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objtool: Don't set 'jump_dest' for sibling calls

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For most sibling calls, 'jump_dest' is NULL because objtool treats the
jump like a call and sets 'call_dest'.  But there are a few edge cases
where that's not true.  Make it consistent to avoid unexpected behavior.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/8737d6b9d1691831aed73375f444f0f42da3e2c9.1649718562.git.jpoimboe@redhat.com
This commit is contained in:
Josh Poimboeuf 2022-04-11 16:10:30 -07:00 committed by Peter Zijlstra
parent 02041b3225
commit 26ff604102
1 changed files with 22 additions and 13 deletions
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35
tools/objtool/check.c
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@ -1271,7 +1271,7 @@ static bool is_first_func_insn(struct objtool_file *file, struct instruction *in
*/
static int add_jump_destinations(struct objtool_file *file)
{
struct instruction *insn;
struct instruction *insn, *jump_dest;
struct reloc *reloc;
struct section *dest_sec;
unsigned long dest_off;
@ -1291,7 +1291,10 @@ static int add_jump_destinations(struct objtool_file *file)
add_retpoline_call(file, insn);
continue;
} else if (insn->func) {
/* internal or external sibling call (with reloc) */
/*
* External sibling call or internal sibling call with
* STT_FUNC reloc.
*/
add_call_dest(file, insn, reloc->sym, true);
continue;
} else if (reloc->sym->sec->idx) {
@ -1303,8 +1306,8 @@ static int add_jump_destinations(struct objtool_file *file)
continue;
}
insn->jump_dest = find_insn(file, dest_sec, dest_off);
if (!insn->jump_dest) {
jump_dest = find_insn(file, dest_sec, dest_off);
if (!jump_dest) {
/*
* This is a special case where an alt instruction
@ -1323,8 +1326,8 @@ static int add_jump_destinations(struct objtool_file *file)
/*
* Cross-function jump.
*/
if (insn->func && insn->jump_dest->func &&
insn->func != insn->jump_dest->func) {
if (insn->func && jump_dest->func &&
insn->func != jump_dest->func) {
/*
* For GCC 8+, create parent/child links for any cold
@ -1342,16 +1345,22 @@ static int add_jump_destinations(struct objtool_file *file)
* subfunction is through a jump table.
*/
if (!strstr(insn->func->name, ".cold") &&
strstr(insn->jump_dest->func->name, ".cold")) {
insn->func->cfunc = insn->jump_dest->func;
insn->jump_dest->func->pfunc = insn->func;
strstr(jump_dest->func->name, ".cold")) {
insn->func->cfunc = jump_dest->func;
jump_dest->func->pfunc = insn->func;
} else if (!same_function(insn, insn->jump_dest) &&
is_first_func_insn(file, insn->jump_dest)) {
/* internal sibling call (without reloc) */
add_call_dest(file, insn, insn->jump_dest->func, true);
} else if (!same_function(insn, jump_dest) &&
is_first_func_insn(file, jump_dest)) {
/*
* Internal sibling call without reloc or with
* STT_SECTION reloc.
*/
add_call_dest(file, insn, jump_dest->func, true);
continue;
}
}
insn->jump_dest = jump_dest;
}
return 0;