From: Peter Zijlstra peterz@infradead.org
commit ef47cc01cb4abcd760d8ac66b9361d6ade4d0846 upstream.
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 [bwh: Backported to 5.10: drop changes in create_mcount_loc_sections()] Signed-off-by: Ben Hutchings ben@decadent.org.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- tools/objtool/check.c | 43 +++++------------------- tools/objtool/elf.c | 86 +++++++++++++++++++++++++++++++----------------- tools/objtool/elf.h | 10 +++-- tools/objtool/orc_gen.c | 30 +++------------- 4 files changed, 79 insertions(+), 90 deletions(-)
--- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -433,8 +433,7 @@ reachable:
static int create_static_call_sections(struct objtool_file *file) { - struct section *sec, *reloc_sec; - struct reloc *reloc; + struct section *sec; struct static_call_site *site; struct instruction *insn; struct symbol *key_sym; @@ -460,8 +459,7 @@ static int create_static_call_sections(s if (!sec) return -1;
- reloc_sec = elf_create_reloc_section(file->elf, sec, SHT_RELA); - if (!reloc_sec) + if (!elf_create_reloc_section(file->elf, sec, SHT_RELA)) return -1;
idx = 0; @@ -471,25 +469,11 @@ static int create_static_call_sections(s memset(site, 0, sizeof(struct static_call_site));
/* populate reloc for 'addr' */ - reloc = malloc(sizeof(*reloc)); - - if (!reloc) { - perror("malloc"); + if (elf_add_reloc_to_insn(file->elf, sec, + idx * sizeof(struct static_call_site), + R_X86_64_PC32, + insn->sec, insn->offset)) return -1; - } - memset(reloc, 0, sizeof(*reloc)); - - insn_to_reloc_sym_addend(insn->sec, insn->offset, reloc); - if (!reloc->sym) { - WARN_FUNC("static call tramp: missing containing symbol", - insn->sec, insn->offset); - return -1; - } - - reloc->type = R_X86_64_PC32; - reloc->offset = idx * sizeof(struct static_call_site); - reloc->sec = reloc_sec; - elf_add_reloc(file->elf, reloc);
/* find key symbol */ key_name = strdup(insn->call_dest->name); @@ -526,18 +510,11 @@ static int create_static_call_sections(s free(key_name);
/* populate reloc for 'key' */ - reloc = malloc(sizeof(*reloc)); - if (!reloc) { - perror("malloc"); + if (elf_add_reloc(file->elf, sec, + idx * sizeof(struct static_call_site) + 4, + R_X86_64_PC32, key_sym, + is_sibling_call(insn) * STATIC_CALL_SITE_TAIL)) return -1; - } - memset(reloc, 0, sizeof(*reloc)); - reloc->sym = key_sym; - reloc->addend = is_sibling_call(insn) ? STATIC_CALL_SITE_TAIL : 0; - reloc->type = R_X86_64_PC32; - reloc->offset = idx * sizeof(struct static_call_site) + 4; - reloc->sec = reloc_sec; - elf_add_reloc(file->elf, reloc);
idx++; } --- a/tools/objtool/elf.c +++ b/tools/objtool/elf.c @@ -262,32 +262,6 @@ struct reloc *find_reloc_by_dest(const s return find_reloc_by_dest_range(elf, sec, offset, 1); }
-void insn_to_reloc_sym_addend(struct section *sec, unsigned long offset, - struct reloc *reloc) -{ - if (sec->sym) { - reloc->sym = sec->sym; - reloc->addend = offset; - return; - } - - /* - * The Clang assembler strips section symbols, so we have to reference - * the function symbol instead: - */ - reloc->sym = find_symbol_containing(sec, offset); - if (!reloc->sym) { - /* - * Hack alert. This happens when we need to reference the NOP - * pad insn immediately after the function. - */ - reloc->sym = find_symbol_containing(sec, offset - 1); - } - - if (reloc->sym) - reloc->addend = offset - reloc->sym->offset; -} - static int read_sections(struct elf *elf) { Elf_Scn *s = NULL; @@ -524,14 +498,66 @@ err: return -1; }
-void elf_add_reloc(struct elf *elf, struct reloc *reloc) +int elf_add_reloc(struct elf *elf, struct section *sec, unsigned long offset, + unsigned int type, struct symbol *sym, int addend) { - struct section *sec = reloc->sec; + struct reloc *reloc;
- list_add_tail(&reloc->list, &sec->reloc_list); + reloc = malloc(sizeof(*reloc)); + if (!reloc) { + perror("malloc"); + return -1; + } + memset(reloc, 0, sizeof(*reloc)); + + reloc->sec = sec->reloc; + reloc->offset = offset; + reloc->type = type; + reloc->sym = sym; + reloc->addend = addend; + + list_add_tail(&reloc->list, &sec->reloc->reloc_list); elf_hash_add(elf->reloc_hash, &reloc->hash, reloc_hash(reloc));
