ARM hard-float linker path - consensus
A message that is not in the archive (sent off-list or not yet received): [email protected]
FYI this will impact us in coming time. If someone has questions please bring it up
---------- Forwarded message ----------
From: Steve McIntyre <[email protected]>
Date: Fri, Apr 13, 2012 at 10:37 AM
Subject: ARM hard-float linker path - consensus
To: [email protected]
Cc: [email protected], [email protected]
Hi folks,
As promised, here's minutes from the call we had this afternoon. Spoiler: the result we've agreed is
/lib/ld-linux-armhf.so.3
And here's a transcription of the minutes from
https://wiki.linaro.org/OfficeofCTO/HardFloat/LinkerPathCallApr2012
========================================
Meeting: 13th April 2012, 15:00 UTC
Agenda
------
* Debian/Ubuntu have so far built using /lib/arm-linux-gnueabihf/ld-linux.so.3
* Some other distros (Fedora, OpenSUSE) are still using /lib/ld-linux.so.3 option which matches the older soft-float ABI
* Some people are proposing /libhf/ld-linux.so.3 or /libhfp/ld-linux.so.3 (multilib)
* Some people proposed /lib/ld-arm-linux-gnueabihf.so.3 (similar to x86_64, libs still in /lib, from Michael Hope)
* What should we do as a community?
Present
-------
Name Affiliations
Steve McIntyre ARM, Debian, Linaro
Wookey ARM, Debian, Linaro
Richard Earnshaw ARM, gcc
Jeff Law Fedora, Red Hat, gcc, glibc
Jon Masters Fedora, Red Hat
Andrew Haley Fedora, Red Hat, gcc
Andreas Jaeger SUSE, openSUSE, glibc
Carlos O'Donnell Mentor, gcc
Steve Langasek Canonical, Ubuntu, Debian
Dann Frazier Canonical, Ubuntu, Debian
Adam Conrad Canonical, Ubuntu, Debian
Matthias Klose Canonical, Ubuntu, Debian
Mike Frysinger Gentoo
Dennis Gilmore Fedora, Red Hat
Discussion
----------
We started with a couple of questions up front to establish the grounds for discussion:
* We believed that decision makers were present for all the important parties, i.e. all the arm hard-float distros, plus toolchain developers. This meant that a decision taken at the meeting could be implemented without needing further arguments/negotiations.
* All the people present understood the importance of cross-distro binary compatibility, and they all wanted it. This led to agreement that we needed to agree on a standard path for the runtime linker for ARM hard-float Linux binaries.
Debian and Ubuntu had so far been using the "multi-arch" path of /lib/arm-linux-gnueabihf/ld-linux.so.3. Fedora and OpenSUSE were thus far using /lib/ld-linux.so.3, the same as the soft-float ABI. Others had proposed alternative paths such as /libhf/ld-linux.so.3 or /libhfp/ld-linux.so.3 (multilib) or /lib/ld-arm-linux-gnueabihf.so.3. Discussion showed that none of these were found to be universally acceptable.
Two parties were likely to be soon affected by an agreement here:
1. Ubuntu 12.04 (releasing with armhf in ~2 weeks)
Adam/Steve L agreed that all efforts would be put in to switch the compilers in Ubuntu to a new path before release. Default things like gcc would be correct, but less common tools might still be targetting the old path /lib/arm-linux-gnueabihf/ld-linux.so. at release. They could be fixed in the longer term and would not stop progress here.
2. Mentor (Codebench due for release in ~1 week)
Carlos mentioned this - Codebench has been using /lib/ld-linux.so.3 for hard-float binaries for some time and it was too late to change that for this upcoming release. Next release due in October. Suggested and accepted that this should be mentioned in release notes: if people want to use Codebench on some systems (Debian/Ubuntu and derivatives), they'll need to tweak their system setup. He may be able to do the linker change and rebuild in a point release in a few weeks.
It was briefly suggested that the soft-float linker should be renamed away from /lib/ld-linux.so.3 as well at this time, but that idea was quickly shot down.
Proposal #1: /lib/ld-armhf.so.3 (not generally liked)
Proposal #2: /lib/ld-linux-armhf.so.3 (not favourite, but considered an acceptable compromise by all)
No need to go any further.
Conclusion
----------
All the people in the meeting agreed: the new runtime linker path for ARM hard-float Linux binaries was to be
/lib/ld-linux-armhf.so.3
ACTION: People at the meeting to present this decision to their companies / communities and get the appropriate changes made.
