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 9EB01C433F5 for ; Fri, 26 Nov 2021 10:26:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1377312AbhKZK3q (ORCPT ); Fri, 26 Nov 2021 05:29:46 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39052 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1376912AbhKZK1U (ORCPT ); Fri, 26 Nov 2021 05:27:20 -0500 Received: from mail-pj1-x1034.google.com (mail-pj1-x1034.google.com [IPv6:2607:f8b0:4864:20::1034]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DC95EC061370 for ; Fri, 26 Nov 2021 02:15:20 -0800 (PST) Received: by mail-pj1-x1034.google.com with SMTP id j6-20020a17090a588600b001a78a5ce46aso9623338pji.0 for ; Fri, 26 Nov 2021 02:15:20 -0800 (PST) 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=gqbv+71I1CWkSH2SnrMSgQz0SXEb2KPHeNxjLfYRhlI=; b=BoOlliByxwGG1c+qkJ/AQ9Ha0W8ZcYhM5XkQCpdAQFOYE+eG8h/Tucu2uprM3uzxt6 CfBXmPTk/6VTboUYa/6DTIuCZwzlx8EeUYfzdQ5CPi3R295UsR6qWtARA/gZXdZGSGot RLnBkpvgGY2inJGcyzS2e42HOaIP1+h8ThwEJ3jTd5Knh+D04C/lH8FwvbCOpXHxAmvf NwnTxoDmSAXpAP43+w8tHOxHCXp9aNP2HabOZF21kpeorYHYR0Ky50YvbyCw9QA46bNt qtPLYtl0fDLniA1j8UaHiFd0d7qnw++VXITccQ2xDsqEsq8HQAcoVYOsnTNCzVj2iA3F 61pQ== 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=gqbv+71I1CWkSH2SnrMSgQz0SXEb2KPHeNxjLfYRhlI=; b=0/1/QScfwRgFA+P1Kkksux+zkQebW5KFBjG5jj7AYyqwUuRiRTCDtMphz6w4LadE9D LKCqFoUjd5nasrcBCuB3EY+Sauj8yMCZLgh2Zu9HLN7Fxe726BZ0JWdJvAPNsKp4YgL6 J8hCMBdv0XS7KdBtHKZQdpTQae0WDmvaqC5SFIznjUuGyzvLgZ2oyO6jaMBGx9Mw51aI aY5lIK2EmQIRtpwC6M2S6vfwAt4H2U0CPqb1gGv2AMjCONTSFxK2TbJoiOAVR3fV1fnU K8h5MwrziWFYLQekCSIH48ZEllyPMWYPVQB/pjmds87MvBO+HTEdC7Ndxf1I91uZrJdY qb3g== X-Gm-Message-State: AOAM530Ag6hGeoRYVNl9wOjk8NAneMaGNLpCbBCuHrutcXsi7YlE+Nff sFNWvWTbrQMg0LRW1d+iL8db+6jx3Kw= X-Google-Smtp-Source: ABdhPJxXmTBYoufCBD6YF53cd1kfBGOQT2T83zCWCow8muwmi9PbM0mfkD0g7JlnTWlpRvb1e6AmDA== X-Received: by 2002:a17:903:1210:b0:143:a088:7932 with SMTP id l16-20020a170903121000b00143a0887932mr37599342plh.11.1637921720357; Fri, 26 Nov 2021 02:15:20 -0800 (PST) Received: from localhost ([47.251.3.230]) by smtp.gmail.com with ESMTPSA id h3sm7067554pfc.204.2021.11.26.02.15.19 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Fri, 26 Nov 2021 02:15:20 -0800 (PST) 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 V6 33/49] x86/entry: Add the C version get_percpu_base() Date: Fri, 26 Nov 2021 18:11:53 +0800 Message-Id: <20211126101209.8613-34-jiangshanlai@gmail.com> X-Mailer: git-send-email 2.19.1.6.gb485710b In-Reply-To: <20211126101209.8613-1-jiangshanlai@gmail.com> References: <20211126101209.8613-1-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 5f47221d8935..3ec145c38e9e 100644 --- a/arch/x86/entry/entry64.c +++ b/arch/x86/entry/entry64.c @@ -183,3 +183,39 @@ 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