diff options
author | Nathan Lynch <ntl@pobox.com> | 2008-07-21 14:48:46 -0400 |
---|---|---|
committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2008-07-25 01:44:39 -0400 |
commit | 483fad1c3fa1060d7e6710e84a065ad514571739 (patch) | |
tree | 98c2da31a58c71d1ae9c808bdf232cbbbe060550 /include | |
parent | e9f76354ce83a20c7768ad37caa033f6506b4f96 (diff) |
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>
Diffstat (limited to 'include')
-rw-r--r-- | include/linux/auxvec.h | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/include/linux/auxvec.h b/include/linux/auxvec.h index 0da17d14fd1..d7afa9dd663 100644 --- a/include/linux/auxvec.h +++ b/include/linux/auxvec.h | |||
@@ -26,9 +26,13 @@ | |||
26 | 26 | ||
27 | #define AT_SECURE 23 /* secure mode boolean */ | 27 | #define AT_SECURE 23 /* secure mode boolean */ |
28 | 28 | ||
29 | #define AT_BASE_PLATFORM 24 /* string identifying real platform, may | ||
30 | * differ from AT_PLATFORM. */ | ||
31 | |||
29 | #define AT_EXECFN 31 /* filename of program */ | 32 | #define AT_EXECFN 31 /* filename of program */ |
33 | |||
30 | #ifdef __KERNEL__ | 34 | #ifdef __KERNEL__ |
31 | #define AT_VECTOR_SIZE_BASE 17 /* NEW_AUX_ENT entries in auxiliary table */ | 35 | #define AT_VECTOR_SIZE_BASE 18 /* NEW_AUX_ENT entries in auxiliary table */ |
32 | /* number of "#define AT_.*" above, minus {AT_NULL, AT_IGNORE, AT_NOTELF} */ | 36 | /* number of "#define AT_.*" above, minus {AT_NULL, AT_IGNORE, AT_NOTELF} */ |
33 | #endif | 37 | #endif |
34 | 38 | ||