- sec->changed = true; + sec->reloc->changed = true; + + return 0; +} + +int elf_add_reloc_to_insn(struct elf *elf, struct section *sec, + unsigned long offset, unsigned int type, + struct section *insn_sec, unsigned long insn_off) +{ + struct symbol *sym; + int addend; + + if (insn_sec->sym) { + sym = insn_sec->sym; + addend = insn_off; + + } else { + /* + * The Clang assembler strips section symbols, so we have to + * reference the function symbol instead: + */ + sym = find_symbol_containing(insn_sec, insn_off); + if (!sym) { + /* + * Hack alert. This happens when we need to reference + * the NOP pad insn immediately after the function. + */ + sym = find_symbol_containing(insn_sec, insn_off - 1); + } + + if (!sym) { + WARN("can't find symbol containing %s+0x%lx", insn_sec->name, insn_off); + return -1; + } + + addend = insn_off - sym->offset; + } + + return elf_add_reloc(elf, sec, offset, type, sym, addend); }
static int read_rel_reloc(struct section *sec, int i, struct reloc *reloc, unsigned int *symndx) --- a/tools/objtool/elf.h +++ b/tools/objtool/elf.h @@ -123,7 +123,13 @@ static inline u32 reloc_hash(struct relo struct elf *elf_open_read(const char *name, int flags); struct section *elf_create_section(struct elf *elf, const char *name, unsigned int sh_flags, size_t entsize, int nr); struct section *elf_create_reloc_section(struct elf *elf, struct section *base, int reltype); -void elf_add_reloc(struct elf *elf, struct reloc *reloc); + +int elf_add_reloc(struct elf *elf, struct section *sec, unsigned long offset, + unsigned int type, struct symbol *sym, int addend); +int elf_add_reloc_to_insn(struct elf *elf, struct section *sec, + unsigned long offset, unsigned int type, + struct section *insn_sec, unsigned long insn_off); + int elf_write_insn(struct elf *elf, struct section *sec, unsigned long offset, unsigned int len, const char *insn); @@ -140,8 +146,6 @@ struct reloc *find_reloc_by_dest(const s struct reloc *find_reloc_by_dest_range(const struct elf *elf, struct section *sec, unsigned long offset, unsigned int len); struct symbol *find_func_containing(struct section *sec, unsigned long offset); -void insn_to_reloc_sym_addend(struct section *sec, unsigned long offset, - struct reloc *reloc);
#define for_each_sec(file, sec) \ list_for_each_entry(sec, &file->elf->sections, list) --- a/tools/objtool/orc_gen.c +++ b/tools/objtool/orc_gen.c @@ -81,37 +81,20 @@ static int init_orc_entry(struct orc_ent }
static int write_orc_entry(struct elf *elf, struct section *orc_sec, - struct section *ip_rsec, unsigned int idx, + struct section *ip_sec, unsigned int idx, struct section *insn_sec, unsigned long insn_off, struct orc_entry *o) { struct orc_entry *orc; - struct reloc *reloc;
/* populate ORC data */ orc = (struct orc_entry *)orc_sec->data->d_buf + idx; memcpy(orc, o, sizeof(*orc));
/* populate reloc for ip */ - reloc = malloc(sizeof(*reloc)); - if (!reloc) { - perror("malloc"); + if (elf_add_reloc_to_insn(elf, ip_sec, idx * sizeof(int), R_X86_64_PC32, + insn_sec, insn_off)) return -1; - } - memset(reloc, 0, sizeof(*reloc)); - - insn_to_reloc_sym_addend(insn_sec, insn_off, reloc); - if (!reloc->sym) { - WARN("missing symbol for insn at offset 0x%lx", - insn_off); - return -1; - } - - reloc->type = R_X86_64_PC32; - reloc->offset = idx * sizeof(int); - reloc->sec = ip_rsec; - - elf_add_reloc(elf, reloc);
return 0; } @@ -150,7 +133,7 @@ static unsigned long alt_group_len(struc
int orc_create(struct objtool_file *file) { - struct section *sec, *ip_rsec, *orc_sec; + struct section *sec, *orc_sec; unsigned int nr = 0, idx = 0; struct orc_list_entry *entry; struct list_head orc_list; @@ -239,13 +222,12 @@ int orc_create(struct objtool_file *file sec = elf_create_section(file->elf, ".orc_unwind_ip", 0, sizeof(int), nr); if (!sec) return -1; - ip_rsec = elf_create_reloc_section(file->elf, sec, SHT_RELA); - if (!ip_rsec) + if (!elf_create_reloc_section(file->elf, sec, SHT_RELA)) return -1;
/* Write ORC entries to sections: */ list_for_each_entry(entry, &orc_list, list) { - if (write_orc_entry(file->elf, orc_sec, ip_rsec, idx++, + if (write_orc_entry(file->elf, orc_sec, sec, idx++, entry->insn_sec, entry->insn_off, &entry->orc)) return -1;