Further discussion
------------------
General unhappiness with the mess that led to this meeting. Future planning needs to be better between the various groups for the next time we have a new CPU/ABI/whatever.
ACTION: Jon Masters to talk to the Linux Foundation about setting up a forum for such discussions.
In the meantime, strong consensus to use the [email protected] mailing list for any more conversations now we have people in contact.
ACTION: Steve McIntyre to write up the minutes and circulate. Include an updated linker path patch for gcc to match the decision made here.
More discussion about triplets and naming, but nothing came of it in the end. Distro folks have already decided what they're using and have patched various software to build appropriately. Richard wants to move gcc's config.guess to use arm-linux-gnueabihf; no strong objections to that.
Linker path patch for gcc
-------------------------
Adapted from earlier work by Dann Frazier <[email protected]> and Michael Hope <[email protected]>
2012-04-13 Steve McIntyre <[email protected]>
* config/arm/linux-eabi.h (GLIBC_DYNAMIC_LINKER_HARD_FLOAT): Define. (GLIBC_DYNAMIC_LINKER): Redefine to use the hard float path.
gcc/config/arm/linux-eabi.h +0 -0
@@ -62,7 +62,11 @@
/* Use ld-linux.so.3 so that it will be possible to run "classic" GNU/Linux binaries on an EABI system. */
#undef GLIBC_DYNAMIC_LINKER
-#define GLIBC_DYNAMIC_LINKER "/lib/ld-linux.so.3" +#define GLIBC_DYNAMIC_LINKER_SOFT_FLOAT "/lib/ld-linux.so.3" +#define GLIBC_DYNAMIC_LINKER_HARD_FLOAT "/lib/ld-linux-armhf.so.3" +#define GLIBC_DYNAMIC_LINKER \
+ "%{mfloat-abi=hard:" GLIBC_DYNAMIC_LINKER_HARD_FLOAT "} \
+ %{!mfloat-abi=hard:" GLIBC_DYNAMIC_LINKER_SOFT_FLOAT "}"
/* At this point, bpabi.h will have clobbered LINK_SPEC. We want to use the GNU/Linux version, not the generic BPABI version. */
Post-meeting on IRC
-------------------
Suggested that Richard should push the change into gcc trunk ASAP. Steve McIntyre agreed to work on that with Richard.
Also suggested that we want to get a patch into glibc too to change the installation path for ARM hard-float. Andrew agreed to push glibc upstream for that.
Cheers,
--
Steve McIntyre [email protected]
<http://www.linaro.org/> Linaro.org | Open source software for ARM SoCs
Quoted 2 lines · Khem Raj
FYI this will impact us in coming time. If someone has questions please bring it up
While it's a slightly unexpected outcome (/lib/ld-linux-armhf.so.3) it's still good to see some agreement here.
Do we want to make the necessary toolchain changes right away, or wait for them to propagate from upstream?
Signature · 1 line
Denys
Quoted 194 lines
---------- Forwarded message ----------
From: Steve McIntyre <[email protected]>
Date: Fri, Apr 13, 2012 at 10:37 AM
Subject: ARM hard-float linker path - consensus
To: [email protected]
Cc: [email protected], [email protected]Hi folks,
As promised, here's minutes from the call we had this afternoon. Spoiler: the result we've agreed is
/lib/ld-linux-armhf.so.3
And here's a transcription of the minutes from
https://wiki.linaro.org/OfficeofCTO/HardFloat/LinkerPathCallApr2012
========================================
Meeting: 13th April 2012, 15:00 UTC
Agenda
------* Debian/Ubuntu have so far built using
/lib/arm-linux-gnueabihf/ld-linux.so.3
* Some other distros (Fedora, OpenSUSE) are still using/lib/ld-linux.so.3option which matches the older soft-float ABI
* Some people are proposing /libhf/ld-linux.so.3 or /libhfp/ld-linux.so.3 (multilib)
* Some people proposed/lib/ld-arm-linux-gnueabihf.so.3(similar tox86_64, libs still in /lib, from Michael Hope)
* What should we do as a community?Present
-------Name Affiliations
Steve McIntyre ARM, Debian, Linaro
Wookey ARM, Debian, Linaro
Richard Earnshaw ARM, gcc
Jeff Law Fedora, Red Hat, gcc, glibc
Jon Masters Fedora, Red Hat
Andrew Haley Fedora, Red Hat, gcc
Andreas Jaeger SUSE, openSUSE, glibc
Carlos O'Donnell Mentor, gcc
Steve Langasek Canonical, Ubuntu, Debian
Dann Frazier Canonical, Ubuntu, Debian
Adam Conrad Canonical, Ubuntu, Debian
Matthias Klose Canonical, Ubuntu, Debian
Mike Frysinger Gentoo
Dennis Gilmore Fedora, Red HatDiscussion
----------We started with a couple of questions up front to establish the grounds for discussion:
* We believed that decision makers were present for all the important parties, i.e. all the arm hard-float distros, plus toolchain developers. This meant that a decision taken at the meeting could be implemented without needing further arguments/negotiations.
