tools/objtool/orc_gen.c

Source file repositories/reference/linux-study-clean/tools/objtool/orc_gen.c

File Facts

System
Linux kernel
Corpus path
tools/objtool/orc_gen.c
Extension
.c
Size
3496 bytes
Lines
151
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: implementation source
Status
source implementation candidate

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

struct orc_list_entry {
	struct list_head list;
	struct orc_entry orc;
	struct section *insn_sec;
	unsigned long insn_off;
};

static int orc_list_add(struct list_head *orc_list, struct orc_entry *orc,
			struct section *sec, unsigned long offset)
{
	struct orc_list_entry *entry = malloc(sizeof(*entry));

	if (!entry) {
		WARN("malloc failed");
		return -1;
	}

	entry->orc	= *orc;
	entry->insn_sec = sec;
	entry->insn_off = offset;

	list_add_tail(&entry->list, orc_list);
	return 0;
}

static unsigned long alt_group_len(struct alt_group *alt_group)
{
	return alt_group->last_insn->offset +
	       alt_group->last_insn->len -
	       alt_group->first_insn->offset;
}

int orc_create(struct objtool_file *file)
{
	struct section *sec, *orc_sec;
	unsigned int nr = 0, idx = 0;
	struct orc_list_entry *entry;
	struct list_head orc_list;

	struct orc_entry null = { .type = ORC_TYPE_UNDEFINED };

	/* Build a deduplicated list of ORC entries: */
	INIT_LIST_HEAD(&orc_list);
	for_each_sec(file->elf, sec) {
		struct orc_entry orc, prev_orc = {0};
		struct instruction *insn;
		bool empty = true;

		if (!sec->text)
			continue;

		sec_for_each_insn(file, sec, insn) {
			struct alt_group *alt_group = insn->alt_group;
			int i;

			if (!alt_group) {
				if (init_orc_entry(&orc, insn->cfi, insn))
					return -1;
				if (!memcmp(&prev_orc, &orc, sizeof(orc)))
					continue;
				if (orc_list_add(&orc_list, &orc, sec,
						 insn->offset))
					return -1;
				nr++;
				prev_orc = orc;
				empty = false;
				continue;
			}

			/*
			 * Alternatives can have different stack layout
			 * possibilities (but they shouldn't conflict).
			 * Instead of traversing the instructions, use the
			 * alt_group's flattened byte-offset-addressed CFI
			 * array.
			 */
			for (i = 0; i < alt_group_len(alt_group); i++) {
				struct cfi_state *cfi = alt_group->cfi[i];
				if (!cfi)
					continue;
				/* errors are reported on the original insn */
				if (init_orc_entry(&orc, cfi, insn))
					return -1;
				if (!memcmp(&prev_orc, &orc, sizeof(orc)))
					continue;
				if (orc_list_add(&orc_list, &orc, insn->sec,
						 insn->offset + i))
					return -1;
				nr++;
				prev_orc = orc;

Annotation

Implementation Notes