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-rw-r--r--tools/objtool/orc_gen.c242
1 files changed, 242 insertions, 0 deletions
diff --git a/tools/objtool/orc_gen.c b/tools/objtool/orc_gen.c
new file mode 100644
index 000000000..812b33ed9
--- /dev/null
+++ b/tools/objtool/orc_gen.c
@@ -0,0 +1,242 @@
+// 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.h>
+#include <asm/orc_types.h>
+
+#include "check.h"
+#include "warn.h"
+
+static int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi,
+ struct instruction *insn)
+{
+ struct cfi_reg *bp = &cfi->regs[CFI_BP];
+
+ memset(orc, 0, sizeof(*orc));
+
+ if (!cfi) {
+ orc->end = 0;
+ orc->sp_reg = ORC_REG_UNDEFINED;
+ return 0;
+ }
+
+ orc->end = cfi->end;
+
+ if (cfi->cfa.base == CFI_UNDEFINED) {
+ orc->sp_reg = ORC_REG_UNDEFINED;
+ return 0;
+ }
+
+ switch (cfi->cfa.base) {
+ case CFI_SP:
+ orc->sp_reg = ORC_REG_SP;
+ break;
+ case CFI_SP_INDIRECT:
+ orc->sp_reg = ORC_REG_SP_INDIRECT;
+ break;
+ case CFI_BP:
+ orc->sp_reg = ORC_REG_BP;
+ break;
+ case CFI_BP_INDIRECT:
+ orc->sp_reg = ORC_REG_BP_INDIRECT;
+ break;
+ case CFI_R10:
+ orc->sp_reg = ORC_REG_R10;
+ break;
+ case CFI_R13:
+ orc->sp_reg = ORC_REG_R13;
+ break;
+ case CFI_DI:
+ orc->sp_reg = ORC_REG_DI;
+ break;
+ case CFI_DX:
+ orc->sp_reg = ORC_REG_DX;
+ break;
+ default:
+ WARN_FUNC("unknown CFA base reg %d",
+ insn->sec, insn->offset, cfi->cfa.base);
+ return -1;
+ }
+
+ switch (bp->base) {
+ case CFI_UNDEFINED:
+ orc->bp_reg = ORC_REG_UNDEFINED;
+ break;
+ case CFI_CFA:
+ orc->bp_reg = ORC_REG_PREV_SP;
+ break;
+ case CFI_BP:
+ orc->bp_reg = ORC_REG_BP;
+ break;
+ default:
+ WARN_FUNC("unknown BP base reg %d",
+ insn->sec, insn->offset, bp->base);
+ return -1;
+ }
+
+ orc->sp_offset = cfi->cfa.offset;
+ orc->bp_offset = bp->offset;
+ orc->type = cfi->type;
+
+ return 0;
+}
+
+static int write_orc_entry(struct elf *elf, struct section *orc_sec,
+ struct section *ip_sec, unsigned int idx,
+ struct section *insn_sec, unsigned long insn_off,
+ struct orc_entry *o)
+{
+ struct orc_entry *orc;
+
+ /* populate ORC data */
+ orc = (struct orc_entry *)orc_sec->data->d_buf + idx;
+ memcpy(orc, o, sizeof(*orc));
+
+ /* populate reloc for ip */
+ if (elf_add_reloc_to_insn(elf, ip_sec, idx * sizeof(int), R_X86_64_PC32,
+ insn_sec, insn_off))
+ return -1;
+
+ return 0;
+}
+
+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 = {
+ .sp_reg = ORC_REG_UNDEFINED,
+ .bp_reg = ORC_REG_UNDEFINED,
+ .type = UNWIND_HINT_TYPE_CALL,
+ };
+
+ /* 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->len);
+ 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", 0,
+ sizeof(struct orc_entry), nr);
+ if (!orc_sec)
+ return -1;
+
+ sec = elf_create_section(file->elf, ".orc_unwind_ip", 0, sizeof(int), 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;
+}