* All the people present understood the importance of cross-distro binary compatibility, and they all wanted it. This led to agreement that we needed to agree on a standard path for the runtime linker for ARM hard-float Linux binaries.
Debian and Ubuntu had so far been using the "multi-arch" path of
/lib/arm-linux-gnueabihf/ld-linux.so.3. Fedora and OpenSUSE were thus far using/lib/ld-linux.so.3, the same as the soft-float ABI. Others had proposed alternative paths such as /libhf/ld-linux.so.3 or /libhfp/ld-linux.so.3 (multilib) or/lib/ld-arm-linux-gnueabihf.so.3. Discussion showed that none of these were found to be universally acceptable.Two parties were likely to be soon affected by an agreement here:
1. Ubuntu 12.04 (releasing with armhf in ~2 weeks)
Adam/Steve L agreed that all efforts would be put in to switch the compilers in Ubuntu to a new path before release. Default things like gcc would be correct, but less common tools might still be targetting the old path
/lib/arm-linux-gnueabihf/ld-linux.so. at release. They could be fixed in the longer term and would not stop progress here.2. Mentor (Codebench due for release in ~1 week)
Carlos mentioned this - Codebench has been using
/lib/ld-linux.so.3for hard-float binaries for some time and it was too late to change that for this upcoming release. Next release due in October. Suggested and accepted that this should be mentioned in release notes: if people want to use Codebench on some systems (Debian/Ubuntu and derivatives), they'll need to tweak their system setup. He may be able to do the linker change and rebuild in a point release in a few weeks.It was briefly suggested that the soft-float linker should be renamed away from
/lib/ld-linux.so.3as well at this time, but that idea was quickly shot down.Proposal #1:
/lib/ld-armhf.so.3(not generally liked)Proposal #2:
/lib/ld-linux-armhf.so.3(not favourite, but considered an acceptable compromise by all)No need to go any further.
Conclusion
----------All the people in the meeting agreed: the new runtime linker path for ARM hard-float Linux binaries was to be
/lib/ld-linux-armhf.so.3ACTION: People at the meeting to present this decision to their companies / communities and get the appropriate changes made.
Further discussion
------------------General unhappiness with the mess that led to this meeting. Future planning needs to be better between the various groups for the next time we have a new CPU/ABI/whatever.
ACTION: Jon Masters to talk to the Linux Foundation about setting up a forum for such discussions.
In the meantime, strong consensus to use the [email protected] mailing list for any more conversations now we have people in contact.
ACTION: Steve McIntyre to write up the minutes and circulate. Include an updated linker path patch for gcc to match the decision made here.
More discussion about triplets and naming, but nothing came of it in the end. Distro folks have already decided what they're using and have patched various software to build appropriately. Richard wants to move gcc's config.guess to use arm-linux-gnueabihf; no strong objections to that.
Linker path patch for gcc
-------------------------Adapted from earlier work by Dann Frazier <[email protected]> and Michael Hope <[email protected]>
2012-04-13 Steve McIntyre <[email protected]>
*
config/arm/linux-eabi.h(GLIBC_DYNAMIC_LINKER_HARD_FLOAT): Define. (GLIBC_DYNAMIC_LINKER): Redefine to use the hard float path.gcc/config/arm/linux-eabi.h +0
-0@@ -62,7 +62,11 @@ /* Use ld-linux.so.3 so that it will be possible to run "classic"GNU/Linux binaries on an EABI system. */
#undef GLIBC_DYNAMIC_LINKERgcc/config/arm/linux-eabi.h +5
-1-#define GLIBC_DYNAMIC_LINKER "/lib/ld-linux.so.3" +#define GLIBC_DYNAMIC_LINKER_SOFT_FLOAT "/lib/ld-linux.so.3" +#define GLIBC_DYNAMIC_LINKER_HARD_FLOAT "/lib/ld-linux-armhf.so.3" +#define GLIBC_DYNAMIC_LINKER \ + "%{mfloat-abi=hard:" GLIBC_DYNAMIC_LINKER_HARD_FLOAT "} \ + %{!mfloat-abi=hard:" GLIBC_DYNAMIC_LINKER_SOFT_FLOAT "}"/* At this point,
bpabi.hwill have clobberedLINK_SPEC. We want to use the GNU/Linux version, not the generic BPABI version. */Post-meeting on IRC
-------------------Suggested that Richard should push the change into gcc trunk ASAP. Steve McIntyre agreed to work on that with Richard.
