From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752363Ab0IAHri (ORCPT ); Wed, 1 Sep 2010 03:47:38 -0400 Received: from mail-px0-f174.google.com ([209.85.212.174]:55414 "EHLO mail-px0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751205Ab0IAHrf (ORCPT ); Wed, 1 Sep 2010 03:47:35 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=ZyP3u2lCibQaM+fkE7V6sU4Ve43G4XQ7ryBCJPhn1QL6BkM2nQtNgUrGNaU2MMulMJ FphKUGKhzuzMF+QwrJZF9i98XVzXWfAi0NcmcE+Pwt89Ex6tuqJlkc6jfEemwtT7ItTs 94RL3Yt4CgJTR3n7/MCsyfrvQXlbsd9L1T4MA= Date: Wed, 1 Sep 2010 15:47:21 +0800 From: =?utf-8?Q?Am=C3=A9rico?= Wang To: Hendrik Brueckner Cc: mmarek@suse.cz, Sam Ravnborg , Michael Holzheu , tabbott@ksplice.com, vda.linux@googlemail.com, hpa@linux.intel.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, heiko.carstens@de.ibm.com, schwidefsky@de.ibm.com Subject: Re: [PATCH 2/2] initramfs: Fix initramfs size calculation Message-ID: <20100901074721.GA5671@cr0.nay.redhat.com> References: <20100831082307.064687027@linux.vnet.ibm.com> <20100831083844.043619334@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100831083844.043619334@linux.vnet.ibm.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 31, 2010 at 10:23:09AM +0200, Hendrik Brueckner wrote: >The size of a built-in initramfs is calculated in init/initramfs.c by >"__initramfs_end - __initramfs_start". Those symbols are defined in the >linker script include/asm-generic/vmlinux.lds.h: > >#define INIT_RAM_FS \ > . = ALIGN(PAGE_SIZE); \ > VMLINUX_SYMBOL(__initramfs_start) = .; \ > *(.init.ramfs) \ > VMLINUX_SYMBOL(__initramfs_end) = .; > >If the initramfs file has an odd number of bytes, the "__initramfs_end" >symbol points to an odd address, for example, the symbols in the System.map >might look like: > > 0000000000572000 T __initramfs_start > 00000000005bcd05 T __initramfs_end <-- odd address > >At least on s390 this causes a problem: > >Certain s390 instructions, especially instructions for loading addresses >(larl) or branch addresses must be on even addresses. >The compiler loads the symbol addresses with the "larl" instruction. This >instruction sets the last bit to 0 and, therefore, for odd size files, the >calculated size is one byte less than it should be: > > 0000000000540a9c : > 540a9c: eb cf f0 78 00 24 stmg %r12,%r15,120(%r15), > 540aa2: c0 10 00 01 8a af larl %r1,572000 <__initramfs_start> > 540aa8: c0 c0 00 03 e1 2e larl %r12,5bcd04 > (Instead of 5bcd05) > ... > 540abe: 1b c1 sr %r12,%r1 > >To fix the problem, this patch introduces the global variable >__initramfs_size, which is calculated in the "usr/initramfs_data.S" file. >The populate_rootfs() function can then use the start marker of the >.init.ramfs section and the value of __initramfs_size for loading the >initramfs. Because the start marker and size is sufficient, the >__initramfs_end symbol is no longer needed and is removed. > >Signed-off-by: Michael Holzheu >Signed-off-by: Hendrik Brueckner This patch looks good for me too, Reviewed-by: WANG Cong I think Michal will take this into kbuild tree. Thanks!