From d490aa21973fe66ec35ad825c19f88ac7f7abb27 Mon Sep 17 00:00:00 2001 From: Alexandre Chartre Date: Fri, 21 Nov 2025 10:53:23 +0100 Subject: [PATCH] objtool: Identify the different types of alternatives Alternative code, including jump table and exception table, is represented with the same struct alternative structure. But there is no obvious way to identify whether the struct represents alternative instructions, a jump table or an exception table. So add a type to struct alternative to clearly identify the type of alternative. Signed-off-by: Alexandre Chartre Signed-off-by: Peter Zijlstra (Intel) Acked-by: Josh Poimboeuf Link: https://patch.msgid.link/20251121095340.464045-14-alexandre.chartre@oracle.com --- tools/objtool/check.c | 13 ++++++++----- tools/objtool/include/objtool/check.h | 12 ++++++++++++ 2 files changed, 20 insertions(+), 5 deletions(-) diff --git a/tools/objtool/check.c b/tools/objtool/check.c index a02f8db75827f..93aaa4b5dce0e 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -27,11 +27,6 @@ #include #include -struct alternative { - struct alternative *next; - struct instruction *insn; -}; - static unsigned long nr_cfi, nr_cfi_reused, nr_cfi_cache; static struct cfi_init_state initial_func_cfi; @@ -1924,6 +1919,7 @@ static int add_special_section_alts(struct objtool_file *file) struct list_head special_alts; struct instruction *orig_insn, *new_insn; struct special_alt *special_alt, *tmp; + enum alternative_type alt_type; struct alternative *alt; if (special_get_alts(file->elf, &special_alts)) @@ -1959,9 +1955,15 @@ static int add_special_section_alts(struct objtool_file *file) if (handle_group_alt(file, special_alt, orig_insn, &new_insn)) return -1; + alt_type = ALT_TYPE_INSTRUCTIONS; + } else if (special_alt->jump_or_nop) { if (handle_jump_alt(file, special_alt, orig_insn, &new_insn)) return -1; + + alt_type = ALT_TYPE_JUMP_TABLE; + } else { + alt_type = ALT_TYPE_EX_TABLE; } alt = calloc(1, sizeof(*alt)); @@ -1972,6 +1974,7 @@ static int add_special_section_alts(struct objtool_file *file) alt->insn = new_insn; alt->next = orig_insn->alts; + alt->type = alt_type; orig_insn->alts = alt; list_del(&special_alt->list); diff --git a/tools/objtool/include/objtool/check.h b/tools/objtool/include/objtool/check.h index fde958683485f..cbf4af58e29b2 100644 --- a/tools/objtool/include/objtool/check.h +++ b/tools/objtool/include/objtool/check.h @@ -38,6 +38,18 @@ struct alt_group { bool ignore; }; +enum alternative_type { + ALT_TYPE_INSTRUCTIONS, + ALT_TYPE_JUMP_TABLE, + ALT_TYPE_EX_TABLE, +}; + +struct alternative { + struct alternative *next; + struct instruction *insn; + enum alternative_type type; +}; + #define INSN_CHUNK_BITS 8 #define INSN_CHUNK_SIZE (1 << INSN_CHUNK_BITS) #define INSN_CHUNK_MAX (INSN_CHUNK_SIZE - 1) -- 2.47.3