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objtool: Add elf_create_reloc() helper
We have 4 instances of adding a relocation. Create a common helper to avoid growing even more. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Link: https://lkml.kernel.org/r/20210326151259.817438847@infradead.org
This commit is contained in:
Peter Zijlstra
Ingo Molnar
parent
3a647607b5
commit
ef47cc01cb
@ -433,8 +433,7 @@ reachable:
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static int create_static_call_sections(struct objtool_file *file)
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{
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struct section *sec, *reloc_sec;
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struct reloc *reloc;
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struct section *sec;
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struct static_call_site *site;
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struct instruction *insn;
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struct symbol *key_sym;
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@ -460,8 +459,7 @@ static int create_static_call_sections(struct objtool_file *file)
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if (!sec)
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return -1;
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reloc_sec = elf_create_reloc_section(file->elf, sec, SHT_RELA);
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if (!reloc_sec)
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if (!elf_create_reloc_section(file->elf, sec, SHT_RELA))
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return -1;
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idx = 0;
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@ -471,25 +469,11 @@ static int create_static_call_sections(struct objtool_file *file)
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memset(site, 0, sizeof(struct static_call_site));
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/* populate reloc for 'addr' */
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reloc = malloc(sizeof(*reloc));
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if (!reloc) {
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perror("malloc");
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if (elf_add_reloc_to_insn(file->elf, sec,
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idx * sizeof(struct static_call_site),
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R_X86_64_PC32,
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insn->sec, insn->offset))
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return -1;
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}
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memset(reloc, 0, sizeof(*reloc));
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insn_to_reloc_sym_addend(insn->sec, insn->offset, reloc);
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if (!reloc->sym) {
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WARN_FUNC("static call tramp: missing containing symbol",
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insn->sec, insn->offset);
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return -1;
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}
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reloc->type = R_X86_64_PC32;
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reloc->offset = idx * sizeof(struct static_call_site);
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reloc->sec = reloc_sec;
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elf_add_reloc(file->elf, reloc);
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/* find key symbol */
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key_name = strdup(insn->call_dest->name);
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@ -526,18 +510,11 @@ static int create_static_call_sections(struct objtool_file *file)
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free(key_name);
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/* populate reloc for 'key' */
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reloc = malloc(sizeof(*reloc));
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if (!reloc) {
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perror("malloc");
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if (elf_add_reloc(file->elf, sec,
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idx * sizeof(struct static_call_site) + 4,
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R_X86_64_PC32, key_sym,
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is_sibling_call(insn) * STATIC_CALL_SITE_TAIL))
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return -1;
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}
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memset(reloc, 0, sizeof(*reloc));
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reloc->sym = key_sym;
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reloc->addend = is_sibling_call(insn) ? STATIC_CALL_SITE_TAIL : 0;
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reloc->type = R_X86_64_PC32;
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reloc->offset = idx * sizeof(struct static_call_site) + 4;
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reloc->sec = reloc_sec;
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elf_add_reloc(file->elf, reloc);
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idx++;
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}
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@ -547,8 +524,7 @@ static int create_static_call_sections(struct objtool_file *file)
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static int create_mcount_loc_sections(struct objtool_file *file)
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{
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struct section *sec, *reloc_sec;
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struct reloc *reloc;
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struct section *sec;
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unsigned long *loc;
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struct instruction *insn;
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int idx;
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@ -571,8 +547,7 @@ static int create_mcount_loc_sections(struct objtool_file *file)
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if (!sec)
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return -1;
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reloc_sec = elf_create_reloc_section(file->elf, sec, SHT_RELA);
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if (!reloc_sec)
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if (!elf_create_reloc_section(file->elf, sec, SHT_RELA))
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return -1;
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idx = 0;
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@ -581,32 +556,11 @@ static int create_mcount_loc_sections(struct objtool_file *file)
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loc = (unsigned long *)sec->data->d_buf + idx;
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memset(loc, 0, sizeof(unsigned long));
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reloc = malloc(sizeof(*reloc));
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if (!reloc) {
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perror("malloc");
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if (elf_add_reloc_to_insn(file->elf, sec,
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idx * sizeof(unsigned long),
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R_X86_64_64,
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insn->sec, insn->offset))
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return -1;
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}
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memset(reloc, 0, sizeof(*reloc));
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if (insn->sec->sym) {
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reloc->sym = insn->sec->sym;
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reloc->addend = insn->offset;
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} else {
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reloc->sym = find_symbol_containing(insn->sec, insn->offset);
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if (!reloc->sym) {
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WARN("missing symbol for insn at offset 0x%lx\n",
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insn->offset);
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return -1;
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}
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reloc->addend = insn->offset - reloc->sym->offset;
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}
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reloc->type = R_X86_64_64;
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reloc->offset = idx * sizeof(unsigned long);
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reloc->sec = reloc_sec;
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elf_add_reloc(file->elf, reloc);
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idx++;
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}
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@ -211,32 +211,6 @@ struct reloc *find_reloc_by_dest(const struct elf *elf, struct section *sec, uns
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return find_reloc_by_dest_range(elf, sec, offset, 1);
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}
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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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{
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if (sec->sym) {
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reloc->sym = sec->sym;
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reloc->addend = offset;
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return;
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}
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/*
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* The Clang assembler strips section symbols, so we have to reference
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* the function symbol instead:
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*/
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reloc->sym = find_symbol_containing(sec, offset);
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if (!reloc->sym) {
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/*
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* Hack alert. This happens when we need to reference the NOP
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* pad insn immediately after the function.
