From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Salter Subject: Re: c6x linker issue on linux-next-20160808 + some linker table work Date: Thu, 11 Aug 2016 13:14:34 -0400 Message-ID: <1470935674.3551.118.camel@redhat.com> References: <741c0f4d-bd9c-f28a-12d1-64bb483c6998@roeck-us.net> <1470762240.3551.42.camel@redhat.com> <20160809184023.GD3296@wotan.suse.de> <1470793827.3551.77.camel@redhat.com> <1470798247.3551.94.camel@redhat.com> <20160810213018.GS3296@wotan.suse.de> <1470870249.3551.100.camel@redhat.com> <20160811055627.GT3296@wotan.suse.de> <1470915162.3551.107.camel@redhat.com> <20160811155926.GX3296@wotan.suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit Return-path: Received: from mx1.redhat.com ([209.132.183.28]:53310 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751018AbcHKROh (ORCPT ); Thu, 11 Aug 2016 13:14:37 -0400 In-Reply-To: <20160811155926.GX3296@wotan.suse.de> Sender: linux-arch-owner@vger.kernel.org List-ID: To: "Luis R. Rodriguez" Cc: linux-arch , Aurelien Jacquiot , Josh Poimboeuf , "linux-kernel@vger.kernel.org" , Guenter Roeck , "H. Peter Anvin" On Thu, 2016-08-11 at 17:59 +0200, Luis R. Rodriguez wrote: > On Thu, Aug 11, 2016 at 07:32:42AM -0400, Mark Salter wrote: > > > > On Thu, 2016-08-11 at 07:56 +0200, Luis R. Rodriguez wrote: > > > > > > On Wed, Aug 10, 2016 at 07:04:09PM -0400, Mark Salter wrote: > > > > > > > > > > > > On Wed, 2016-08-10 at 23:30 +0200, Luis R. Rodriguez wrote: > > > > > > > > > > OK thanks I've found a clean solution minimal solution to this as follows. This now > > > > > builds fine. Is this a fine work around for now ? > > > > Almost. You also need: > > > > > > > > diff --git a/include/linux/tables.h b/include/linux/tables.h > > > > index a39ab03..3fa8d4d 100644 > > > > --- a/include/linux/tables.h > > > > +++ b/include/linux/tables.h > > > > @@ -325,7 +325,7 @@ > > > >               __attribute__((used,                                      \ > > > >                              weak,                                      \ > > > >                              __aligned__(LINUX_SECTION_ALIGNMENT(name)),\ > > > > -                            section(SECTION_TBL(SECTION_RODATA,        \ > > > > +                            section(SECTION_TBL(SECTION_TBL_RO,        \ > > > >                                                  name, level)))) > > > >   > > > >  /** > > > > > > > > Otherwise, start and end RO table markers end up in different sections. > > > I thought that was not needed as weak attributes already force it to go to > > > .const ? Anyway I've added this as well. Thanks! > > The section attribute forced both variables into .rodata but the weak > > attribute prevented accesses from using the SB-relative reloc. The > > non-weak variable is the one that led to the link error. > I ask as set_section_tbl_type() was not patched for instance, so firmware/Makefile > still uses SECTION_RODATA, and it compiles and links fine. Should that also be > using then SECTION_TBL_RO ? Or do we only need this for the C constructors ? > >   Luis Yuck. You need SECTION_TBL_RO and s/.rodata/.const/ in that Makefile. C6X doesn't support any of the devices with firmware, so I just added: fw-shipped-y += ti_3410.fw to firmware/Makefile for testing. Leaving in .rodata and SECTION_RODATA, I got: % readelf --syms vmlinux | grep -e _fw_ -e builtin_fw    8445: e01d4000     0 NOTYPE  LOCAL  DEFAULT    7 _fw_ti_3410_fw_bin   8446: e01d75c5     0 NOTYPE  LOCAL  DEFAULT    7 _fw_end   8447: e020a7cc     0 NOTYPE  LOCAL  DEFAULT    7 _fw_ti_3410_fw_name  11063: e023d688     0 OBJECT  GLOBAL DEFAULT   13 builtin_fw__end  15867: e023d688     0 OBJECT  WEAK   DEFAULT   13 builtin_fw >From the above addresses, the _fw symbols are in .rodata and the builtin_fw symbols are in .const. Changing the Makefile to use .rodata and SECTION_TBL_RO, I see:   8445: e0239688     0 NOTYPE  LOCAL  DEFAULT   13 _fw_ti_3410_fw_bin   8446: e023cc4d     0 NOTYPE  LOCAL  DEFAULT   13 _fw_end   8447: e023cc50     0 NOTYPE  LOCAL  DEFAULT   13 _fw_ti_3410_fw_name  11063: e0239688     0 OBJECT  GLOBAL DEFAULT   13 builtin_fw__end  15867: e0239688     0 OBJECT  WEAK   DEFAULT   13 builtin_fw which has everything in .const as it should be. But still builtin_fw and builtin_fw__end are at same address which seems wrong. