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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
*/
#include <stdlib.h>
#include <string.h>
#include <linux/objtool_types.h>
#include <asm/orc_types.h>
#include <objtool/check.h>
#include <objtool/orc.h>
#include <objtool/warn.h>
#include <objtool/endianness.h>
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, 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;
empty = false;
}
/* Skip to the end of the alt_group */
insn = alt_group->last_insn;
}
/* Add a section terminator */
if (!empty) {
orc_list_add(&orc_list, &null, sec, sec->sh.sh_size);
nr++;
}
}
if (!nr)
return 0;
/* Create .orc_unwind, .orc_unwind_ip and .rela.orc_unwind_ip sections: */
sec = find_section_by_name(file->elf, ".orc_unwind");
if (sec) {
WARN("file already has .orc_unwind section, skipping");
return -1;
}
orc_sec = elf_create_section(file->elf, ".orc_unwind",
sizeof(struct orc_entry), nr);
if (!orc_sec)
return -1;
sec = elf_create_section_pair(file->elf, ".orc_unwind_ip", sizeof(int), nr, nr);
if (!sec)
return -1;
/* Write ORC entries to sections: */
list_for_each_entry(entry, &orc_list, list) {
if (write_orc_entry(file->elf, orc_sec, sec, idx++,
entry->insn_sec, entry->insn_off,
&entry->orc))
return -1;
}
return 0;
}
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