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 4EE30C433EF for ; Wed, 10 Nov 2021 12:01:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 307BF61056 for ; Wed, 10 Nov 2021 12:01:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231944AbhKJMD5 (ORCPT ); Wed, 10 Nov 2021 07:03:57 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36064 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231527AbhKJMDs (ORCPT ); Wed, 10 Nov 2021 07:03:48 -0500 Received: from mail-pj1-x1035.google.com (mail-pj1-x1035.google.com [IPv6:2607:f8b0:4864:20::1035]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 73F8CC06120A for ; Wed, 10 Nov 2021 04:01:01 -0800 (PST) Received: by mail-pj1-x1035.google.com with SMTP id x7so1347049pjn.0 for ; Wed, 10 Nov 2021 04:01:01 -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=AFDI/IplOkU185eWk3iBfyruG2Tg+h8kj9XGHi+QygqsWi2WLozv5W0xthAjeYVq3L txemHFmuilEDiAhWJRBS0gipM0EpPEZW7Oo9NlxFgiQL/JKe6kM3l4GDJtiaQGDFj5LK kZWZkoYlJiwN5yPRPinC//lthAfQlJEkQcMlc8RqrFYlGVQCUbMkCsDEeIgsDnEOJbg+ oIwvcJEM6V3xcoS6+hGBL9h8Oim4OrFIsRIi1RO+XVL6oDr8mqFRQIZwd+xQwub7eokM 45DihsDi7275gO7vMtkCnUm8DZAqwXWEZc0udF6kiWA3iqw4EJXJ8S55OA5HsBL1eiJ0 kCdQ== 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=skCwo7+eplALLYFfCbqaspwTjgpHGZAaX/tZ6Gj6IzD4D6kVjlWbgGUohkLvLwh7r8 6EBhFlihJcE0u/SyRLV0jfQmtcKNDJrbeSQQWLwzrfsfex5iXkIm91MPqFC4evcJY6lY /u2EJPmhnlnFASlDVkBPLVAhgL02WBbTYPq7fE7Tnlqc3CHQR/BrTd8zcrh9ymWJifpN +54O8zVIWA9Ep8Z43e9RgHyKHjXNUFoSGrl6Ta77ZWqME0Rxym0EqD67VSHv5YAqH/Ra Vgr+p9VgOtW6v0qKZZuhDsbvenQLFTNM2iWPClq8g0x3AFnkA3Ng0+M4jD42Z5fCXwMD xZvg== X-Gm-Message-State: AOAM530s2QJTV1kkX95/EHlQk+F+Nb3tQkaSD0AjrxC9miWBVrt0nK7E YhUqQQcbPum9EdAcQ9XKgAVQEZNAfsg= X-Google-Smtp-Source: ABdhPJx4BeeFk0FKpaRmmhjiDSPGKfq2FZJJX6PuKS7+8wqdCXn5gfkFStKBaifo4g+nFQ8pZR4ghw== X-Received: by 2002:a17:902:9694:b0:143:6f27:29ad with SMTP id n20-20020a170902969400b001436f2729admr13363157plp.46.1636545659668; Wed, 10 Nov 2021 04:00:59 -0800 (PST) Received: from localhost ([198.11.178.15]) by smtp.gmail.com with ESMTPSA id q18sm11078485pgm.24.2021.11.10.04.00.58 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 10 Nov 2021 04:00:59 -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 V5 34/50] x86/entry: Add the C version get_percpu_base() Date: Wed, 10 Nov 2021 19:57:20 +0800 Message-Id: <20211110115736.3776-35-jiangshanlai@gmail.com> X-Mailer: git-send-email 2.19.1.6.gb485710b In-Reply-To: <20211110115736.3776-1-jiangshanlai@gmail.com> References: <20211110115736.3776-1-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