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:53310 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751018AbcHKROh (ORCPT ); Thu, 11 Aug 2016 13:14:37 -0400 Message-ID: <1470935674.3551.118.camel@redhat.com> Subject: Re: c6x linker issue on linux-next-20160808 + some linker table work From: Mark Salter Date: Thu, 11 Aug 2016 13:14:34 -0400 In-Reply-To: <20160811155926.GX3296@wotan.suse.de> References: <741c0f4d-bd9c-f28a-12d1-64bb483c6998@roeck-us.net> <1470762240.3551.42.camel@redhat.com> <20160809184023.GD3296@wotan.suse.de> <1470793827.3551.77.camel@redhat.com> <1470798247.3551.94.camel@redhat.com> <20160810213018.GS3296@wotan.suse.de> <1470870249.3551.100.camel@redhat.com> <20160811055627.GT3296@wotan.suse.de> <1470915162.3551.107.camel@redhat.com> <20160811155926.GX3296@wotan.suse.de> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-arch-owner@vger.kernel.org List-ID: To: "Luis R. Rodriguez" Cc: linux-arch , Aurelien Jacquiot , Josh Poimboeuf , "linux-kernel@vger.kernel.org" , Guenter Roeck , "H. Peter Anvin" Message-ID: <20160811171434.y8jQKXnWsS-7JFogMfTNQ0EpTAKsv6CD3DBEQQLat8M@z> On Thu, 2016-08-11 at 17:59 +0200, Luis R. Rodriguez wrote: > On Thu, Aug 11, 2016 at 07:32:42AM -0400, Mark Salter wrote: > > > > On Thu, 2016-08-11 at 07:56 +0200, Luis R. Rodriguez wrote: > > > > > > On Wed, Aug 10, 2016 at 07:04:09PM -0400, Mark Salter wrote: > > > > > > > > > > > > On Wed, 2016-08-10 at 23:30 +0200, Luis R. Rodriguez wrote: > > > > > > > > > > OK thanks I've found a clean solution minimal solution to this as follows. This now > > > > > builds fine. Is this a fine work around for now ? > > > > Almost. You also need: > > > > > > > > diff --git a/include/linux/tables.h b/include/linux/tables.h > > > > index a39ab03..3fa8d4d 100644 > > > > --- a/include/linux/tables.h > > > > +++ b/include/linux/tables.h > > > > @@ -325,7 +325,7 @@ > > > >               __attribute__((used,                                      \ > > > >                              weak,                                      \ > > > >                              __aligned__(LINUX_SECTION_ALIGNMENT(name)),\ > > > > -                            section(SECTION_TBL(SECTION_RODATA,        \ > > > > +                            section(SECTION_TBL(SECTION_TBL_RO,        \ > > > >                                                  name, level)))) > > > >   > > > >  /** > > > > > > > > Otherwise, start and end RO table markers end up in different sections. > > > I thought that was not needed as weak attributes already force it to go to > > > .const ? Anyway I've added this as well. Thanks! > > The section attribute forced both variables into .rodata but the weak > > attribute prevented accesses from using the SB-relative reloc. The > > non-weak variable is the one that led to the link error. > I ask as set_section_tbl_type() was not patched for instance, so firmware/Makefile > still uses SECTION_RODATA, and it compiles and links fine. Should that also be > using then SECTION_TBL_RO ? Or do we only need this for the C constructors ? > >   Luis Yuck. You need SECTION_TBL_RO and s/.rodata/.const/ in that Makefile. C6X doesn't support any of the devices with firmware, so I just added: fw-shipped-y += ti_3410.fw to firmware/Makefile for testing. Leaving in .rodata and SECTION_RODATA, I got: % readelf --syms vmlinux | grep -e _fw_ -e builtin_fw    8445: e01d4000     0 NOTYPE  LOCAL  DEFAULT    7 _fw_ti_3410_fw_bin   8446: e01d75c5     0 NOTYPE  LOCAL  DEFAULT    7 _fw_end   8447: e020a7cc     0 NOTYPE  LOCAL  DEFAULT    7 _fw_ti_3410_fw_name  11063: e023d688     0 OBJECT  GLOBAL DEFAULT   13 builtin_fw__end  15867: e023d688     0 OBJECT  WEAK   DEFAULT   13 builtin_fw