From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by mx.groups.io with SMTP id smtpd.web10.7670.1686920207337433165 for ; Fri, 16 Jun 2023 05:56:47 -0700 Authentication-Results: mx.groups.io; dkim=missing; spf=pass (domain: arm.com, ip: 217.140.110.172, mailfrom: sudeep.holla@arm.com) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id D71571FB; Fri, 16 Jun 2023 05:57:30 -0700 (PDT) Received: from bogus (unknown [10.57.96.87]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 2A3233F71E; Fri, 16 Jun 2023 05:56:45 -0700 (PDT) Date: Fri, 16 Jun 2023 13:56:42 +0100 From: "Sudeep Holla" To: Sami Mujawar Cc: devel@edk2.groups.io, ardb+tianocore@kernel.org, thomas.abraham@arm.com, Pierre.Gondois@arm.com, Matteo.Carlini@arm.com, Akanksha.Jain2@arm.com, Ben.Adderson@arm.com, Sibel.Allinson@arm.com, nd@arm.com Subject: Re: [PATCH edk2-platforms v1 1/1] Platform/Arm: Disable memmap platform timers for JunoR0 Message-ID: <20230616125642.tydl6mfhr7ga4rcd@bogus> References: <20230616124059.19524-1-sami.mujawar@arm.com> MIME-Version: 1.0 In-Reply-To: <20230616124059.19524-1-sami.mujawar@arm.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Fri, Jun 16, 2023 at 01:40:59PM +0100, Sami Mujawar wrote: > Juno includes a system-level wakeup timer which is an implementation > of the ARM Generic Timer architecture. > The CNTCTL frame contains some registers that are accessible using a > Non-Secure access. Juno R0 incorrectly limits these accesses to Secure > access only. This issue is documented in the Juno Errata > 832219: APB port security breaks SBSA compliance > https://developer.arm.com/documentation/epm008857/latest > > This results in a crash when the OS tries to access these registers. > Therefore, disable memory mapped platform timers for Juno R0. > > Cc: Ard Biesheuvel > Cc: Thomas Abraham > Cc: Sudeep Holla > Tested-by: Sudeep Holla (fixes the ACPI based Linux boot on Juno R0 platform) -- Regards, Sudeep