Also suggested that we want to get a patch into glibc too to change the installation path for ARM hard-float. Andrew agreed to push glibc upstream for that.
Cheers,
--
Steve McIntyre [email protected]
<http://www.linaro.org/> Linaro.org | Open source software for ARM SoCs_______________________________________________
Openembedded-core mailing list
[email protected]
http://lists.linuxtogo.org/cgi-bin/mailman/listinfo/openembedded-core
Quoted 9 lines · Denys Dmytriyenko
Quoted 2 lines · Khem Raj
FYI this will impact us in coming time. If someone has questions please bring it up
While it's a slightly unexpected outcome (
/lib/ld-linux-armhf.so.3) it's still good to see some agreement here.Do we want to make the necessary toolchain changes right away, or wait for them to propagate from upstream?
I plan to propose do it post 1.2 yocto release
Quoted 205 lines
--
DenysQuoted 190 lines
---------- Forwarded message ----------
From: Steve McIntyre <[email protected]>
Date: Fri, Apr 13, 2012 at 10:37 AM
Subject: ARM hard-float linker path - consensus
To: [email protected]
Cc: [email protected], [email protected]Hi folks,
As promised, here's minutes from the call we had this afternoon. Spoiler: the result we've agreed is
/lib/ld-linux-armhf.so.3
And here's a transcription of the minutes from
https://wiki.linaro.org/OfficeofCTO/HardFloat/LinkerPathCallApr2012
========================================
Meeting: 13th April 2012, 15:00 UTC
Agenda
------* Debian/Ubuntu have so far built using
/lib/arm-linux-gnueabihf/ld-linux.so.3
* Some other distros (Fedora, OpenSUSE) are still using/lib/ld-linux.so.3option which matches the older soft-float ABI
* Some people are proposing /libhf/ld-linux.so.3 or /libhfp/ld-linux.so.3 (multilib)
* Some people proposed/lib/ld-arm-linux-gnueabihf.so.3(similar tox86_64, libs still in /lib, from Michael Hope)
* What should we do as a community?Present
-------Name Affiliations
Steve McIntyre ARM, Debian, Linaro
Wookey ARM, Debian, Linaro
Richard Earnshaw ARM, gcc
Jeff Law Fedora, Red Hat, gcc, glibc
Jon Masters Fedora, Red Hat
Andrew Haley Fedora, Red Hat, gcc
Andreas Jaeger SUSE, openSUSE, glibc
Carlos O'Donnell Mentor, gcc
Steve Langasek Canonical, Ubuntu, Debian
Dann Frazier Canonical, Ubuntu, Debian
Adam Conrad Canonical, Ubuntu, Debian
Matthias Klose Canonical, Ubuntu, Debian
Mike Frysinger Gentoo
Dennis Gilmore Fedora, Red HatDiscussion
----------We started with a couple of questions up front to establish the grounds for discussion:
* We believed that decision makers were present for all the important parties, i.e. all the arm hard-float distros, plus toolchain developers. This meant that a decision taken at the meeting could be implemented without needing further arguments/negotiations.
* All the people present understood the importance of cross-distro binary compatibility, and they all wanted it. This led to agreement that we needed to agree on a standard path for the runtime linker for ARM hard-float Linux binaries.
