send-email-w@1wt.eu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1954 Lines: 53 From: Paul Burton commit ccaf7caf2c73c6db920772bf08bf1d47b2170634 upstream. get_frame_info() can be called in microMIPS kernels with the ISA bit already clear. For example this happens when unwind_stack_by_address() is called because we begin with a PC that has the ISA bit set & subtract the (odd) offset from the preceding symbol (which does not have the ISA bit set). Since get_frame_info() unconditionally subtracts 1 from the PC in microMIPS kernels it incorrectly misaligns the address it then attempts to access code at, leading to an address error exception. Fix this by using msk_isa16_mode() to clear the ISA bit, which allows get_frame_info() to function regardless of whether it is provided with a PC that has the ISA bit set or not. Signed-off-by: Paul Burton Fixes: 34c2f668d0f6 ("MIPS: microMIPS: Add unaligned access support.") Cc: Leonid Yegoshin Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14528/ Signed-off-by: Ralf Baechle Signed-off-by: Willy Tarreau --- arch/mips/kernel/process.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c index c6a041d..11468a0 100644 --- a/arch/mips/kernel/process.c +++ b/arch/mips/kernel/process.c @@ -322,17 +322,14 @@ static inline int is_sp_move_ins(union mips_instruction *ip) static int get_frame_info(struct mips_frame_info *info) { -#ifdef CONFIG_CPU_MICROMIPS - union mips_instruction *ip = (void *) (((char *) info->func) - 1); -#else - union mips_instruction *ip = info->func; -#endif + union mips_instruction *ip; unsigned max_insns = info->func_size / sizeof(union mips_instruction); unsigned i; info->pc_offset = -1; info->frame_size = 0; + ip = (void *)msk_isa16_mode((ulong)info->func); if (!ip) goto err; -- 2.8.0.rc2.1.gbe9624a