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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 81F4AC432BE for ; Tue, 31 Aug 2021 17:52:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 69B3160698 for ; Tue, 31 Aug 2021 17:52:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240754AbhHaRxc (ORCPT ); Tue, 31 Aug 2021 13:53:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56816 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240737AbhHaRxa (ORCPT ); Tue, 31 Aug 2021 13:53:30 -0400 Received: from mail-pg1-x529.google.com (mail-pg1-x529.google.com [IPv6:2607:f8b0:4864:20::529]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 85796C061575 for ; Tue, 31 Aug 2021 10:52:35 -0700 (PDT) Received: by mail-pg1-x529.google.com with SMTP id g184so17519717pgc.6 for ; Tue, 31 Aug 2021 10:52:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=4WMMfg+KI4gcEIMWO1vL86x46tSzmtJuTclikLoZhwI=; b=CrDx4RSlI6ybO1ODpILI7A/AzVVR9ipA6pLnOKiH4BwP0c3jEAE7VW/j/9ceQLLcR5 2NokslbHPVu/HTQ71tFiuC+7a0ZX0ylua32a1EC2Rt9eqW61Eh/+NjLgMHysbYhf4OdQ v4A9GRMqzlx9yZmE/TR9BZsFXVe0+ZgoXdsUVQjRMZzCp840RnTSXA9b5T2e3164TIXr ODQ3ArHrjz2++ke/VyPNfu0TFOQttj5VaNr2iWKbl6D1jZFBeGPb5YExnFEYLjZDG3g8 XtWhAtC5UBqna3cCNyYAqgwzZcnYRJXVS3LdiQDeddvbqen/OVoOCDdhjfiU96mNdVQL YKUw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=4WMMfg+KI4gcEIMWO1vL86x46tSzmtJuTclikLoZhwI=; b=X7z8vPBQnvzVNd/8ZGxkAh7T32b8KjP6bL/4Thi3fPlhbg4pl6YV5RjJFXqag0culy v3WVIEiHAhGzoscpNBWtwlF9DZAXRSzFAr0UGCQkcY3UXy1Ccc+2GWNa0tQs/RLqdfnu Yvc8oeuGvaWHaSnRu4doV/TpRuVNQvG4HEF2oXx6/7v5qqR0fuFhY73RNZ1+5haGhFEm RZmaAvBzXog5/KLn3FP+Wxn7F+8BMUJ14hHx324zynspqxcHXigUzI/44BoSoBg/CS6G Q1Ey48yTt1Mu3/cbAVW+tMEv81zs5z13pwg1+py+WeG8O5PfDe4nJ5V9/UHIJXMu3NXZ erbw== X-Gm-Message-State: AOAM532JbAYsHxYE4a9pVSWRLhFIelPDl0O4cFLi4ndkTrnlg3Mv/yuU 5OFLLtY6abeoYZiEfpxbOw0E0Lm9pUA= X-Google-Smtp-Source: ABdhPJy3Hx9xhSiocoYYzzYcCfnMbvT6rmasLsSvKR1eO1lsZXmsT4EGJVG5adtMlyFCo6D/CCxN/A== X-Received: by 2002:a63:fd54:: with SMTP id m20mr27872151pgj.104.1630432354888; Tue, 31 Aug 2021 10:52:34 -0700 (PDT) Received: from localhost ([47.251.3.230]) by smtp.gmail.com with ESMTPSA id i24sm7615467pfo.13.2021.08.31.10.52.34 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Tue, 31 Aug 2021 10:52:34 -0700 (PDT) From: Lai Jiangshan To: linux-kernel@vger.kernel.org Cc: Lai Jiangshan , Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" Subject: [PATCH 20/24] x86/entry: Add the C version get_percpu_base() Date: Wed, 1 Sep 2021 01:50:21 +0800 Message-Id: <20210831175025.27570-21-jiangshanlai@gmail.com> X-Mailer: git-send-email 2.19.1.6.gb485710b In-Reply-To: <20210831175025.27570-1-jiangshanlai@gmail.com> References: <20210831175025.27570-1-jiangshanlai@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Lai Jiangshan It implements the C version of asm macro GET_PERCPU_BASE(). Not functional difference intended. Signed-off-by: Lai Jiangshan --- arch/x86/entry/traps.c | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) diff --git a/arch/x86/entry/traps.c b/arch/x86/entry/traps.c index e912bfbd2a61..9f4bc52410d0 100644 --- a/arch/x86/entry/traps.c +++ b/arch/x86/entry/traps.c @@ -945,6 +945,42 @@ struct pt_regs *do_error_entry(struct pt_regs *eregs) /* Enter from kernel, don't move pt_regs */ return eregs; } + +#ifdef CONFIG_SMP +/* + * CPU/node NR is loaded from the limit (size) field of a special segment + * descriptor entry in GDT. + * + * Do not use RDPID, because KVM loads guest's TSC_AUX on vm-entry and + * may not restore the host's value until the CPU returns to userspace. + * Thus the kernel would consume a guest's TSC_AUX if an NMI arrives + * while running KVM's run loop. + */ +static __always_inline unsigned int gdt_get_cpu(void) +{ + unsigned int p; + + asm ("lsl %[seg],%[p]": [p] "=a" (p): [seg] "r" (__CPUNODE_SEG)); + + return p & VDSO_CPUNODE_MASK; +} + +/* + * Fetch the per-CPU GSBASE value for this processor. + * + * We normally use %gs for accessing per-CPU data, but we are setting up + * %gs here and obviously can not use %gs itself to access per-CPU data. + */ +static __always_inline unsigned long get_percpu_base(void) +{ + return __per_cpu_offset[gdt_get_cpu()]; +} +#else +static __always_inline unsigned long get_percpu_base(void) +{ + return pcpu_unit_offsets; +} +#endif #endif static bool is_sysenter_singlestep(struct pt_regs *regs) -- 2.19.1.6.gb485710b