From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752398AbdKVCcm (ORCPT ); Tue, 21 Nov 2017 21:32:42 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:56809 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751878AbdKVCUY (ORCPT ); Tue, 21 Nov 2017 21:20:24 -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, linux-mips@linux-mips.org, "Matt Redfearn" , "Ralf Baechle" , "Marcin Nowakowski" , "James Hogan" , "Miodrag Dinic" , "Paul Burton" , "David Daney" , "Ingo Molnar" Date: Wed, 22 Nov 2017 01:58:13 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 095/133] MIPS: microMIPS: Fix decoding of swsp16 instruction In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.51-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Matt Redfearn commit cea8cd498f4f1c30ea27e3664b3c671e495c4fce upstream. When the immediate encoded in the instruction is accessed, it is sign extended due to being a signed value being assigned to a signed integer. The ISA specifies that this operation is an unsigned operation. The sign extension leads us to incorrectly decode: 801e9c8e: cbf1 sw ra,68(sp) As having an immediate of 1073741809. Since the instruction format does not specify signed/unsigned, and this is currently the only location to use this instuction format, change it to an unsigned immediate. Fixes: bb9bc4689b9c ("MIPS: Calculate microMIPS ra properly when unwinding the stack") Suggested-by: Paul Burton Signed-off-by: Matt Redfearn Reviewed-by: James Hogan Cc: Marcin Nowakowski Cc: Miodrag Dinic Cc: Ingo Molnar Cc: David Daney Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/16957/ Signed-off-by: Ralf Baechle Signed-off-by: Ben Hutchings --- arch/mips/include/uapi/asm/inst.h | 2 +- arch/mips/kernel/process.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) --- a/arch/mips/include/uapi/asm/inst.h +++ b/arch/mips/include/uapi/asm/inst.h @@ -808,7 +808,7 @@ struct mm16_r3_format { /* Load from gl struct mm16_r5_format { /* Load/store from stack pointer format */ __BITFIELD_FIELD(unsigned int opcode : 6, __BITFIELD_FIELD(unsigned int rt : 5, - __BITFIELD_FIELD(signed int simmediate : 5, + __BITFIELD_FIELD(unsigned int imm : 5, __BITFIELD_FIELD(unsigned int : 16, /* Ignored */ ;)))) }; --- a/arch/mips/kernel/process.c +++ b/arch/mips/kernel/process.c @@ -241,7 +241,7 @@ static inline int is_ra_save_ins(union m if (ip->mm16_r5_format.rt != 31) return 0; - *poff = ip->mm16_r5_format.simmediate; + *poff = ip->mm16_r5_format.imm; *poff = (*poff << 2) / sizeof(ulong); return 1;