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=-3.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 CF544C0651F for ; Thu, 4 Jul 2019 20:04:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 963C021852 for ; Thu, 4 Jul 2019 20:04:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="0B/KrdV3" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727456AbfGDUEb (ORCPT ); Thu, 4 Jul 2019 16:04:31 -0400 Received: from merlin.infradead.org ([205.233.59.134]:55242 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726903AbfGDUEb (ORCPT ); Thu, 4 Jul 2019 16:04:31 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-Id:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=d5fEomzm2WlXF0OHxmb/BtkSVx0kvKPLQ5xZaii3quE=; b=0B/KrdV3ne1ihVC83PoZrvVJHe F/ytEGMxELyTK4C2QtxDr/BTyKsaNn5xk+4NsaWDDuXk1hnridqkFmnjGsdnIgP9m8s+1/PwWEQe4 pOtuy6AmoTHc35ybj6pCiz7MGc9sHE55tnqnS+R8eaY2zW2HbqZCSY2KLPJhlLbs4nKEsQTw9otOi 1N0Xv3waoWnB14Rki6Q9kEviS1zNH8F03JNynswDGRRcieSKjV1l0SYxBmU1WhkFtyYJpIlov/8g0 CkwV3w+wqgsBIbj2yhPvy9SBfqB1Oar3YpYtuu5bqLJz2tE07ebFJ6k4cCFNH/OkdCyOoJaBD1Kho H11Z9B/Q==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92 #3 (Red Hat Linux)) id 1hj7wb-0005ei-Aq; Thu, 04 Jul 2019 20:03:01 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id 5369D2059DEDC; Thu, 4 Jul 2019 22:02:58 +0200 (CEST) Message-Id: <20190704200050.591915266@infradead.org> User-Agent: quilt/0.65 Date: Thu, 04 Jul 2019 21:56:01 +0200 From: Peter Zijlstra To: tglx@linutronix.de, bp@alien8.de, mingo@kernel.org, rostedt@goodmis.org, luto@kernel.org, torvalds@linux-foundation.org Cc: hpa@zytor.com, dave.hansen@linux.intel.com, jgross@suse.com, linux-kernel@vger.kernel.org, zhe.he@windriver.com, joel@joelfernandes.org, devel@etsukata.com, peterz@infradead.org Subject: [PATCH v2 6/7] x86/entry/64: Remove TRACE_IRQS_*_DEBUG References: <20190704195555.580363209@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Since INT3/#BP no longer runs on an IST, this workaround is no longer required. Tested by running lockdep+ftrace as described in the initial commit: 5963e317b1e9 ("ftrace/x86: Do not change stacks in DEBUG when calling lockdep") Signed-off-by: Peter Zijlstra (Intel) --- arch/x86/entry/entry_64.S | 46 ++-------------------------------------------- 1 file changed, 2 insertions(+), 44 deletions(-) --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -68,44 +68,6 @@ END(native_usergs_sysret64) .endm /* - * When dynamic function tracer is enabled it will add a breakpoint - * to all locations that it is about to modify, sync CPUs, update - * all the code, sync CPUs, then remove the breakpoints. In this time - * if lockdep is enabled, it might jump back into the debug handler - * outside the updating of the IST protection. (TRACE_IRQS_ON/OFF). - * - * We need to change the IDT table before calling TRACE_IRQS_ON/OFF to - * make sure the stack pointer does not get reset back to the top - * of the debug stack, and instead just reuses the current stack. - */ -#if defined(CONFIG_DYNAMIC_FTRACE) && defined(CONFIG_TRACE_IRQFLAGS) - -.macro TRACE_IRQS_OFF_DEBUG - call debug_stack_set_zero - TRACE_IRQS_OFF - call debug_stack_reset -.endm - -.macro TRACE_IRQS_ON_DEBUG - call debug_stack_set_zero - TRACE_IRQS_ON - call debug_stack_reset -.endm - -.macro TRACE_IRQS_IRETQ_DEBUG - btl $9, EFLAGS(%rsp) /* interrupts off? */ - jnc 1f - TRACE_IRQS_ON_DEBUG -1: -.endm - -#else -# define TRACE_IRQS_OFF_DEBUG TRACE_IRQS_OFF -# define TRACE_IRQS_ON_DEBUG TRACE_IRQS_ON -# define TRACE_IRQS_IRETQ_DEBUG TRACE_IRQS_IRETQ -#endif - -/* * 64-bit SYSCALL instruction entry. Up to 6 arguments in registers. * * This is the only entry point used for 64-bit system calls. The @@ -879,11 +841,7 @@ apicinterrupt IRQ_WORK_VECTOR irq_work GET_CR2_INTO(%rdx); /* can clobber %rax */ .endif - .if \shift_ist != -1 - TRACE_IRQS_OFF_DEBUG /* reload IDT in case of recursion */ - .else TRACE_IRQS_OFF - .endif .if \paranoid == 0 testb $3, CS(%rsp) @@ -1292,7 +1250,7 @@ END(paranoid_entry) ENTRY(paranoid_exit) UNWIND_HINT_REGS DISABLE_INTERRUPTS(CLBR_ANY) - TRACE_IRQS_OFF_DEBUG + TRACE_IRQS_OFF /* Handle GS depending on FSGSBASE availability */ ALTERNATIVE "jmp .Lparanoid_exit_checkgs", "nop",X86_FEATURE_FSGSBASE @@ -1312,7 +1270,7 @@ ENTRY(paranoid_exit) jmp .Lparanoid_exit_restore .Lparanoid_exit_no_swapgs: - TRACE_IRQS_IRETQ_DEBUG + TRACE_IRQS_IRETQ /* Always restore stashed CR3 value (see paranoid_entry) */ RESTORE_CR3 scratch_reg=%rbx save_reg=%r14