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=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 7CFFBCA9EB9 for ; Wed, 23 Oct 2019 21:31:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 44A902173B for ; Wed, 23 Oct 2019 21:31:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1571866267; bh=bq0xL50hpqaPXcNSOUfqCHdzo65lRDo//Gm6bz69RZs=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=hbHBu+G4WoXntbGKm36j7eENGWD5E4rIL733+vXzKKmfH5qCH5ThOQId8ZXicHrJM qNt2Dk44I0iZlh2D6c1e4h6RlNOq9YDg8IP35fNt6rFZCHjqvJ3tw96upbz0y0KeCB RSZywsEjNOdj0iuhqmJQrfSHmJAUZYo9KPPHdjtI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392663AbfJWVbF (ORCPT ); Wed, 23 Oct 2019 17:31:05 -0400 Received: from mail.kernel.org ([198.145.29.99]:43544 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391325AbfJWVbF (ORCPT ); Wed, 23 Oct 2019 17:31:05 -0400 Received: from mail-wr1-f51.google.com (mail-wr1-f51.google.com [209.85.221.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2A60021A4A for ; Wed, 23 Oct 2019 21:31:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1571866264; bh=bq0xL50hpqaPXcNSOUfqCHdzo65lRDo//Gm6bz69RZs=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=xOoTNiJgTEkXxLm3Zw2wUubiwXf7K9pRiSbAs/YuGr7DsOZgVtWHy0apBBVtfFUef CbVcE0oAPQLm8UTtG4o1EXrWYK7DWsHtRzkrwXnODgaWsmUu9IhJsmcaPP/DQim6Ls GjdkAqyd+IeYC5RkbSD7pRoJdzmof04wqvgo5QS8= Received: by mail-wr1-f51.google.com with SMTP id s1so14900335wro.0 for ; Wed, 23 Oct 2019 14:31:04 -0700 (PDT) X-Gm-Message-State: APjAAAUwI3wQf0K97uFhOHZWZ+fghb8xBhgiL6GE+3nHj+/eLXgCm7Ud lrzHN7G/7AV/C3UIEEJl03WDn5Dn2marc7+ngr+UkA== X-Google-Smtp-Source: APXvYqxciiabhK1TgUrj4Tvuz0nMo9AovfxcBOd5U1U4aZECW+yDd2p8KX8bdYpf//9QdzEBqYuaRFnrVK7lMJnSpFM= X-Received: by 2002:adf:f342:: with SMTP id e2mr721058wrp.61.1571866262651; Wed, 23 Oct 2019 14:31:02 -0700 (PDT) MIME-Version: 1.0 References: <20191023122705.198339581@linutronix.de> <20191023123118.386844979@linutronix.de> In-Reply-To: <20191023123118.386844979@linutronix.de> From: Andy Lutomirski Date: Wed, 23 Oct 2019 14:30:51 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [patch V2 08/17] x86/entry: Move syscall irq tracing to C code To: Thomas Gleixner Cc: LKML , X86 ML , Peter Zijlstra , Andy Lutomirski , Will Deacon , Paolo Bonzini , kvm list , linux-arch , Mike Rapoport , Josh Poimboeuf , Miroslav Benes Content-Type: