summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
Diffstat
-rw-r--r--tools/objtool/elf.c170
-rw-r--r--tools/objtool/include/objtool/elf.h9
2 files changed, 165 insertions, 14 deletions
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 117a1b5915a1..8d01fc3b4f67 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -22,6 +22,8 @@
#include <objtool/warn.h>
#define ALIGN_UP(x, align_to) (((x) + ((align_to)-1)) & ~((align_to)-1))
+#define ALIGN_UP_POW2(x) (1U << ((8 * sizeof(x)) - __builtin_clz((x) - 1U)))
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
static inline u32 str_hash(const char *str)
{
@@ -899,10 +901,9 @@ elf_create_prefix_symbol(struct elf *elf, struct symbol *orig, size_t size)
offset, size);
}
-static struct reloc *elf_init_reloc(struct elf *elf, struct section *rsec,
- unsigned int reloc_idx,
- unsigned long offset, struct symbol *sym,
- s64 addend, unsigned int type)
+struct reloc *elf_init_reloc(struct elf *elf, struct section *rsec,
+ unsigned int reloc_idx, unsigned long offset,
+ struct symbol *sym, s64 addend, unsigned int type)
{
struct reloc *reloc, empty = { 0 };
@@ -1004,12 +1005,16 @@ static int read_relocs(struct elf *elf)
rsec->base->rsec = rsec;
- nr_reloc = 0;
+ /* nr_alloc_relocs=0: libelf owns d_buf */
+ rsec->nr_alloc_relocs = 0;
+
rsec->relocs = calloc(sec_num_entries(rsec), sizeof(*reloc));
if (!rsec->relocs) {
ERROR_GLIBC("calloc");
return -1;
}
+
+ nr_reloc = 0;
for (i = 0; i < sec_num_entries(rsec); i++) {
reloc = &rsec->relocs[i];
@@ -1258,8 +1263,116 @@ add:
return sec;
}
+static int elf_alloc_reloc(struct elf *elf, struct section *rsec)
+{
+ struct reloc *old_relocs, *old_relocs_end, *new_relocs;
+ unsigned int nr_relocs_old = sec_num_entries(rsec);
+ unsigned int nr_relocs_new = nr_relocs_old + 1;
+ unsigned long nr_alloc;
+ struct symbol *sym;
+
+ if (!rsec->data) {
+ rsec->data = elf_newdata(elf_getscn(elf->elf, rsec->idx));
+ if (!rsec->data) {
+ ERROR_ELF("elf_newdata");
+ return -1;
+ }
+
+ rsec->data->d_align = 1;
+ rsec->data->d_type = ELF_T_RELA;
+ rsec->data->d_buf = NULL;
+ }
+
+ rsec->data->d_size = nr_relocs_new * elf_rela_size(elf);
+ rsec->sh.sh_size = rsec->data->d_size;
+
+ nr_alloc = MAX(64, ALIGN_UP_POW2(nr_relocs_new));
+ if (nr_alloc <= rsec->nr_alloc_relocs)
+ return 0;
+
+ if (rsec->data->d_buf && !rsec->nr_alloc_relocs) {
+ void *orig_buf = rsec->data->d_buf;
+
+ /*
+ * The original d_buf is owned by libelf so it can't be
+ * realloced.
+ */
+ rsec->data->d_buf = malloc(nr_alloc * elf_rela_size(elf));
+ if (!rsec->data->d_buf) {
+ ERROR_GLIBC("malloc");
+ return -1;
+ }
+ memcpy(rsec->data->d_buf, orig_buf,
+ nr_relocs_old * elf_rela_size(elf));
+ } else {
+ rsec->data->d_buf = realloc(rsec->data->d_buf,
+ nr_alloc * elf_rela_size(elf));
+ if (!rsec->data->d_buf) {
+ ERROR_GLIBC("realloc");
+ return -1;
+ }
+ }
+
+ rsec->nr_alloc_relocs = nr_alloc;
+
+ old_relocs = rsec->relocs;
+ new_relocs = calloc(nr_alloc, sizeof(struct reloc));
+ if (!new_relocs) {
+ ERROR_GLIBC("calloc");
+ return -1;
+ }
+
+ if (!old_relocs)
+ goto done;
+
+ /*
+ * The struct reloc's address has changed. Update all the symbols and
+ * relocs which reference it.
