From patchwork Mon Sep 19 10:44:51 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Rutland X-Patchwork-Id: 76524 Delivered-To: patch@linaro.org Received: by 10.140.106.72 with SMTP id d66csp891836qgf; Mon, 19 Sep 2016 03:45:27 -0700 (PDT) X-Received: by 10.98.35.84 with SMTP id j81mr7806452pfj.166.1474281927832; Mon, 19 Sep 2016 03:45:27 -0700 (PDT) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id ji5si28492294pac.80.2016.09.19.03.45.27; Mon, 19 Sep 2016 03:45:27 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755144AbcISKp0 (ORCPT + 27 others); Mon, 19 Sep 2016 06:45:26 -0400 Received: from foss.arm.com ([217.140.101.70]:58656 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750745AbcISKpS (ORCPT ); Mon, 19 Sep 2016 06:45:18 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 5B0AC17C; Mon, 19 Sep 2016 03:45:17 -0700 (PDT) Received: from leverpostej (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 155DC3F251; Mon, 19 Sep 2016 03:45:14 -0700 (PDT) Date: Mon, 19 Sep 2016 11:44:51 +0100 From: Mark Rutland To: Andy Lutomirski , Yoshinori Sato Cc: "linux-arm-kernel@lists.infradead.org" , Andrew Morton , Ard Biesheuvel , Catalin Marinas , james.morse@arm.com, Kees Cook , "linux-kernel@vger.kernel.org" , lorenzo.pieralisi@arm.com, Andrew Lutomirski , suzuki.poulose@arm.com, Takahiro Akashi , Will Deacon , "kernel-hardening@lists.openwall.com" Subject: Re: [RFC PATCH 2/8] thread_info: allow custom in-task thread_info Message-ID: <20160919104254.GA12473@leverpostej> References: <1473947349-14521-1-git-send-email-mark.rutland@arm.com> <1473947349-14521-3-git-send-email-mark.rutland@arm.com> <20160916103101.GA21702@leverpostej> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [Adding Yosinori Sato for h8300] On Fri, Sep 16, 2016 at 08:11:14AM -0700, Andy Lutomirski wrote: > > On Thu, Sep 15, 2016 at 11:37:47AM -0700, Andy Lutomirski wrote: > > > On Thu, Sep 15, 2016 at 6:49 AM, Mark Rutland wrote: > > Just to check, what do you mean to happen with the flags field? Should > > that always be in the generic thread_info? e.g. > > > > struct thread_info { > > u32 flags; > > #ifdef arch_thread_info > > struct arch_thread_info arch_ti; > > #endif > > }; > > Exactly. Possibly with a comment that using thread_struct should be > preferred and that arch_thread_info should be used only if some header > file requires access via current_thread_info() or task_thread_info(). Sure thing. While looking at that, I spotted that would cause a circular include on h8300, but that appears to be because of a larger bug anyhow. It seems h8300 has thread_info::restart_block, and manipulates this in its signal code, yet core code manipulates task_struct::restart_block. I think we need something like the below (which is completely untested). Thanks, Mark. ---->8---- >From 4dfbdc7706bfb03a48999ff69e85e0c7361adffe Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Mon, 19 Sep 2016 11:33:42 +0100 Subject: [PATCH] h8300: fix syscall restarting Back in commit f56141e3e2d9aabf ("all arches, signal: move restart_block to struct task_struct"), all architectures and core code were changed to use task_struct::restart_block. However, when h8300 support was subsequently restored in v4.2, it was not updated to account for this, and maintains thread_info::restart_block, which is not kept in sync. This patch drops the redundant restart_block from thread_info, and moves h8300 to the common one in task_struct, ensuring that syscall restarting always works as expected. Signed-off-by: Mark Rutland Cc: Andy Lutomirski Cc: Yoshinori Sato Cc: stable@vger.kernel.org # v4.2+ --- arch/h8300/include/asm/thread_info.h | 4 ---- arch/h8300/kernel/signal.c | 2 +- 2 files changed, 1 insertion(+), 5 deletions(-) -- 1.9.1 diff --git a/arch/h8300/include/asm/thread_info.h b/arch/h8300/include/asm/thread_info.h index b408fe6..3cef068 100644 --- a/arch/h8300/include/asm/thread_info.h +++ b/arch/h8300/include/asm/thread_info.h @@ -31,7 +31,6 @@ struct thread_info { int cpu; /* cpu we're on */ int preempt_count; /* 0 => preemptable, <0 => BUG */ mm_segment_t addr_limit; - struct restart_block restart_block; }; /* @@ -44,9 +43,6 @@ struct thread_info { .cpu = 0, \ .preempt_count = INIT_PREEMPT_COUNT, \ .addr_limit = KERNEL_DS, \ - .restart_block = { \ - .fn = do_no_restart_syscall, \ - }, \ } #define init_thread_info (init_thread_union.thread_info) diff --git a/arch/h8300/kernel/signal.c b/arch/h8300/kernel/signal.c index ad1f81f..7138303 100644 --- a/arch/h8300/kernel/signal.c +++ b/arch/h8300/kernel/signal.c @@ -79,7 +79,7 @@ restore_sigcontext(struct sigcontext *usc, int *pd0) unsigned int er0; /* Always make any pending restarted system calls return -EINTR */ - current_thread_info()->restart_block.fn = do_no_restart_syscall; + current->restart_block.fn = do_no_restart_syscall; /* restore passed registers */ #define COPY(r) do { err |= get_user(regs->r, &usc->sc_##r); } while (0)