From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E3C91C47247 for ; Tue, 5 May 2020 14:22:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C809E20675 for ; Tue, 5 May 2020 14:22:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730188AbgEEOWi (ORCPT ); Tue, 5 May 2020 10:22:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48720 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1729613AbgEEOOh (ORCPT ); Tue, 5 May 2020 10:14:37 -0400 Received: from Galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6449EC061A0F for ; Tue, 5 May 2020 07:14:37 -0700 (PDT) Received: from p5de0bf0b.dip0.t-ipconnect.de ([93.224.191.11] helo=nanos.tec.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1jVyKx-0000zS-JQ; Tue, 05 May 2020 16:14:19 +0200 Received: from nanos.tec.linutronix.de (localhost [IPv6:::1]) by nanos.tec.linutronix.de (Postfix) with ESMTP id 0E56AFFC8D; Tue, 5 May 2020 16:14:19 +0200 (CEST) Message-Id: <20200505134340.611961721@linutronix.de> User-Agent: quilt/0.65 Date: Tue, 05 May 2020 15:41:17 +0200 From: Thomas Gleixner To: LKML Cc: x86@kernel.org, "Paul E. McKenney" , Andy Lutomirski , Alexandre Chartre , Frederic Weisbecker , Paolo Bonzini , Sean Christopherson , Masami Hiramatsu , Petr Mladek , Steven Rostedt , Joel Fernandes , Boris Ostrovsky , Juergen Gross , Brian Gerst , Mathieu Desnoyers , Josh Poimboeuf , Will Deacon Subject: [patch V4 part 2 05/18] x86/entry: Move irq tracing on syscall entry to C-code References: <20200505134112.272268764@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-transfer-encoding: 8-bit X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Now that the C entry points are safe, move the irq flags tracing code into the entry helper: - Invoke lockdep before calling into context tracking - Use the safe trace_hardirqs_on_prepare() trace function after context tracking established state and RCU is watching. Signed-off-by: Thomas Gleixner --- arch/x86/entry/common.c | 21 +++++++++++++++++++-- arch/x86/entry/entry_32.S | 12 ------------ arch/x86/entry/entry_64.S | 2 -- arch/x86/entry/entry_64_compat.S | 18 ------------------ 4 files changed, 19 insertions(+), 34 deletions(-) --- a/arch/x86/entry/common.c +++ b/arch/x86/entry/common.c @@ -40,19 +40,36 @@ #include #ifdef CONFIG_CONTEXT_TRACKING -/* Called on entry from user mode with IRQs off. */ +/** + * enter_from_user_mode - Establish state when coming from user mode + * + * Syscall entry disables interrupts, but user mode is traced as interrupts + * enabled. Also with NO_HZ_FULL RCU might be idle. + * + * 1) Tell lockdep that interrupts are disabled + * 2) Invoke context tracking if enabled to reactivate RCU + * 3) Trace interrupts off state + */ __visible noinstr void enter_from_user_mode(void) { enum ctx_state state = ct_state(); + lockdep_hardirqs_off(CALLER_ADDR0); user_exit_irqoff(); instr_begin(); CT_WARN_ON(state != CONTEXT_USER); + trace_hardirqs_off_prepare(); instr_end(); } #else -static inline void enter_from_user_mode(void) {} +static __always_inline void enter_from_user_mode(void) +{ + lockdep_hardirqs_off(CALLER_ADDR0); + instr_begin(); + trace_hardirqs_off_prepare(); + instr_end(); +} #endif static noinstr void exit_to_user_mode(void) --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -967,12 +967,6 @@ SYM_FUNC_START(entry_SYSENTER_32) jnz .Lsysenter_fix_flags .Lsysenter_flags_fixed: - /* - * User mode is traced as though IRQs are on, and SYSENTER - * turned them off. - */ - TRACE_IRQS_OFF - movl %esp, %eax call do_fast_syscall_32 /* XEN PV guests always use IRET path */ @@ -1082,12 +1076,6 @@ SYM_FUNC_START(entry_INT80_32) SAVE_ALL pt_regs_ax=$-ENOSYS switch_stacks=1 /* save rest */ - /* - * User mode is traced as though IRQs are on, and the interrupt gate - * turned them off. - */ - TRACE_IRQS_OFF - movl %esp, %eax call do_int80_syscall_32 .Lsyscall_32_done: --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -167,8 +167,6 @@ SYM_INNER_LABEL(entry_SYSCALL_64_after_h PUSH_AND_CLEAR_REGS rax=$-ENOSYS - TRACE_IRQS_OFF - /* IRQs are off. */ movq %rax, %rdi movq %rsp, %rsi --- a/arch/x86/entry/entry_64_compat.S +++ b/arch/x86/entry/entry_64_compat.S @@ -129,12 +129,6 @@ SYM_FUNC_START(entry_SYSENTER_compat) jnz .Lsysenter_fix_flags .Lsysenter_flags_fixed: - /* - * User mode is traced as though IRQs are on, and SYSENTER - * turned them off. - */ - TRACE_IRQS_OFF - movq %rsp, %rdi call do_fast_syscall_32 /* XEN PV guests always use IRET path */ @@ -247,12 +241,6 @@ SYM_INNER_LABEL(entry_SYSCALL_compat_aft pushq $0 /* pt_regs->r15 = 0 */ xorl %r15d, %r15d /* nospec r15 */ - /* - * User mode is traced as though IRQs are on, and SYSENTER - * turned them off. - */ - TRACE_IRQS_OFF - movq %rsp, %rdi call do_fast_syscall_32 /* XEN PV guests always use IRET path */ @@ -403,12 +391,6 @@ SYM_CODE_START(entry_INT80_compat) xorl %r15d, %r15d /* nospec r15 */ cld - /* - * User mode is traced as though IRQs are on, and the interrupt - * gate turned them off. - */ - TRACE_IRQS_OFF - movq %rsp, %rdi call do_int80_syscall_32 .Lsyscall_32_done: