]> pilppa.com Git - linux-2.6-omap-h63xx.git/commit
ELF loader support for auxvec base platform string
authorNathan Lynch <ntl@pobox.com>
Mon, 21 Jul 2008 18:48:46 +0000 (04:48 +1000)
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>
Fri, 25 Jul 2008 05:44:39 +0000 (15:44 +1000)
commit483fad1c3fa1060d7e6710e84a065ad514571739
tree98c2da31a58c71d1ae9c808bdf232cbbbe060550
parente9f76354ce83a20c7768ad37caa033f6506b4f96
ELF loader support for auxvec base platform string

Some IBM POWER-based platforms have the ability to run in a
mode which mostly appears to the OS as a different processor from the
actual hardware.  For example, a Power6 system may appear to be a
Power5+, which makes the AT_PLATFORM value "power5+".  This means that
programs are restricted to the ISA supported by Power5+;
Power6-specific instructions are treated as illegal.

However, some applications (virtual machines, optimized libraries) can
benefit from knowledge of the underlying CPU model.  A new aux vector
entry, AT_BASE_PLATFORM, will denote the actual hardware.  For
example, on a Power6 system in Power5+ compatibility mode, AT_PLATFORM
will be "power5+" and AT_BASE_PLATFORM will be "power6".  The idea is
that AT_PLATFORM indicates the instruction set supported, while
AT_BASE_PLATFORM indicates the underlying microarchitecture.

If the architecture has defined ELF_BASE_PLATFORM, copy that value to
the user stack in the same manner as ELF_PLATFORM.

Signed-off-by: Nathan Lynch <ntl@pobox.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
fs/binfmt_elf.c
include/linux/auxvec.h