multipart/mixed; boundary="00000000000038b2b005959aa2c3" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --00000000000038b2b005959aa2c3 Content-Type: text/plain; charset="UTF-8" On Wed, Oct 23, 2019 at 5:31 AM Thomas Gleixner wrote: > > Interrupt state tracing can be safely done in C code. The few stack > operations in assembly do not need to be covered. > > Remove the now pointless indirection via .Lsyscall_32_done and jump to > swapgs_restore_regs_and_return_to_usermode directly. This doesn't look right. > #define SYSCALL_EXIT_WORK_FLAGS \ > @@ -279,6 +282,9 @@ static void syscall_slow_exit_work(struc > { > struct thread_info *ti; > > + /* User to kernel transition disabled interrupts. */ > + trace_hardirqs_off(); > + So you just traced IRQs off, but... > enter_from_user_mode(); > local_irq_enable(); Now they're on and traced on again? I also don't see how your patch handles the fastpath case. How about the attached patch instead? --00000000000038b2b005959aa2c3 Content-Type: text/x-patch; charset="US-ASCII"; name="irqtrace.patch" Content-Disposition: attachment; filename="irqtrace.patch" Content-Transfer-Encoding: base64 Content-ID: X-Attachment-Id: f_k23sk6dd0 Y29tbWl0IGUxNTRhZjBkN2ZmMmQ2MDVmMTU1ZjVhY2EwNTllM2U4MzVlNDI2ZDQKQXV0aG9yOiBB bmR5IEx1dG9taXJza2kgPGx1dG9Aa2VybmVsLm9yZz4KRGF0ZTogICBGcmkgQXVnIDIgMTA6MzA6 NDQgMjAxOSAtMDcwMAoKICAgIHg4Ni9lbnRyeTogTW92ZSBleGl0LXRvLXVzZXJtb2RlIGlycWZs YWcgdHJhY2luZyB0byBwcmVwYXJlX2V4aXRfdG9fdXNlcm1vZGUoKQogICAgCiAgICBwcmVwYXJl X2V4aXRfdG9fdXNlcm1vZGUoKSBjYW4gZWFzaWx5IGhhbmRsZSBpcnFmbGFnIHRyYWNpbmcuICBN b3ZlCiAgICB0aGUgbG9naWMgdGhlcmUgYW5kIHJlbW92ZSBpdCBmcm9tIHRoZSBlbnRyeSBhc20u CiAgICAKICAgIFNpZ25lZC1vZmYtYnk6IEFuZHkgTHV0b21pcnNraSA8bHV0b0BrZXJuZWwub3Jn PgoKZGlmZiAtLWdpdCBhL2FyY2gveDg2L2VudHJ5L2NvbW1vbi5jIGIvYXJjaC94ODYvZW50cnkv Y29tbW9uLmMKaW5kZXggY2M0OTM4MGVmOGFiLi5mNGNlMGNmMmZiNzQgMTAwNjQ0Ci0tLSBhL2Fy Y2gveDg2L2VudHJ5L2NvbW1vbi5jCisrKyBiL2FyY2gveDg2L2VudHJ5L2NvbW1vbi5jCkBAIC0y MTcsNiArMjE3LDEzIEBAIF9fdmlzaWJsZSBpbmxpbmUgdm9pZCBwcmVwYXJlX2V4aXRfdG9fdXNl cm1vZGUoc3RydWN0IHB0X3JlZ3MgKnJlZ3MpCiAKIAl1c2VyX2VudGVyX2lycW9mZigpOwogCisJ LyoKKwkgKiBUaGUgYWN0dWFsIHJldHVybiB0byB1c2VybW9kZSB3aWxsIGFsbW9zdCBjZXJ0YWlu bHkgdHVybiBJUlFzIG9uLgorCSAqIFRyYWNlIGl0IGhlcmUgdG8gc2ltcGxpZnkgdGhlIGFzbSBj b2RlLgorCSAqLworCWlmIChsaWtlbHkocmVncy0+ZmxhZ3MgJiBYODZfRUZMQUdTX0lGKSkKKwkJ dHJhY2VfaGFyZGlycXNfb24oKTsKKwogCW1kc191c2VyX2NsZWFyX2NwdV9idWZmZXJzKCk7CiB9 