From nobody Tue Nov 4 00:30:53 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=linaro.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1529942630005104.30938868429587; Mon, 25 Jun 2018 09:03:50 -0700 (PDT) Received: from localhost ([::1]:47997 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fXTy1-0007VJ-9y for importer@patchew.org; Mon, 25 Jun 2018 12:03:49 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52755) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fXTuZ-0004oc-9S for qemu-devel@nongnu.org; Mon, 25 Jun 2018 12:00:16 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fXTuW-00050z-5Q for qemu-devel@nongnu.org; Mon, 25 Jun 2018 12:00:15 -0400 Received: from mail-wm0-x242.google.com ([2a00:1450:400c:c09::242]:52882) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1fXTuV-00050M-Uf for qemu-devel@nongnu.org; Mon, 25 Jun 2018 12:00:12 -0400 Received: by mail-wm0-x242.google.com with SMTP id p126-v6so9909152wmb.2 for ; Mon, 25 Jun 2018 09:00:11 -0700 (PDT) Received: from zen.linaro.local ([81.128.185.34]) by smtp.gmail.com with ESMTPSA id g11-v6sm15870933wrr.46.2018.06.25.09.00.09 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 25 Jun 2018 09:00:09 -0700 (PDT) Received: from zen.linaroharston (localhost [127.0.0.1]) by zen.linaro.local (Postfix) with ESMTP id 4A3FD3E0866; Mon, 25 Jun 2018 17:00:09 +0100 (BST) 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 :mime-version:content-transfer-encoding; bh=jw+vFO42AWQuky1xdpGzosmSyOqmsc+deFAWMnBM/sg=; b=VxzIpma3VPNKdSQ7OzVYCETDZg2WzgA20De3aWdWTDBV8SLXgfNAeWyk1aWLPimb7K +Q67LCxknAWiw1wIWC54GuoZKMcgka0r9bnw2UIXps/TAuw03m/rXsn9I5m8fj0URW2q jBYU81aUxzazgHsJO2yS/eE7akcVb1UYjfqSU= 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=jw+vFO42AWQuky1xdpGzosmSyOqmsc+deFAWMnBM/sg=; b=iw2ncsi3ip0pHXoFR/fAwqzRQAOwiQ3gef/+oRSRhAq/5d5jeyoP7BJO81c3zskg6e SkKIGvlIhc+dgXIYqKSjzsyQaG0vejkECk8G9zdWlFI3k/DW1DeAN63CWvY4LnLVgHXS 1JELHT0SplaugwJ321CfssFTj7jWTzF+1FNs6pjG+K0hxM/jfj+EjxZe48TN4nmnxHWv SPQesjkEYYYRot/lhP/gehgPkUDLW/+vLGFjXQURf67z+17KBuXzzI0FGRncaSAk0Dv9 SLglFoWUI0YVn3T1HWVAShsEbg4v3BrOXHfUwEf5B3Ip8tsn0C6psvIa6K/IIGKqSWFX tjGw== X-Gm-Message-State: APt69E1X0n/DjXVk3qFj7pqXfwjCna+Px5H5bHqIOqFyxHSqvujJnYq6 zVygGA5WBppGvVLMw0ksA4Gi7A== X-Google-Smtp-Source: AAOMgpeTCQRhB+WQMbXiw8QQI90XNwkAMsD/SjtlmZIZWYtnBBA6+UOl7w95fT2HK59LzKGq0wZHwA== X-Received: by 2002:a1c:c241:: with SMTP id s62-v6mr1530311wmf.146.1529942410567; Mon, 25 Jun 2018 09:00:10 -0700 (PDT) From: =?UTF-8?q?Alex=20Benn=C3=A9e?= To: peter.maydell@linaro.org Date: Mon, 25 Jun 2018 17:00:05 +0100 Message-Id: <20180625160009.17437-2-alex.bennee@linaro.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180625160009.17437-1-alex.bennee@linaro.org> References: <20180625160009.17437-1-alex.bennee@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2a00:1450:400c:c09::242 Subject: [Qemu-devel] [PATCH v3 1/5] target/arm: support reading of CNT[VCT|FRQ]_EL0 from user-space X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-arm@nongnu.org, =?UTF-8?q?Alex=20Benn=C3=A9e?= , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) X-ZohoMail: RDKM_2 RSF_0 Z_629925259 SPT_0 Since kernel commit a86bd139f2 (arm64: arch_timer: Enable CNTVCT_EL0 trap..) user-space has been able to read these system registers. As we can't use QEMUTimer's in linux-user mode we just directly call cpu_get_clock(). Signed-off-by: Alex Benn=C3=A9e Reviewed-by: Richard Henderson --- v2 - include CNTFRQ_EL0 for PL0_R only v3 - use NANOSECONDS_PER_SECOND / GTIMER_SCALE --- target/arm/helper.c | 27 ++++++++++++++++++++++++--- 1 file changed, 24 insertions(+), 3 deletions(-) diff --git a/target/arm/helper.c b/target/arm/helper.c index 1248d84e6f..6e6b1762e8 100644 --- a/target/arm/helper.c +++ b/target/arm/helper.c @@ -2166,11 +2166,32 @@ static const ARMCPRegInfo generic_timer_cp_reginfo[= ] =3D { }; =20 #else -/* In user-mode none of the generic timer registers are accessible, - * and their implementation depends on QEMU_CLOCK_VIRTUAL and qdev gpio ou= tputs, - * so instead just don't register any of them. + +/* In user-mode most of the generic timer registers are inaccessible + * however modern kernels (4.12+) allow access to cntvct_el0 */ + +static uint64_t gt_virt_cnt_read(CPUARMState *env, const ARMCPRegInfo *ri) +{ + /* Currently we have no support for QEMUTimer in linux-user so we + * can't call gt_get_countervalue(env), instead we directly + * call the lower level functions. + */ + return cpu_get_clock() / GTIMER_SCALE; +} + static const ARMCPRegInfo generic_timer_cp_reginfo[] =3D { + { .name =3D "CNTFRQ_EL0", .state =3D ARM_CP_STATE_AA64, + .opc0 =3D 3, .opc1 =3D 3, .crn =3D 14, .crm =3D 0, .opc2 =3D 0, + .type =3D ARM_CP_CONST, .access =3D PL0_R /* no PL1_RW in linux-user= */, + .fieldoffset =3D offsetof(CPUARMState, cp15.c14_cntfrq), + .resetvalue =3D NANOSECONDS_PER_SECOND / GTIMER_SCALE, + }, + { .name =3D "CNTVCT_EL0", .state =3D ARM_CP_STATE_AA64, + .opc0 =3D 3, .opc1 =3D 3, .crn =3D 14, .crm =3D 0, .opc2 =3D 2, + .access =3D PL0_R, .type =3D ARM_CP_NO_RAW | ARM_CP_IO, + .readfn =3D gt_virt_cnt_read, + }, REGINFO_SENTINEL }; =20 --=20 2.17.1