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*/
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reloc->sym = find_symbol_containing(sec, offset - 1);
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}
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if (reloc->sym)
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reloc->addend = offset - reloc->sym->offset;
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}
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static int read_sections(struct elf *elf)
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{
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Elf_Scn *s = NULL;
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@ -473,14 +447,66 @@ err:
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return -1;
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}
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void elf_add_reloc(struct elf *elf, struct reloc *reloc)
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int elf_add_reloc(struct elf *elf, struct section *sec, unsigned long offset,
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unsigned int type, struct symbol *sym, int addend)
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{
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struct section *sec = reloc->sec;
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struct reloc *reloc;
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list_add_tail(&reloc->list, &sec->reloc_list);
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reloc = malloc(sizeof(*reloc));
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if (!reloc) {
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perror("malloc");
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return -1;
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}
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memset(reloc, 0, sizeof(*reloc));
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reloc->sec = sec->reloc;
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reloc->offset = offset;
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reloc->type = type;
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reloc->sym = sym;
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reloc->addend = addend;
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list_add_tail(&reloc->list, &sec->reloc->reloc_list);
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elf_hash_add(elf->reloc_hash, &reloc->hash, reloc_hash(reloc));
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sec->changed = true;
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sec->reloc->changed = true;
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return 0;
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}
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int elf_add_reloc_to_insn(struct elf *elf, struct section *sec,
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unsigned long offset, unsigned int type,
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struct section *insn_sec, unsigned long insn_off)
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{
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struct symbol *sym;
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int addend;
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if (insn_sec->sym) {
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sym = insn_sec->sym;
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addend = insn_off;
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} else {
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/*
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* The Clang assembler strips section symbols, so we have to
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* reference the function symbol instead:
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*/
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sym = find_symbol_containing(insn_sec, insn_off);
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if (!sym) {
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/*
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* Hack alert. This happens when we need to reference
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* the NOP pad insn immediately after the function.
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*/
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sym = find_symbol_containing(insn_sec, insn_off - 1);
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}
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if (!sym) {
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WARN("can't find symbol containing %s+0x%lx", insn_sec->name, insn_off);
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return -1;
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}
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addend = insn_off - sym->offset;
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}
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return elf_add_reloc(elf, sec, offset, type, sym, addend);
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}
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static int read_rel_reloc(struct section *sec, int i, struct reloc *reloc, unsigned int *symndx)
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@ -123,7 +123,13 @@ static inline u32 reloc_hash(struct reloc *reloc)
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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_add_reloc(struct elf *elf, struct section *sec, unsigned long offset,
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unsigned int type, struct symbol *sym, int addend);
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int elf_add_reloc_to_insn(struct elf *elf, struct section *sec,
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unsigned long offset, unsigned int type,
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struct section *insn_sec, unsigned long insn_off);
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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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@ -140,8 +146,6 @@ struct reloc *find_reloc_by_dest(const struct elf *elf, struct section *sec, uns
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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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#define for_each_sec(file, sec) \
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list_for_each_entry(sec, &file->elf->sections, list)
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@ -82,12 +82,11 @@ static int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi)
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}
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static int write_orc_entry(struct elf *elf, struct section *orc_sec,
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struct section *ip_rsec, unsigned int idx,
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struct section *ip_sec, unsigned int idx,
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struct section *insn_sec, unsigned long insn_off,
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struct orc_entry *o)
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{
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struct orc_entry *orc;
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struct reloc *reloc;
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/* populate ORC data */
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orc = (struct orc_entry *)orc_sec->data->d_buf + idx;
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@ -96,25 +95,9 @@ static int write_orc_entry(struct elf *elf, struct section *orc_sec,
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orc->bp_offset = bswap_if_needed(orc->bp_offset);
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/* populate reloc for ip */
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reloc = malloc(sizeof(*reloc));
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if (!reloc) {
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perror("malloc");
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if (elf_add_reloc_to_insn(elf, ip_sec, idx * sizeof(int), R_X86_64_PC32,
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insn_sec, insn_off))
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return -1;
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}
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memset(reloc, 0, sizeof(*reloc));
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insn_to_reloc_sym_addend(insn_sec, insn_off, reloc);
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if (!reloc->sym) {
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WARN("missing symbol for insn at offset 0x%lx",
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insn_off);
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return -1;
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}
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reloc->type = R_X86_64_PC32;
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reloc->offset = idx * sizeof(int);
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reloc->sec = ip_rsec;
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elf_add_reloc(elf, reloc);
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return 0;
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}
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@ -153,7 +136,7 @@ static unsigned long alt_group_len(struct alt_group *alt_group)
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int orc_create(struct objtool_file *file)
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{
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struct section *sec, *ip_rsec, *orc_sec;
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struct section *sec, *orc_sec;
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unsigned int nr = 0, idx = 0;
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struct orc_list_entry *entry;
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struct list_head orc_list;
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@ -242,13 +225,12 @@ int orc_create(struct objtool_file *file)
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sec = elf_create_section(file->elf, ".orc_unwind_ip", 0, sizeof(int), nr);
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if (!sec)
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return -1;
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ip_rsec = elf_create_reloc_section(file->elf, sec, SHT_RELA);
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if (!ip_rsec)
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if (!elf_create_reloc_section(file->elf, sec, SHT_RELA))
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return -1;
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/* Write ORC entries to sections: */
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list_for_each_entry(entry, &orc_list, list) {
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if (write_orc_entry(file->elf, orc_sec, ip_rsec, idx++,
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if (write_orc_entry(file->elf, orc_sec, sec, idx++,
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entry->insn_sec, entry->insn_off,
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&entry->orc))
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return -1;
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