Features/PPC64 as primary

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Make 64-bit the primary arch for 64-bit PowerPC hardware

Summary

Provide a means for Fedora on 64-bit PowerPC hardware to have 64-bit as the primary architecture, which would enable users to better exploit their 64-bit PowerPC hardware and avoid restrictions associated with 32-bit applications.

Owner

  • email: <maynardj@us.ibm.com>

Current status

  • Targeted release: Fedora 21
  • Last updated: (February 12, 2009)
  • Percentage of completion: XX%


Detailed Description

Currently, 32-bit ppc is the default architecture, whether Fedora is installed on 32-bit or 64-bit PowerPC hardware. This leads to difficulties with software development, integration and installation when trying to use 64-bit programs on 64-bit hardware. Making 64-bit the default arch on 64-bit hardware is the simplest way to resolve these issues. This change in primary arch should also be accompanied with changing the default target for the compiler to be 64-bit (i.e., '-m64').

Ideally, this change should not prevent ppc32 software developed on earlier Fedora releases from being executed on Fedora 11. In theory, that implies a full complement of 32-bit runtime libraries to be made available in separate 32-bit packages (the inverse of what is provided today on Fedora). In practice, a reasonable approach may be to focus on providing just a subset of 32-bit libraries -- i.e., the most commonly used libraries.

Benefit to Fedora

Users who install Fedora on 64-bit PowerPC hardware will have a much more natural and smooth experience between their software and hardware, leading to higher satisfaction.

Scope

The scope of this change request is system-wide. I believe that, currently, ppc32 and ppc64 packages are built in separate buildroots. What I believe needs to be done to support this feature is:

1) a pure ppc64 repo

2) support in anaconda to do the right installation

3) support in yum

4) support in the repo compose scripts to do the multilib stuff properly


How To Test

Special hardware: 64-bit PowerPC hardware is needed


1. Install the ppc64 build on a 64-bit PowerPC system, installing all base packages (i.e., the ppc64 packages).

2. Perform standard tests.

3. Ensure that C and C++ compilation of test programs results in 64-bit executables.

4. Install secondary arch packages (i.e., 32-bit ppc).

5. Ensure that C and C++ compilation using -m32 is successful.

6. Run some popular 32-bit applications (from previous Fedora releases) to verify good bi-arch support.

User Experience

Software developers who install Fedora on 64-bit PowerPC hardware will notice that they don't have to bend over backwards to get their software to build 64-bit. The default 64-bit execution environment will also be appreicated.

Dependencies

Since this request is a system-wide change to the build process for PowerPC, there are no known dependencies.

Contingency Plan

None necessary, revert to previous release behaviour.

Documentation

None

Release Notes

Users installing or upgrading to Fedora 11 on 64-bit PowerPC hardware should note that the primary architecture is now ppc64. Package installation will default to ppc64, and compilation of C/C++ source code using Fedora-supplied compilers will default to 64-bit.

Comments and Discussion