From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matt Fleming Subject: Re: [PATCH 0/6] Apple device properties Date: Mon, 15 Aug 2016 12:54:14 +0100 Message-ID: <20160815115414.GE30909@codeblueprint.co.uk> References: <20160804145710.GL3636@codeblueprint.co.uk> <20160809133816.GA6571@wunner.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-wm0-f51.google.com ([74.125.82.51]:36532 "EHLO mail-wm0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752984AbcHOLyR (ORCPT ); Mon, 15 Aug 2016 07:54:17 -0400 Received: by mail-wm0-f51.google.com with SMTP id q128so85731857wma.1 for ; Mon, 15 Aug 2016 04:54:16 -0700 (PDT) Content-Disposition: inline In-Reply-To: <20160809133816.GA6571@wunner.de> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Lukas Wunner Cc: linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, Andreas Noever , x86@kernel.org, linux-acpi@vger.kernel.org On Tue, 09 Aug, at 03:38:16PM, Lukas Wunner wrote: > @@ -208,7 +201,10 @@ struct efi_config { > __pure const struct efi_config *__efi_early(void); > > #define efi_call_early(f, ...) \ > - __efi_early()->call(__efi_early()->f, __VA_ARGS__); > + __efi_early()->call(__efi_early()->is64 ? \ > + ((efi_boot_services_64_t *)__efi_early()->boot_services)->f : \ > + ((efi_boot_services_32_t *)__efi_early()->boot_services)->f, \ > + __VA_ARGS__); > You cannot use pointers from the firmware directly in mixed mode because the kernel is compiled for 64-bits but the firmware is using 32-bit addresses, so dereferencing a pointer causes a 64-bit load. That's the reason we deconstruct the tables and copy the addresses from the last level - so we don't have to jump through multiple pointers.