linux_dsm_epyc7002/include/linux/auxvec.h
Nathan Lynch 483fad1c3f 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>
2008-07-25 15:44:39 +10:00

40 lines
1.4 KiB
C

#ifndef _LINUX_AUXVEC_H
#define _LINUX_AUXVEC_H
#include <asm/auxvec.h>
/* Symbolic values for the entries in the auxiliary table
put on the initial stack */
#define AT_NULL 0 /* end of vector */
#define AT_IGNORE 1 /* entry should be ignored */
#define AT_EXECFD 2 /* file descriptor of program */
#define AT_PHDR 3 /* program headers for program */
#define AT_PHENT 4 /* size of program header entry */
#define AT_PHNUM 5 /* number of program headers */
#define AT_PAGESZ 6 /* system page size */
#define AT_BASE 7 /* base address of interpreter */
#define AT_FLAGS 8 /* flags */
#define AT_ENTRY 9 /* entry point of program */
#define AT_NOTELF 10 /* program is not ELF */
#define AT_UID 11 /* real uid */
#define AT_EUID 12 /* effective uid */
#define AT_GID 13 /* real gid */
#define AT_EGID 14 /* effective gid */
#define AT_PLATFORM 15 /* string identifying CPU for optimizations */
#define AT_HWCAP 16 /* arch dependent hints at CPU capabilities */
#define AT_CLKTCK 17 /* frequency at which times() increments */
#define AT_SECURE 23 /* secure mode boolean */
#define AT_BASE_PLATFORM 24 /* string identifying real platform, may
* differ from AT_PLATFORM. */
#define AT_EXECFN 31 /* filename of program */
#ifdef __KERNEL__
#define AT_VECTOR_SIZE_BASE 18 /* NEW_AUX_ENT entries in auxiliary table */
/* number of "#define AT_.*" above, minus {AT_NULL, AT_IGNORE, AT_NOTELF} */
#endif
#endif /* _LINUX_AUXVEC_H */