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objtool: Disassemble jump table alternatives

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When using the --disas option, also disassemble jump tables.

Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://patch.msgid.link/20251121095340.464045-24-alexandre.chartre@oracle.com
This commit is contained in:
Alexandre Chartre
2025-11-21 10:53:33 +01:00
committed by Peter Zijlstra
parent 78df4590c5
commit 7e017720aa
1 changed files with 32 additions and 6 deletions
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38
tools/objtool/disas.c
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@@ -639,6 +639,34 @@ static int disas_alt_add_insn(struct disas_alt *dalt, int index, char *insn_str,
return 0;
}
static int disas_alt_jump(struct disas_alt *dalt)
{
struct instruction *orig_insn;
struct instruction *dest_insn;
char suffix[2] = { 0 };
char *str;
orig_insn = dalt->orig_insn;
dest_insn = dalt->alt->insn;
if (orig_insn->type == INSN_NOP) {
if (orig_insn->len == 5)
suffix[0] = 'q';
str = strfmt("jmp%-3s %lx <%s+0x%lx>", suffix,
dest_insn->offset, dest_insn->sym->name,
dest_insn->offset - dest_insn->sym->offset);
} else {
str = strfmt("nop%d", orig_insn->len);
}
if (!str)
return -1;
disas_alt_add_insn(dalt, 0, str, 0);
return 1;
}
/*
* Disassemble an exception table alternative.
*/
@@ -809,10 +837,7 @@ static void *disas_alt(struct disas_context *dctx,
goto done;
}
/*
* Only group alternatives and exception tables are
* supported at the moment.
*/
count = -1;
switch (dalt->alt->type) {
case ALT_TYPE_INSTRUCTIONS:
count = disas_alt_group(dctx, dalt);
@@ -820,8 +845,9 @@ static void *disas_alt(struct disas_context *dctx,
case ALT_TYPE_EX_TABLE:
count = disas_alt_extable(dalt);
break;
default:
count = 0;
case ALT_TYPE_JUMP_TABLE:
count = disas_alt_jump(dalt);
break;
}
if (count < 0) {
WARN("%s: failed to disassemble alternative %s",