From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 5F666DE058 for ; Tue, 14 Oct 2008 10:25:32 +1100 (EST) Subject: Re: [PATCH 1/2] powerpc: don't pass unused regs around in head_.*.S From: Benjamin Herrenschmidt To: Sebastian Andrzej Siewior In-Reply-To: <1223820494-7822-2-git-send-email-sebastian@breakpoint.cc> References: <1223820494-7822-1-git-send-email-sebastian@breakpoint.cc> <1223820494-7822-2-git-send-email-sebastian@breakpoint.cc> Content-Type: text/plain Date: Tue, 14 Oct 2008 10:25:12 +1100 Message-Id: <1223940312.8157.281.camel@pasglop> Mime-Version: 1.0 Cc: linuxppc-dev@ozlabs.org, Sebastian Andrzej Siewior Reply-To: benh@kernel.crashing.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Sun, 2008-10-12 at 16:08 +0200, Sebastian Andrzej Siewior wrote: > From: Sebastian Andrzej Siewior > > This looks like a relict from arch/ppc. machine_init() is accepting > only two parameters (dtb, phys) and is using only the first one. This isn't 100% correct actually... First, the base head_32.S (could be called head_6xx.S I suppose) supports a few more calling conventions such as the real OF one, with added support for initrd and cmdline in registers , and the BootX one. Then, calling convention for the other cases is slightly better defined than just having r3 contain a device-tree pointer. The physical address is an important part of it, the fact that r5 is NULL to differenciate from an OF entry too, and we're moving toward the full ePAPR definition. Cheers, Ben.