This is slightly stripped down from GENERIC64, as PowerMac G5 machines
are incapable of running in LE mode (so we can skip the Mac drivers.)
While technically POWER6 and POWER7 have the hardware capability of running
in LE mode, they have a tendency to trap excessively when a load/store is
misaligned. (an extremely common occurrence in LE code, and one of the main
reasons I consider BE to be superior, as it turns potential security issues
into immediately obvious mangled numbers.)
Additionally, there was no mechanism to control what endian interrupts
are delivered in, so supporting LE operation on POWER6 and POWER7 involves
some really dirty tricks in the interrupt vectors that I would rather
avoid.
IBM drew the line in the sand at POWER8 some time around 2013, embracing
full support for LE in the platform, and making a push across the board
for LE code to target POWER8 as a minimum requirement. As such, usage of
LE kernels on POWER6 and POWER7 is practically nil, despite it being
technically possible to do.
The so-called "TRUELE" feature bit which is the baseline requirement for
needed for PowerPC64LE was introduced in POWER8.
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