Debian and Ubuntu had so far been using the "multi-arch" path of
/lib/arm-linux-gnueabihf/ld-linux.so.3. Fedora and OpenSUSE were thus far using/lib/ld-linux.so.3, the same as the soft-float ABI. Others had proposed alternative paths such as /libhf/ld-linux.so.3 or /libhfp/ld-linux.so.3 (multilib) or/lib/ld-arm-linux-gnueabihf.so.3. Discussion showed that none of these were found to be universally acceptable.Two parties were likely to be soon affected by an agreement here:
1. Ubuntu 12.04 (releasing with armhf in ~2 weeks)
Adam/Steve L agreed that all efforts would be put in to switch the compilers in Ubuntu to a new path before release. Default things like gcc would be correct, but less common tools might still be targetting the old path
/lib/arm-linux-gnueabihf/ld-linux.so. at release. They could be fixed in the longer term and would not stop progress here.2. Mentor (Codebench due for release in ~1 week)
Carlos mentioned this - Codebench has been using
/lib/ld-linux.so.3for hard-float binaries for some time and it was too late to change that for this upcoming release. Next release due in October. Suggested and accepted that this should be mentioned in release notes: if people want to use Codebench on some systems (Debian/Ubuntu and derivatives), they'll need to tweak their system setup. He may be able to do the linker change and rebuild in a point release in a few weeks.It was briefly suggested that the soft-float linker should be renamed away from
/lib/ld-linux.so.3as well at this time, but that idea was quickly shot down.Proposal #1:
/lib/ld-armhf.so.3(not generally liked)Proposal #2:
/lib/ld-linux-armhf.so.3(not favourite, but considered an acceptable compromise by all)No need to go any further.
Conclusion
----------All the people in the meeting agreed: the new runtime linker path for ARM hard-float Linux binaries was to be
/lib/ld-linux-armhf.so.3ACTION: People at the meeting to present this decision to their companies / communities and get the appropriate changes made.
Further discussion
------------------General unhappiness with the mess that led to this meeting. Future planning needs to be better between the various groups for the next time we have a new CPU/ABI/whatever.
ACTION: Jon Masters to talk to the Linux Foundation about setting up a forum for such discussions.
In the meantime, strong consensus to use the [email protected] mailing list for any more conversations now we have people in contact.
ACTION: Steve McIntyre to write up the minutes and circulate. Include an updated linker path patch for gcc to match the decision made here.
More discussion about triplets and naming, but nothing came of it in the end. Distro folks have already decided what they're using and have patched various software to build appropriately. Richard wants to move gcc's config.guess to use arm-linux-gnueabihf; no strong objections to that.
Linker path patch for gcc
-------------------------Adapted from earlier work by Dann Frazier <[email protected]> and Michael Hope <[email protected]>
2012-04-13 Steve McIntyre <[email protected]>
*
config/arm/linux-eabi.h(GLIBC_DYNAMIC_LINKER_HARD_FLOAT): Define. (GLIBC_DYNAMIC_LINKER): Redefine to use the hard float path.gcc/config/arm/linux-eabi.h +0
-0@@ -62,7 +62,11 @@ /* Use ld-linux.so.3 so that it will be possible to run "classic"GNU/Linux binaries on an EABI system. */
#undef GLIBC_DYNAMIC_LINKERgcc/config/arm/linux-eabi.h +5
-1-#define GLIBC_DYNAMIC_LINKER "/lib/ld-linux.so.3" +#define GLIBC_DYNAMIC_LINKER_SOFT_FLOAT "/lib/ld-linux.so.3" +#define GLIBC_DYNAMIC_LINKER_HARD_FLOAT "/lib/ld-linux-armhf.so.3" +#define GLIBC_DYNAMIC_LINKER \ + "%{mfloat-abi=hard:" GLIBC_DYNAMIC_LINKER_HARD_FLOAT "} \ + %{!mfloat-abi=hard:" GLIBC_DYNAMIC_LINKER_SOFT_FLOAT "}"/* At this point,
bpabi.hwill have clobberedLINK_SPEC. We want to use the GNU/Linux version, not the generic BPABI version. */Post-meeting on IRC
-------------------Suggested that Richard should push the change into gcc trunk ASAP. Steve McIntyre agreed to work on that with Richard.
Also suggested that we want to get a patch into glibc too to change the installation path for ARM hard-float. Andrew agreed to push glibc upstream for that.
Cheers,
--
Steve McIntyre [email protected]
<http://www.linaro.org/> Linaro.org | Open source software for ARM SoCsQuoted 4 lines
_______________________________________________
Openembedded-core mailing list
[email protected]
http://lists.linuxtogo.org/cgi-bin/mailman/listinfo/openembedded-core_______________________________________________
Openembedded-core mailing list
[email protected]
http://lists.linuxtogo.org/cgi-bin/mailman/listinfo/openembedded-core