CiAKZGlmZiAtLWdpdCBhL2FyY2gveDg2L2VudHJ5L2VudHJ5XzMyLlMgYi9hcmNoL3g4Ni9lbnRy eS9lbnRyeV8zMi5TCmluZGV4IGY4M2NhNWFhOGI3Ny4uYzcwM2MyOWJlYmIxIDEwMDY0NAotLS0g YS9hcmNoL3g4Ni9lbnRyeS9lbnRyeV8zMi5TCisrKyBiL2FyY2gveDg2L2VudHJ5L2VudHJ5XzMy LlMKQEAgLTEwNjIsNyArMTA2Miw2IEBAIEVOVFJZKGVudHJ5X0lOVDgwXzMyKQogCVNUQUNLTEVB S19FUkFTRQogCiByZXN0b3JlX2FsbDoKLQlUUkFDRV9JUlFTX0lSRVQKIAlTV0lUQ0hfVE9fRU5U UllfU1RBQ0sKIC5McmVzdG9yZV9hbGxfbm90cmFjZToKIAlDSEVDS19BTkRfQVBQTFlfRVNQRklY CmRpZmYgLS1naXQgYS9hcmNoL3g4Ni9lbnRyeS9lbnRyeV82NC5TIGIvYXJjaC94ODYvZW50cnkv ZW50cnlfNjQuUwppbmRleCAzYWJhZTgwZDQ5MDIuLjA1NjQxOWEwZTc2ZiAxMDA2NDQKLS0tIGEv YXJjaC94ODYvZW50cnkvZW50cnlfNjQuUworKysgYi9hcmNoL3g4Ni9lbnRyeS9lbnRyeV82NC5T CkBAIC0xNzIsOCArMTcyLDYgQEAgR0xPQkFMKGVudHJ5X1NZU0NBTExfNjRfYWZ0ZXJfaHdmcmFt ZSkKIAltb3ZxCSVyc3AsICVyc2kKIAljYWxsCWRvX3N5c2NhbGxfNjQJCS8qIHJldHVybnMgd2l0 aCBJUlFzIGRpc2FibGVkICovCiAKLQlUUkFDRV9JUlFTX0lSRVRRCQkvKiB3ZSdyZSBhYm91dCB0 byBjaGFuZ2UgSUYgKi8KLQogCS8qCiAJICogVHJ5IHRvIHVzZSBTWVNSRVQgaW5zdGVhZCBvZiBJ UkVUIGlmIHdlJ3JlIHJldHVybmluZyB0bwogCSAqIGEgY29tcGxldGVseSBjbGVhbiA2NC1iaXQg dXNlcnNwYWNlIGNvbnRleHQuICBJZiB3ZSdyZSBub3QsCkBAIC02MTcsNyArNjE1LDYgQEAgcmV0 X2Zyb21faW50cjoKIC5McmV0aW50X3VzZXI6CiAJbW92CSVyc3AsJXJkaQogCWNhbGwJcHJlcGFy ZV9leGl0X3RvX3VzZXJtb2RlCi0JVFJBQ0VfSVJRU19JUkVUUQogCiBHTE9CQUwoc3dhcGdzX3Jl c3RvcmVfcmVnc19hbmRfcmV0dXJuX3RvX3VzZXJtb2RlKQogI2lmZGVmIENPTkZJR19ERUJVR19F TlRSWQpkaWZmIC0tZ2l0IGEvYXJjaC94ODYvZW50cnkvZW50cnlfNjRfY29tcGF0LlMgYi9hcmNo L3g4Ni9lbnRyeS9lbnRyeV82NF9jb21wYXQuUwppbmRleCA0MzVkZjYzN2YzOTIuLjM1MDJmMzhi ZGUwMSAxMDA2NDQKLS0tIGEvYXJjaC94ODYvZW50cnkvZW50cnlfNjRfY29tcGF0LlMKKysrIGIv YXJjaC94ODYvZW50cnkvZW50cnlfNjRfY29tcGF0LlMKQEAgLTI1NCw3ICsyNTQsNiBAQCBzeXNy ZXQzMl9mcm9tX3N5c3RlbV9jYWxsOgogCSAqIHN0YWNrLiBTbyBsZXQncyBlcmFzZSB0aGUgdGhy ZWFkIHN0YWNrIHJpZ2h0IG5vdy4KIAkgKi8KIAlTVEFDS0xFQUtfRVJBU0UKLQlUUkFDRV9JUlFT X09OCQkJLyogVXNlciBtb2RlIHRyYWNlcyBhcyBJUlFzIG9uLiAqLwogCW1vdnEJUkJYKCVyc3Ap LCAlcmJ4CQkvKiBwdF9yZWdzLT5yYnggKi8KIAltb3ZxCVJCUCglcnNwKSwgJXJicAkJLyogcHRf cmVncy0+cmJwICovCiAJbW92cQlFRkxBR1MoJXJzcCksICVyMTEJLyogcHRfcmVncy0+ZmxhZ3Mg KGluIHIxMSkgKi8KQEAgLTM5Niw2ICszOTUsNSBAQCBFTlRSWShlbnRyeV9JTlQ4MF9jb21wYXQp CiAuTHN5c2NhbGxfMzJfZG9uZToKIAogCS8qIEdvIGJhY2sgdG8gdXNlciBtb2RlLiAqLwotCVRS QUNFX0lSUVNfT04KIAlqbXAJc3dhcGdzX3Jlc3RvcmVfcmVnc19hbmRfcmV0dXJuX3RvX3VzZXJt b2RlCiBFTkQoZW50cnlfSU5UODBfY29tcGF0KQo= --00000000000038b2b005959aa2c3--