x86: compat_binfmt_elf

This adds fs/compat_binfmt_elf.c, a wrapper around fs/binfmt_elf.c for
32-bit ELF support on 64-bit kernels.  It can replace all the hand-rolled
versions of this that each 32/64 arch has, which are all about the same.

To use this, an arch's asm/elf.h has to define at least a few compat_*
macros that parallel the various macros that fs/binfmt_elf.c uses for
native support.

There is no attempt to deal with compat macros for the core dump format
support.  To use this file, the arch has to define compat_gregset_t for
linux/elfcore-compat.h and #define CORE_DUMP_USE_REGSET.  The 32-bit
compatible formats should come automatically from task_user_regset_view
called on a 32-bit task.

Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Roland McGrath 2008-01-30 13:31:46 +01:00 committed by Ingo Molnar
parent bae3f7c39d
commit 2f79e48ae2
1 changed files with 131 additions and 0 deletions

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fs/compat_binfmt_elf.c Normal file
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/*
* 32-bit compatibility support for ELF format executables and core dumps.
*
* Copyright (C) 2007 Red Hat, Inc. All rights reserved.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU General Public License v.2.
*
* Red Hat Author: Roland McGrath.
*
* This file is used in a 64-bit kernel that wants to support 32-bit ELF.
* asm/elf.h is responsible for defining the compat_* and COMPAT_* macros
* used below, with definitions appropriate for 32-bit ABI compatibility.
*
* We use macros to rename the ABI types and machine-dependent
* functions used in binfmt_elf.c to compat versions.
*/
#include <linux/elfcore-compat.h>
#include <linux/time.h>
/*
* Rename the basic ELF layout types to refer to the 32-bit class of files.
*/
#undef ELF_CLASS
#define ELF_CLASS ELFCLASS32
#undef elfhdr
#undef elf_phdr
#undef elf_note
#undef elf_addr_t
#define elfhdr elf32_hdr
#define elf_phdr elf32_phdr
#define elf_note elf32_note
#define elf_addr_t Elf32_Addr
/*
* The machine-dependent core note format types are defined in elfcore-compat.h,
* which requires asm/elf.h to define compat_elf_gregset_t et al.
*/
#define elf_prstatus compat_elf_prstatus
#define elf_prpsinfo compat_elf_prpsinfo
/*
* Compat version of cputime_to_compat_timeval, perhaps this
* should be an inline in <linux/compat.h>.
*/
static void cputime_to_compat_timeval(const cputime_t cputime,
struct compat_timeval *value)
{
struct timeval tv;
cputime_to_timeval(cputime, &tv);
value->tv_sec = tv.tv_sec;
value->tv_usec = tv.tv_usec;
}
#undef cputime_to_timeval
#define cputime_to_timeval cputime_to_compat_timeval
/*
* To use this file, asm/elf.h must define compat_elf_check_arch.
* The other following macros can be defined if the compat versions
* differ from the native ones, or omitted when they match.
*/
#undef ELF_ARCH
#undef elf_check_arch
#define elf_check_arch compat_elf_check_arch
#ifdef COMPAT_ELF_PLATFORM
#undef ELF_PLATFORM
#define ELF_PLATFORM COMPAT_ELF_PLATFORM
#endif
#ifdef COMPAT_ELF_HWCAP
#undef ELF_HWCAP
#define ELF_HWCAP COMPAT_ELF_HWCAP
#endif
#ifdef COMPAT_ARCH_DLINFO
#undef ARCH_DLINFO
#define ARCH_DLINFO COMPAT_ARCH_DLINFO
#endif
#ifdef COMPAT_ELF_ET_DYN_BASE
#undef ELF_ET_DYN_BASE
#define ELF_ET_DYN_BASE COMPAT_ELF_ET_DYN_BASE
#endif
#ifdef COMPAT_ELF_EXEC_PAGESIZE
#undef ELF_EXEC_PAGESIZE
#define ELF_EXEC_PAGESIZE COMPAT_ELF_EXEC_PAGESIZE
#endif
#ifdef COMPAT_ELF_PLAT_INIT
#undef ELF_PLAT_INIT
#define ELF_PLAT_INIT COMPAT_ELF_PLAT_INIT
#endif
#ifdef COMPAT_SET_PERSONALITY
#undef SET_PERSONALITY
#define SET_PERSONALITY COMPAT_SET_PERSONALITY
#endif
#ifdef compat_start_thread
#undef start_thread
#define start_thread compat_start_thread
#endif
#ifdef compat_arch_setup_additional_pages
#undef ARCH_HAS_SETUP_ADDITIONAL_PAGES
#define ARCH_HAS_SETUP_ADDITIONAL_PAGES 1
#undef arch_setup_additional_pages
#define arch_setup_additional_pages compat_arch_setup_additional_pages
#endif
/*
* Rename a few of the symbols that binfmt_elf.c will define.
* These are all local so the names don't really matter, but it
* might make some debugging less confusing not to duplicate them.
*/
#define elf_format compat_elf_format
#define init_elf_binfmt init_compat_elf_binfmt
#define exit_elf_binfmt exit_compat_elf_binfmt
/*
* We share all the actual code with the native (64-bit) version.
*/
#include "binfmt_elf.c"