From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f69.google.com (mail-oi0-f69.google.com [209.85.218.69]) by kanga.kvack.org (Postfix) with ESMTP id 07B9C6B0260 for ; Wed, 31 Aug 2016 10:08:59 -0400 (EDT) Received: by mail-oi0-f69.google.com with SMTP id l205so13933456oia.1 for ; Wed, 31 Aug 2016 07:08:59 -0700 (PDT) Received: from EUR01-HE1-obe.outbound.protection.outlook.com (mail-he1eur01on0102.outbound.protection.outlook.com. [104.47.0.102]) by mx.google.com with ESMTPS id e37si51667otc.184.2016.08.31.07.01.59 for (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Wed, 31 Aug 2016 07:01:59 -0700 (PDT) From: Dmitry Safonov Subject: [PATCHv4 5/6] x86/ptrace: down with test_thread_flag(TIF_IA32) Date: Wed, 31 Aug 2016 16:59:35 +0300 Message-ID: <20160831135936.2281-6-dsafonov@virtuozzo.com> In-Reply-To: <20160831135936.2281-1-dsafonov@virtuozzo.com> References: <20160831135936.2281-1-dsafonov@virtuozzo.com> MIME-Version: 1.0 Content-Type: text/plain Sender: owner-linux-mm@kvack.org List-ID: To: linux-kernel@vger.kernel.org Cc: 0x7f454c46@gmail.com, luto@kernel.org, oleg@redhat.com, tglx@linutronix.de, hpa@zytor.com, mingo@redhat.com, linux-mm@kvack.org, x86@kernel.org, gorcunov@openvz.org, xemul@virtuozzo.com, Dmitry Safonov , Pedro Alves As the task isn't executing at the moment of {GET,SET}REGS, return regset that corresponds to code selector, rather than value of TIF_IA32 flag. I.e. if we ptrace i386 elf binary that has just changed it's code selector to __USER_CS, than GET_REGS will return full x86_64 register set. Note, that this will work only if application has changed it's CS. If the application does 32-bit syscall with __USER_CS, ptrace will still return 64-bit register set. Which might be still confusing for tools that expect TS_COMPACT to be exposed [1, 2]. So this this change should make PTRACE_GETREGSET more reliable and this will be another step to drop TIF_{IA32,X32} flags. [1]: https://sourceforge.net/p/strace/mailman/message/30471411/ [2]: https://lkml.org/lkml/2012/1/18/320 Cc: Andy Lutomirski Cc: Oleg Nesterov Cc: Pedro Alves Cc: Thomas Gleixner Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: linux-mm@kvack.org Cc: x86@kernel.org Cc: Cyrill Gorcunov Cc: Pavel Emelyanov Signed-off-by: Dmitry Safonov --- arch/x86/kernel/ptrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c index f79576a541ff..ad0bab8fc594 100644 --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -1358,7 +1358,7 @@ void update_regset_xstate_info(unsigned int size, u64 xstate_mask) const struct user_regset_view *task_user_regset_view(struct task_struct *task) { #ifdef CONFIG_IA32_EMULATION - if (test_tsk_thread_flag(task, TIF_IA32)) + if (!user_64bit_mode(task_pt_regs(task))) #endif #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION return &user_x86_32_view; -- 2.9.0 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org