linux/tools/objtool/elf.h
Josh Poimboeuf 13810435b9 objtool: Support GCC 8's cold subfunctions
GCC 8 moves a lot of unlikely code out of line to "cold" subfunctions in
.text.unlikely.  Properly detect the new subfunctions and treat them as
extensions of the original functions.

This fixes a bunch of warnings like:

  kernel/cgroup/cgroup.o: warning: objtool: parse_cgroup_root_flags()+0x33: sibling call from callable instruction with modified stack frame
  kernel/cgroup/cgroup.o: warning: objtool: cgroup_addrm_files()+0x290: sibling call from callable instruction with modified stack frame
  kernel/cgroup/cgroup.o: warning: objtool: cgroup_apply_control_enable()+0x25b: sibling call from callable instruction with modified stack frame
  kernel/cgroup/cgroup.o: warning: objtool: rebind_subsystems()+0x325: sibling call from callable instruction with modified stack frame

Reported-and-tested-by: damian <damian.tometzki@icloud.com>
Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: David Laight <David.Laight@ACULAB.COM>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/0965e7fcfc5f31a276f0c7f298ff770c19b68706.1525923412.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-05-14 10:20:53 +02:00

107 lines
2.9 KiB
C

/*
* Copyright (C) 2015 Josh Poimboeuf <jpoimboe@redhat.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#ifndef _OBJTOOL_ELF_H
#define _OBJTOOL_ELF_H
#include <stdio.h>
#include <gelf.h>
#include <linux/list.h>
#include <linux/hashtable.h>
#ifdef LIBELF_USE_DEPRECATED
# define elf_getshdrnum elf_getshnum
# define elf_getshdrstrndx elf_getshstrndx
#endif
/*
* Fallback for systems without this "read, mmaping if possible" cmd.
*/
#ifndef ELF_C_READ_MMAP
#define ELF_C_READ_MMAP ELF_C_READ
#endif
struct section {
struct list_head list;
GElf_Shdr sh;
struct list_head symbol_list;
DECLARE_HASHTABLE(symbol_hash, 8);
struct list_head rela_list;
DECLARE_HASHTABLE(rela_hash, 16);
struct section *base, *rela;
struct symbol *sym;
Elf_Data *data;
char *name;
int idx;
unsigned int len;
bool changed, text;
};
struct symbol {
struct list_head list;
struct hlist_node hash;
GElf_Sym sym;
struct section *sec;
char *name;
unsigned int idx;
unsigned char bind, type;
unsigned long offset;
unsigned int len;
struct symbol *pfunc, *cfunc;
};
struct rela {
struct list_head list;
struct hlist_node hash;
GElf_Rela rela;
struct symbol *sym;
unsigned int type;
unsigned long offset;
int addend;
};
struct elf {
Elf *elf;
GElf_Ehdr ehdr;
int fd;
char *name;
struct list_head sections;
DECLARE_HASHTABLE(rela_hash, 16);
};
struct elf *elf_open(const char *name, int flags);
struct section *find_section_by_name(struct elf *elf, const char *name);
struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset);
struct symbol *find_symbol_by_name(struct elf *elf, const char *name);
struct symbol *find_symbol_containing(struct section *sec, unsigned long offset);
struct rela *find_rela_by_dest(struct section *sec, unsigned long offset);
struct rela *find_rela_by_dest_range(struct section *sec, unsigned long offset,
unsigned int len);
struct symbol *find_containing_func(struct section *sec, unsigned long offset);
struct section *elf_create_section(struct elf *elf, const char *name, size_t
entsize, int nr);
struct section *elf_create_rela_section(struct elf *elf, struct section *base);
int elf_rebuild_rela_section(struct section *sec);
int elf_write(struct elf *elf);
void elf_close(struct elf *elf);
#define for_each_sec(file, sec) \
list_for_each_entry(sec, &file->elf->sections, list)
#endif /* _OBJTOOL_ELF_H */