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44f6a7c075
The Clang assembler likes to strip section symbols, which means objtool
can't reference some text code by its section. This confuses objtool
greatly, causing it to seg fault.
The fix is similar to what was done before, for ORC reloc generation:
e81e072443 ("objtool: Support Clang non-section symbols in ORC generation")
Factor out that code into a common helper and use it for static call
reloc generation as well.
Reported-by: Arnd Bergmann <arnd@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Link: https://github.com/ClangBuiltLinux/linux/issues/1207
Link: https://lkml.kernel.org/r/ba6b6c0f0dd5acbba66e403955a967d9fdd1726a.1607983452.git.jpoimboe@redhat.com
151 lines
4.1 KiB
C
151 lines
4.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* Copyright (C) 2015 Josh Poimboeuf <jpoimboe@redhat.com>
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*/
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#ifndef _OBJTOOL_ELF_H
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#define _OBJTOOL_ELF_H
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#include <stdio.h>
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#include <gelf.h>
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#include <linux/list.h>
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#include <linux/hashtable.h>
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#include <linux/rbtree.h>
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#include <linux/jhash.h>
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#ifdef LIBELF_USE_DEPRECATED
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# define elf_getshdrnum elf_getshnum
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# define elf_getshdrstrndx elf_getshstrndx
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#endif
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/*
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* Fallback for systems without this "read, mmaping if possible" cmd.
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*/
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#ifndef ELF_C_READ_MMAP
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#define ELF_C_READ_MMAP ELF_C_READ
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#endif
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struct section {
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struct list_head list;
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struct hlist_node hash;
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struct hlist_node name_hash;
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GElf_Shdr sh;
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struct rb_root symbol_tree;
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struct list_head symbol_list;
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struct list_head reloc_list;
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struct section *base, *reloc;
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struct symbol *sym;
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Elf_Data *data;
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char *name;
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int idx;
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unsigned int len;
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bool changed, text, rodata, noinstr;
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};
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struct symbol {
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struct list_head list;
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struct rb_node node;
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struct hlist_node hash;
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struct hlist_node name_hash;
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GElf_Sym sym;
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struct section *sec;
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char *name;
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unsigned int idx;
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unsigned char bind, type;
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unsigned long offset;
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unsigned int len;
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struct symbol *pfunc, *cfunc, *alias;
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bool uaccess_safe;
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bool static_call_tramp;
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};
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struct reloc {
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struct list_head list;
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struct hlist_node hash;
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union {
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GElf_Rela rela;
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GElf_Rel rel;
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};
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struct section *sec;
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struct symbol *sym;
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unsigned long offset;
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unsigned int type;
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int addend;
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int idx;
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bool jump_table_start;
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};
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#define ELF_HASH_BITS 20
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struct elf {
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Elf *elf;
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GElf_Ehdr ehdr;
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int fd;
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bool changed;
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char *name;
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struct list_head sections;
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DECLARE_HASHTABLE(symbol_hash, ELF_HASH_BITS);
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DECLARE_HASHTABLE(symbol_name_hash, ELF_HASH_BITS);
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DECLARE_HASHTABLE(section_hash, ELF_HASH_BITS);
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DECLARE_HASHTABLE(section_name_hash, ELF_HASH_BITS);
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DECLARE_HASHTABLE(reloc_hash, ELF_HASH_BITS);
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};
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#define OFFSET_STRIDE_BITS 4
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#define OFFSET_STRIDE (1UL << OFFSET_STRIDE_BITS)
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#define OFFSET_STRIDE_MASK (~(OFFSET_STRIDE - 1))
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#define for_offset_range(_offset, _start, _end) \
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for (_offset = ((_start) & OFFSET_STRIDE_MASK); \
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_offset >= ((_start) & OFFSET_STRIDE_MASK) && \
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_offset <= ((_end) & OFFSET_STRIDE_MASK); \
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_offset += OFFSET_STRIDE)
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static inline u32 sec_offset_hash(struct section *sec, unsigned long offset)
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{
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u32 ol, oh, idx = sec->idx;
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offset &= OFFSET_STRIDE_MASK;
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ol = offset;
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oh = (offset >> 16) >> 16;
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__jhash_mix(ol, oh, idx);
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return ol;
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}
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static inline u32 reloc_hash(struct reloc *reloc)
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{
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return sec_offset_hash(reloc->sec, reloc->offset);
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}
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struct elf *elf_open_read(const char *name, int flags);
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struct section *elf_create_section(struct elf *elf, const char *name, unsigned int sh_flags, size_t entsize, int nr);
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struct section *elf_create_reloc_section(struct elf *elf, struct section *base, int reltype);
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void elf_add_reloc(struct elf *elf, struct reloc *reloc);
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int elf_write_insn(struct elf *elf, struct section *sec,
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unsigned long offset, unsigned int len,
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const char *insn);
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int elf_write_reloc(struct elf *elf, struct reloc *reloc);
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int elf_write(struct elf *elf);
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void elf_close(struct elf *elf);
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struct section *find_section_by_name(const struct elf *elf, const char *name);
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struct symbol *find_func_by_offset(struct section *sec, unsigned long offset);
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struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset);
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struct symbol *find_symbol_by_name(const struct elf *elf, const char *name);
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struct symbol *find_symbol_containing(const struct section *sec, unsigned long offset);
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struct reloc *find_reloc_by_dest(const struct elf *elf, struct section *sec, unsigned long offset);
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struct reloc *find_reloc_by_dest_range(const struct elf *elf, struct section *sec,
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unsigned long offset, unsigned int len);
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struct symbol *find_func_containing(struct section *sec, unsigned long offset);
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void insn_to_reloc_sym_addend(struct section *sec, unsigned long offset,
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struct reloc *reloc);
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int elf_rebuild_reloc_section(struct elf *elf, struct section *sec);
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#define for_each_sec(file, sec) \
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list_for_each_entry(sec, &file->elf->sections, list)
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#endif /* _OBJTOOL_ELF_H */
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