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=-9.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 114E2C33CAF for ; Thu, 16 Jan 2020 18:23:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DD78820684 for ; Thu, 16 Jan 2020 18:23:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="L3u4XrNN" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2395475AbgAPSX1 (ORCPT ); Thu, 16 Jan 2020 13:23:27 -0500 Received: from mail-wm1-f66.google.com ([209.85.128.66]:39707 "EHLO mail-wm1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2392450AbgAPSX0 (ORCPT ); Thu, 16 Jan 2020 13:23:26 -0500 Received: by mail-wm1-f66.google.com with SMTP id 20so4847102wmj.4 for ; Thu, 16 Jan 2020 10:23:25 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=Fo5dGHfcTYvpzozVFBOXz3UkWraK5woc+oSC5HJiXcE=; b=L3u4XrNNAszKKjQv0ZkuLk392iUHP396dPTe1o7i4I4Rn70UToXpoIinLrf97bIgV/ 4ycDtsxqHT5eRK9I5QPcPP0MkHiJqiYFpSdIPOv8bdWw3QB99MSuyb7Vogr3wInAxyIm QZw9fi2qlK4UbS/pwPZxkyo2L/x58od5e5xRvuVSlGCjyWevwpnQ3oP/Bdk+pqvME6hF MoEhSpfIFzmhvLCoEAgrQbuSXbQVp462NQL01puaH4wPxBs1JRA7A8fOjHORJQko0h/X O4b4aTrtQ+lp7G6vibDjGNBvRez28ZRQTzcgLNhZFet9mzBfgd3+Pkys/KqvHa2GyeQS GRsg== 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; bh=Fo5dGHfcTYvpzozVFBOXz3UkWraK5woc+oSC5HJiXcE=; b=BwYDy1EpASL/eNzX4ooa8nSZ4cUwan8/deBjc24nvu4W0qyWVt+rvoc9UxZHQtwxZY X5TNYYQFdUtez030P15aMidwuYxRKKMLN0wGwir/f6i1VTuRJRUyo2NCC+BJlSMxYRE2 zgHkTgK3GjCQxarWEpU1xSRIHmSJIjk9h5q6nbQTtliA4E1zOY+ibNM8y6vdnm6zdkrg 1L9v8bmibY+CXkaJt1F17Cb0gNynNifD+lS+s85hLH3PSfvZpoZtoSgNEmfXaNClJmsq oxAgVlzmw9/cHPa5LRp6FB2PT/l6FP58rvBEzmlnnkZlrf1Y61yvxvOuNnVDQmkrVkQb Y63A== X-Gm-Message-State: APjAAAUYyU4EtvWdqzmOYb1ktZHX1Qrv2wizjYo7dG2hN1fQdTfXreK2 LVeh/01XOTV/HCCZUmMAOfFGxQ== X-Google-Smtp-Source: APXvYqyCzzb7myDBqaZc69hlCcYxwa+1kytjgGC2ZMeSwse/HZHd393PjH6eBsaFCSTiFqIQThSLpQ== X-Received: by 2002:a1c:7c18:: with SMTP id x24mr339057wmc.21.1579199004749; Thu, 16 Jan 2020 10:23:24 -0800 (PST) Received: from mai.imgcgcw.net ([2a01:e34:ed2f:f020:6c63:1b50:1156:7f0f]) by smtp.gmail.com with ESMTPSA id b137sm1087920wme.26.2020.01.16.10.23.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 16 Jan 2020 10:23:24 -0800 (PST) From: Daniel Lezcano To: tglx@linutronix.de Cc: linux-kernel@vger.kernel.org, Boqun Feng , linux-hyperv@vger.kernel.org, "K. Y. Srinivasan" , Haiyang Zhang , Stephen Hemminger , Sasha Levin Subject: [PATCH 05/17] clocksource/drivers/hyper-v: Reserve PAGE_SIZE space for tsc page Date: Thu, 16 Jan 2020 19:22:52 +0100 Message-Id: <20200116182304.4926-5-daniel.lezcano@linaro.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200116182304.4926-1-daniel.lezcano@linaro.org> References: <74bf7170-401f-2962-ea5a-1e21431a9349@linaro.org> <20200116182304.4926-1-daniel.lezcano@linaro.org> Sender: linux-hyperv-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org From: Boqun Feng Currently, the reserved size for a tsc page is 4K, which is enough for communicating with hypervisor. However, in the case where we want to export the tsc page to userspace (e.g. for vDSO to read the clocksource), the tsc page should be at least PAGE_SIZE, otherwise, when PAGE_SIZE is larger than 4K, extra kernel data will be mapped into userspace, which means leaking kernel information. Therefore reserve PAGE_SIZE space for tsc_pg as a preparation for the vDSO support of ARM64 in the future. Also, while at it, replace all reference to tsc_pg with hv_get_tsc_page() since it should be the only interface to access tsc page. Signed-off-by: Boqun Feng (Microsoft) Cc: linux-hyperv@vger.kernel.org Reviewed-by: Michael Kelley Signed-off-by: Daniel Lezcano Link: https://lore.kernel.org/r/20191126021723.4710-1-boqun.feng@gmail.com --- drivers/clocksource/hyperv_timer.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c index 1aec08e82b7a..12d75b50a317 100644 --- a/drivers/clocksource/hyperv_timer.c +++ b/drivers/clocksource/hyperv_timer.c @@ -307,17 +307,20 @@ EXPORT_SYMBOL_GPL(hv_stimer_global_cleanup); struct clocksource *hyperv_cs; EXPORT_SYMBOL_GPL(hyperv_cs); -static struct ms_hyperv_tsc_page tsc_pg __aligned(PAGE_SIZE); +static union { + struct ms_hyperv_tsc_page page; + u8 reserved[PAGE_SIZE]; +} tsc_pg __aligned(PAGE_SIZE); struct ms_hyperv_tsc_page *hv_get_tsc_page(void) { - return &tsc_pg; + return &tsc_pg.page; } EXPORT_SYMBOL_GPL(hv_get_tsc_page); static u64 notrace read_hv_clock_tsc(struct clocksource *arg) { - u64 current_tick = hv_read_tsc_page(&tsc_pg); + u64 current_tick = hv_read_tsc_page(hv_get_tsc_page()); if (current_tick == U64_MAX) hv_get_time_ref_count(current_tick); @@ -397,7 +400,7 @@ static bool __init hv_init_tsc_clocksource(void) return false; hyperv_cs = &hyperv_cs_tsc; - phys_addr = virt_to_phys(&tsc_pg); + phys_addr = virt_to_phys(hv_get_tsc_page()); /* * The Hyper-V TLFS specifies to preserve the value of reserved -- 2.17.1