kernel-ark/include/linux/elf.h
Paul Burton 774c105ed8 binfmt_elf: allow arch code to examine PT_LOPROC ... PT_HIPROC headers
MIPS is introducing new variants of its O32 ABI which differ in their
handling of floating point, in order to enable a gradual transition
towards a world where mips32 binaries can take advantage of new hardware
features only available when configured for certain FP modes. In order
to do this ELF binaries are being augmented with a new section that
indicates, amongst other things, the FP mode requirements of the binary.
The presence & location of such a section is indicated by a program
header in the PT_LOPROC ... PT_HIPROC range.

In order to allow the MIPS architecture code to examine the program
header & section in question, pass all program headers in this range
to an architecture-specific arch_elf_pt_proc function. This function
may return an error if the header is deemed invalid or unsuitable for
the system, in which case that error will be returned from
load_elf_binary and upwards through the execve syscall.

A means is required for the architecture code to make a decision once
it is known that all such headers have been seen, but before it is too
late to return from an execve syscall. For this purpose the
arch_check_elf function is added, and called once, after all PT_LOPROC
to PT_HIPROC headers have been passed to arch_elf_pt_proc but before
the code which invoked execve has been lost. This enables the
architecture code to make a decision based upon all the headers present
in an ELF binary and its interpreter, as is required to forbid
conflicting FP ABI requirements between an ELF & its interpreter.

In order to allow data to be stored throughout the calls to the above
functions, struct arch_elf_state is introduced.

Finally a variant of the SET_PERSONALITY macro is introduced which
accepts a pointer to the struct arch_elf_state, allowing it to act
based upon state observed from the architecture specific program
headers.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7679/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2014-11-24 07:45:02 +01:00

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1.4 KiB
C

#ifndef _LINUX_ELF_H
#define _LINUX_ELF_H
#include <asm/elf.h>
#include <uapi/linux/elf.h>
#ifndef elf_read_implies_exec
/* Executables for which elf_read_implies_exec() returns TRUE will
have the READ_IMPLIES_EXEC personality flag set automatically.
Override in asm/elf.h as needed. */
# define elf_read_implies_exec(ex, have_pt_gnu_stack) 0
#endif
#ifndef SET_PERSONALITY
#define SET_PERSONALITY(ex) \
set_personality(PER_LINUX | (current->personality & (~PER_MASK)))
#endif
#ifndef SET_PERSONALITY2
#define SET_PERSONALITY2(ex, state) \
SET_PERSONALITY(ex)
#endif
#if ELF_CLASS == ELFCLASS32
extern Elf32_Dyn _DYNAMIC [];
#define elfhdr elf32_hdr
#define elf_phdr elf32_phdr
#define elf_shdr elf32_shdr
#define elf_note elf32_note
#define elf_addr_t Elf32_Off
#define Elf_Half Elf32_Half
#else
extern Elf64_Dyn _DYNAMIC [];
#define elfhdr elf64_hdr
#define elf_phdr elf64_phdr
#define elf_shdr elf64_shdr
#define elf_note elf64_note
#define elf_addr_t Elf64_Off
#define Elf_Half Elf64_Half
#endif
/* Optional callbacks to write extra ELF notes. */
struct file;
struct coredump_params;
#ifndef ARCH_HAVE_EXTRA_ELF_NOTES
static inline int elf_coredump_extra_notes_size(void) { return 0; }
static inline int elf_coredump_extra_notes_write(struct coredump_params *cprm) { return 0; }
#else
extern int elf_coredump_extra_notes_size(void);
extern int elf_coredump_extra_notes_write(struct coredump_params *cprm);
#endif
#endif /* _LINUX_ELF_H */