From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:60500 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751058AbcFDRG3 (ORCPT ); Sat, 4 Jun 2016 13:06:29 -0400 Subject: Patch "MIPS: math-emu: Fix jalr emulation when rd == $0" has been added to the 3.14-stable tree To: paul.burton@imgtec.com, gregkh@linuxfoundation.org, james.hogan@imgtec.com, macro@imgtec.com, ralf@linux-mips.org Cc: , From: Date: Sat, 04 Jun 2016 10:06:27 -0700 Message-ID: <1465059987128155@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 MIPS: math-emu: Fix jalr emulation when rd == $0 to the 3.14-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: mips-math-emu-fix-jalr-emulation-when-rd-0.patch and it can be found in the queue-3.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From ab4a92e66741b35ca12f8497896bafbe579c28a1 Mon Sep 17 00:00:00 2001 From: Paul Burton Date: Thu, 21 Apr 2016 14:04:55 +0100 Subject: MIPS: math-emu: Fix jalr emulation when rd == $0 From: Paul Burton commit ab4a92e66741b35ca12f8497896bafbe579c28a1 upstream. When emulating a jalr instruction with rd == $0, the code in isBranchInstr was incorrectly writing to GPR $0 which should actually always remain zeroed. This would lead to any further instructions emulated which use $0 operating on a bogus value until the task is next context switched, at which point the value of $0 in the task context would be restored to the correct zero by a store in SAVE_SOME. Fix this by not writing to rd if it is $0. Fixes: 102cedc32a6e ("MIPS: microMIPS: Floating point support.") Signed-off-by: Paul Burton Cc: Maciej W. Rozycki Cc: James Hogan Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/13160/ Signed-off-by: Ralf Baechle Signed-off-by: Greg Kroah-Hartman --- arch/mips/math-emu/cp1emu.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) --- a/arch/mips/math-emu/cp1emu.c +++ b/arch/mips/math-emu/cp1emu.c @@ -676,9 +676,11 @@ static int isBranchInstr(struct pt_regs case spec_op: switch (insn.r_format.func) { case jalr_op: - regs->regs[insn.r_format.rd] = - regs->cp0_epc + dec_insn.pc_inc + - dec_insn.next_pc_inc; + if (insn.r_format.rd != 0) { + regs->regs[insn.r_format.rd] = + regs->cp0_epc + dec_insn.pc_inc + + dec_insn.next_pc_inc; + } /* Fall through */ case jr_op: *contpc = regs->regs[insn.r_format.rs]; Patches currently in stable-queue which might be from paul.burton@imgtec.com are queue-3.14/mips-math-emu-fix-jalr-emulation-when-rd-0.patch