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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 253E9C433FE for ; Tue, 26 Oct 2021 14:36:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 064C8611C8 for ; Tue, 26 Oct 2021 14:36:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236731AbhJZOie (ORCPT ); Tue, 26 Oct 2021 10:38:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56994 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236742AbhJZOiL (ORCPT ); Tue, 26 Oct 2021 10:38:11 -0400 Received: from mail-pj1-x102b.google.com (mail-pj1-x102b.google.com [IPv6:2607:f8b0:4864:20::102b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C8697C061745 for ; Tue, 26 Oct 2021 07:35:47 -0700 (PDT) Received: by mail-pj1-x102b.google.com with SMTP id np13so11087838pjb.4 for ; Tue, 26 Oct 2021 07:35:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=pltELxhXmO26iewvCcOTgyQSWeQg6Qg1MaNOQ4EmcHI=; b=p62cJMplNt9vpB2Ge9z79b02uymMY/II4Fo9lGpEum4zaH0OkajI1gSb/amFlXwe0h LgYIuIzFcjCzwwxvAFvh8cHYDGVxnMti5UQUuk/eodYCAD6dB4oXZj4gM81jt83A88P4 3jtHGXakWFGIbxC+ndc8eldhM01NhbudEpgvj8Xg11yYDw+7yzKOP7OzmAF9wB3HpKAW 450hO2cvCISeefbmVR50S/S9njXnl/PoB1DG9XsRLKT4h+opxXZ9bwdTSzYyMfTSKFI6 PJD1yQix/gLfDHinQevV9giSHWsm6qBO0Udcx9PeAhnLyfWZql0XZPUjZiBK7KQri4gn pSTA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=pltELxhXmO26iewvCcOTgyQSWeQg6Qg1MaNOQ4EmcHI=; b=RxOSTaCooq6PJ1YQppfyvq5twPdxtYpjKdSy5ZXP1+SucR5sjb3/nV/coJWo7n8VVz ssN2sVQB9VXCJeYqOJB2V09b1WoreXgqqdHwMzePSZR4J1u7W9WjyCPGYasy9WLeh1Ys HIDkLYyFosm2+rLDbmbhjjJ1nI7VX9fhommN2qRXwpoS1Dyrze3mcv3zUCc9dnDXLs9Q V1xhc5E/TGPzJn7ukXZEpxx+H4GPZttYdWAvIaJRZM0UkyKA76bzx1ergJzFHGQDJZXu 6pkv46COJKYGnHUqh2Pfgk3P2+fZHx7KjVVGIml2oHfDVYP742oPY+G965uWG3oJwWyC I/XQ== X-Gm-Message-State: AOAM531wKT1CYklbScqZKdYVA/xFUZcO90m/k8kYYGjIAsOFajg0OJS3 5wCtv6P+dWyjhWmE7cO2u1PHU71Fo8o= X-Google-Smtp-Source: ABdhPJznBsu0HdH5i0+BiQP5LORoBkZS5mdrpLjvljC2lVsRIQng3GMGMvoncDBrmrDjhvyQRaqKDg== X-Received: by 2002:a17:90b:3892:: with SMTP id mu18mr4445225pjb.102.1635258947280; Tue, 26 Oct 2021 07:35:47 -0700 (PDT) Received: from localhost ([47.88.5.130]) by smtp.gmail.com with ESMTPSA id c4sm13515758pfl.53.2021.10.26.07.35.45 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Tue, 26 Oct 2021 07:35:47 -0700 (PDT) From: Lai Jiangshan To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, Lai Jiangshan , Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" Subject: [PATCH V4 34/50] x86/entry: Add the C version get_percpu_base() Date: Tue, 26 Oct 2021 22:34:20 +0800 Message-Id: <20211026143436.19071-9-jiangshanlai@gmail.com> X-Mailer: git-send-email 2.19.1.6.gb485710b In-Reply-To: <20211026141420.17138-1-jiangshanlai@gmail.com> References: <20211026141420.17138-1-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/entry64.c | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) diff --git a/arch/x86/entry/entry64.c b/arch/x86/entry/entry64.c index 446d91d7b376..8f3a9f2d9c6a 100644 --- a/arch/x86/entry/entry64.c +++ b/arch/x86/entry/entry64.c @@ -187,3 +187,39 @@ struct pt_regs *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 -- 2.19.1.6.gb485710b