From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:50416 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750732AbdHaGUJ (ORCPT ); Thu, 31 Aug 2017 02:20:09 -0400 Subject: Patch "arm64: flush FP/SIMD state correctly after execve()" has been added to the 3.18-stable tree To: ard.biesheuvel@linaro.org, chunyan.zhang@spreadtrum.com, gregkh@linuxfoundation.org, janet.liu@spreadtrum.com, will.deacon@arm.com Cc: , From: Date: Thu, 31 Aug 2017 08:20:12 +0200 Message-ID: <15041604129297@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 arm64: flush FP/SIMD state correctly after execve() to the 3.18-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: arm64-flush-fp-simd-state-correctly-after-execve.patch and it can be found in the queue-3.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 674c242c9323d3c293fc4f9a3a3a619fe3063290 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Thu, 27 Aug 2015 07:12:33 +0100 Subject: arm64: flush FP/SIMD state correctly after execve() From: Ard Biesheuvel commit 674c242c9323d3c293fc4f9a3a3a619fe3063290 upstream. When a task calls execve(), its FP/SIMD state is flushed so that none of the original program state is observeable by the incoming program. However, since this flushing consists of setting the in-memory copy of the FP/SIMD state to all zeroes, the CPU field is set to CPU 0 as well, which indicates to the lazy FP/SIMD preserve/restore code that the FP/SIMD state does not need to be reread from memory if the task is scheduled again on CPU 0 without any other tasks having entered userland (or used the FP/SIMD in kernel mode) on the same CPU in the mean time. If this happens, the FP/SIMD state of the old program will still be present in the registers when the new program starts. So set the CPU field to the invalid value of NR_CPUS when performing the flush, by calling fpsimd_flush_task_state(). Reported-by: Chunyan Zhang Reported-by: Janet Liu Signed-off-by: Ard Biesheuvel Signed-off-by: Will Deacon Signed-off-by: Greg Kroah-Hartman --- arch/arm64/kernel/fpsimd.c | 1 + 1 file changed, 1 insertion(+) --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -157,6 +157,7 @@ void fpsimd_thread_switch(struct task_st void fpsimd_flush_thread(void) { memset(¤t->thread.fpsimd_state, 0, sizeof(struct fpsimd_state)); + fpsimd_flush_task_state(current); set_thread_flag(TIF_FOREIGN_FPSTATE); } Patches currently in stable-queue which might be from ard.biesheuvel@linaro.org are queue-3.18/arm64-flush-fp-simd-state-correctly-after-execve.patch queue-3.18/arm64-fpsimd-prevent-registers-leaking-across-exec.patch