Practically speaking, MIPS has three useful ABIs:
* o32 is for 32-bits CPUs, or 64-bit CPUs running only a 32-bit subset
of the instruction set.
* n32 is for 64-bits CPUs only. It has 32-bits pointers and long
integers.
* n64 is for 64-bits CPUs only. It has 64-bits pointers and long
integers.
See http://www.linux-mips.org/wiki/MIPS_ABI_History and
http://www.linux-mips.org/wiki/WhatsWrongWithO32N32N64 for more
details.
So, this commit reworks the Buildroot MIPS support by:
* Add separate mips64/mips64el top-level architectures.
* Renaming the n32 ABI option to BR2_MIPS_NABI32, for consistency
with BR2_MIPS_OABI32.
* Renaming the n64 ABI option to BR2_MIPS_NABI64, for consistency
with BR2_MIPS_OABI32.
* Make the n32 and n64 ABI selections select the BR2_ARCH_IS_64,
since those ABIs are valid on 64-bits CPUs only.
* Removing the o64 ABI, which is practicaly never used.
* Removing the "none" ABI, which really doesn't make sense.
* Introduce the mips64 and mips64el architecture names when a 64-bits
MIPS ABI is choosen. This will fix build issue like
http://autobuild.buildroot.org/results/9b8c5ea86c953a89e85e7b67e9221de41773f652/build-end.log
where gmp was confused by the fact of having a 32 bits architecture
(detected by the mips- architecture part of the tuple) but 64 bits
integer size when compiling.
* Adjust the uclibc.mk logic to support the new mips64/mips64el
architecture names, and take into account the renaming of the ABI
options.
This has been build tested by generating Buildroot toolchains and
compiling a few packages for MIPS o32, MIPS n32 and MIPS n64.
This work is originally based on prior work done by Gustavo Zacarias.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
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