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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 484E1C38A2D for ; Tue, 25 Oct 2022 01:10:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231213AbiJYBKD (ORCPT ); Mon, 24 Oct 2022 21:10:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49282 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230512AbiJYBIZ (ORCPT ); Mon, 24 Oct 2022 21:08:25 -0400 Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6F79BD995D for ; Mon, 24 Oct 2022 17:17:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1666657061; x=1698193061; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=fhYTon+Hc+WcBW6ZSEbgkDupKrv70IXcyEjN02jeYOc=; b=dHPpgQ4BKmJY7y1Q45e5b+p3PyuvPie1RT5xF8dfXBx9m20axl6bO1VB bCKIqkEZZXANaYQl/P9vF8vEJfubyja9sMfmVxCqYvqitfLkTm547WScz 9/rKZ1jHnT5dTnGK1dqpaSIGmu+xW8HnJCXA/n895Xn21Oh/b9ioV6QVO R53WSO/LgMa7eSUkX91QPxoCGuijGdK4CtShCDhvZy1X1NDH6fIIBYuIp W18QSiooN+sT9pUwxMNsLnjLhNEVcN1JugYFB+Q4VuPstmFRorwMRQ02Y lYbeEjbc2gq7JsrPQ5et++lPvaE2RE/aiEP+0uNwLqDSRmjpMMOdpb95V Q==; X-IronPort-AV: E=McAfee;i="6500,9779,10510"; a="308644665" X-IronPort-AV: E=Sophos;i="5.95,210,1661842800"; d="scan'208";a="308644665" Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Oct 2022 17:17:39 -0700 X-IronPort-AV: E=McAfee;i="6500,9779,10510"; a="582587477" X-IronPort-AV: E=Sophos;i="5.95,210,1661842800"; d="scan'208";a="582587477" Received: from ghoyler-mobl.ger.corp.intel.com (HELO box.shutemov.name) ([10.249.39.118]) by orsmga003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Oct 2022 17:17:35 -0700 Received: by box.shutemov.name (Postfix, from userid 1000) id F05131095BD; Tue, 25 Oct 2022 03:17:25 +0300 (+03) From: "Kirill A. Shutemov" To: Dave Hansen , Andy Lutomirski , Peter Zijlstra Cc: x86@kernel.org, Kostya Serebryany , Andrey Ryabinin , Andrey Konovalov , Alexander Potapenko , Taras Madan , Dmitry Vyukov , "H . J . Lu" , Andi Kleen , Rick Edgecombe , Bharata B Rao , Jacob Pan , Ashok Raj , linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" Subject: [PATCHv11 08/16] x86/mm: Reduce untagged_addr() overhead until the first LAM user Date: Tue, 25 Oct 2022 03:17:14 +0300 Message-Id: <20221025001722.17466-9-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.38.0 In-Reply-To: <20221025001722.17466-1-kirill.shutemov@linux.intel.com> References: <20221025001722.17466-1-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Use static key to reduce untagged_addr() overhead. The key only gets enabled when the first process enables LAM. Signed-off-by: Kirill A. Shutemov --- arch/x86/include/asm/uaccess.h | 8 ++++++-- arch/x86/kernel/process_64.c | 4 ++++ 2 files changed, 10 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index c6062c07ccd2..820234f1f750 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -23,6 +23,8 @@ static inline bool pagefault_disabled(void); #endif #ifdef CONFIG_X86_64 +DECLARE_STATIC_KEY_FALSE(tagged_addr_key); + /* * Mask out tag bits from the address. * @@ -31,8 +33,10 @@ static inline bool pagefault_disabled(void); */ #define untagged_addr(mm, addr) ({ \ u64 __addr = (__force u64)(addr); \ - s64 sign = (s64)__addr >> 63; \ - __addr &= (mm)->context.untag_mask | sign; \ + if (static_branch_likely(&tagged_addr_key)) { \ + s64 sign = (s64)__addr >> 63; \ + __addr &= (mm)->context.untag_mask | sign; \ + } \ (__force __typeof__(addr))__addr; \ }) diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index a98536101447..9952e9f517ec 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -743,6 +743,9 @@ static long prctl_map_vdso(const struct vdso_image *image, unsigned long addr) } #endif +DEFINE_STATIC_KEY_FALSE(tagged_addr_key); +EXPORT_SYMBOL_GPL(tagged_addr_key); + static void enable_lam_func(void *mm) { struct mm_struct *loaded_mm = this_cpu_read(cpu_tlbstate.loaded_mm); @@ -792,6 +795,7 @@ static int prctl_enable_tagged_addr(struct mm_struct *mm, unsigned long nr_bits) } on_each_cpu_mask(mm_cpumask(mm), enable_lam_func, mm, true); + static_branch_enable(&tagged_addr_key); out: mmap_write_unlock(mm); return ret; -- 2.38.0