From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from aserp1040.oracle.com ([141.146.126.69]:50566 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1422666AbcFCVjD (ORCPT ); Fri, 3 Jun 2016 17:39:03 -0400 From: Sasha Levin To: stable@vger.kernel.org, stable-commits@vger.kernel.org Cc: Paul Burton , Adam Buchbinder , James Hogan , linux-mips@linux-mips.org, linux-kernel@vger.kernel.org, Ralf Baechle , Sasha Levin Subject: [added to the 4.1 stable tree] MIPS: Disable preemption during prctl(PR_SET_FP_MODE, ...) Date: Fri, 3 Jun 2016 17:36:31 -0400 Message-Id: <1464989831-16666-96-git-send-email-sasha.levin@oracle.com> In-Reply-To: <1464989831-16666-1-git-send-email-sasha.levin@oracle.com> References: <1464989831-16666-1-git-send-email-sasha.levin@oracle.com> Sender: stable-owner@vger.kernel.org List-ID: From: Paul Burton This patch has been added to the 4.1 stable tree. If you have any objections, please let us know. =============== [ Upstream commit bd239f1e1429e7781096bf3884bdb1b2b1bb4f28 ] Whilst a PR_SET_FP_MODE prctl is performed there are decisions made based upon whether the task is executing on the current CPU. This may change if we're preempted, so disable preemption to avoid such changes for the lifetime of the mode switch. Signed-off-by: Paul Burton Fixes: 9791554b45a2 ("MIPS,prctl: add PR_[GS]ET_FP_MODE prctl options for MIPS") Reviewed-by: Maciej W. Rozycki Tested-by: Aurelien Jarno Cc: Adam Buchbinder Cc: James Hogan Cc: stable # v4.0+ Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/13144/ Signed-off-by: Ralf Baechle Signed-off-by: Sasha Levin --- arch/mips/kernel/process.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c index 6b3ae73..89847be 100644 --- a/arch/mips/kernel/process.c +++ b/arch/mips/kernel/process.c @@ -603,6 +603,9 @@ int mips_set_process_fp_mode(struct task_struct *task, unsigned int value) if (!(value & PR_FP_MODE_FR) && cpu_has_fpu && cpu_has_mips_r6) return -EOPNOTSUPP; + /* Proceed with the mode switch */ + preempt_disable(); + /* Save FP & vector context, then disable FPU & MSA */ if (task->signal == current->signal) lose_fpu(1); @@ -661,6 +664,7 @@ int mips_set_process_fp_mode(struct task_struct *task, unsigned int value) /* Allow threads to use FP again */ atomic_set(&task->mm->context.fp_mode_switching, 0); + preempt_enable(); return 0; } -- 2.5.0