+ */
+
+ old_relocs_end = &old_relocs[nr_relocs_old];
+ for_each_sym(elf, sym) {
+ struct reloc *reloc;
+
+ reloc = sym->relocs;
+ if (!reloc)
+ continue;
+
+ if (reloc >= old_relocs && reloc < old_relocs_end)
+ sym->relocs = &new_relocs[reloc - old_relocs];
+
+ while (1) {
+ struct reloc *next_reloc = sym_next_reloc(reloc);
+
+ if (!next_reloc)
+ break;
+
+ if (next_reloc >= old_relocs && next_reloc < old_relocs_end)
+ set_sym_next_reloc(reloc, &new_relocs[next_reloc - old_relocs]);
+
+ reloc = next_reloc;
+ }
+ }
+
+ memcpy(new_relocs, old_relocs, nr_relocs_old * sizeof(struct reloc));
+
+ for (int i = 0; i < nr_relocs_old; i++) {
+ struct reloc *old = &old_relocs[i];
+ struct reloc *new = &new_relocs[i];
+ u32 key = reloc_hash(old);
+
+ elf_hash_del(reloc, &old->hash, key);
+ elf_hash_add(reloc, &new->hash, key);
+ }
+
+ free(old_relocs);
+done:
+ rsec->relocs = new_relocs;
+ return 0;
+}
+
struct section *elf_create_rela_section(struct elf *elf, struct section *sec,
- unsigned int reloc_nr)
+ unsigned int nr_relocs)
{
struct section *rsec;
char *rsec_name;
@@ -1272,34 +1385,63 @@ struct section *elf_create_rela_section(struct elf *elf, struct section *sec,
strcpy(rsec_name, ".rela");
strcat(rsec_name, sec->name);
- rsec = elf_create_section(elf, rsec_name, reloc_nr * elf_rela_size(elf),
+ rsec = elf_create_section(elf, rsec_name, nr_relocs * elf_rela_size(elf),
elf_rela_size(elf), SHT_RELA, elf_addr_size(elf),
SHF_INFO_LINK);
free(rsec_name);
if (!rsec)
return NULL;
- rsec->sh.sh_link = find_section_by_name(elf, ".symtab")->idx;
- rsec->sh.sh_info = sec->idx;
-
- if (reloc_nr) {
+ if (nr_relocs) {
rsec->data->d_type = ELF_T_RELA;
- rsec->relocs = calloc(sec_num_entries(rsec), sizeof(struct reloc));
+
+ rsec->nr_alloc_relocs = nr_relocs;
+ rsec->relocs = calloc(nr_relocs, sizeof(struct reloc));
if (!rsec->relocs) {
ERROR_GLIBC("calloc");
return NULL;
}
}
+ rsec->sh.sh_link = find_section_by_name(elf, ".symtab")->idx;
+ rsec->sh.sh_info = sec->idx;
+
sec->rsec = rsec;
rsec->base = sec;
return rsec;
}
+struct reloc *elf_create_reloc(struct elf *elf, struct section *sec,
+ unsigned long offset,
+ struct symbol *sym, s64 addend,
+ unsigned int type)
+{
+ struct section *rsec = sec->rsec;
+
+ if (!rsec) {
+ rsec = elf_create_rela_section(elf, sec, 0);
+ if (!rsec)
+ return NULL;
+ }
+
+ if (find_reloc_by_dest(elf, sec, offset)) {
+ ERROR_FUNC(sec, offset, "duplicate reloc");
+ return NULL;
+ }
+
+ if (elf_alloc_reloc(elf, rsec))
+ return NULL;
+
+ mark_sec_changed(elf, rsec, true);
+
+ return elf_init_reloc(elf, rsec, sec_num_entries(rsec) - 1, offset, sym,
+ addend, type);
+}
+
struct section *elf_create_section_pair(struct elf *elf, const char *name,
size_t entsize, unsigned int nr,
- unsigned int reloc_nr)
+ unsigned int nr_relocs)
{
struct section *sec;
@@ -1308,7 +1450,7 @@ struct section *elf_create_section_pair(struct elf *elf, const char *name,
if (!sec)
return NULL;
- if (!elf_create_rela_section(elf, sec, reloc_nr))
+ if (!elf_create_rela_section(elf, sec, nr_relocs))
return NULL;
return sec;
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index 0d9aeefb6d12..999fd9369cf5 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -47,6 +47,7 @@ struct section {
int idx;
bool _changed, text, rodata, noinstr, init, truncate;
struct reloc *relocs;
+ unsigned long nr_alloc_relocs;
};
struct symbol {
@@ -140,6 +141,14 @@ void *elf_add_data(struct elf *elf, struct section *sec, const void *data,
unsigned int elf_add_string(struct elf *elf, struct section *strtab, const char *str);
+struct reloc *elf_create_reloc(struct elf *elf, struct section *sec,
+ unsigned long offset, struct symbol *sym,
+ s64 addend, unsigned int type);
+
+struct reloc *elf_init_reloc(struct elf *elf, struct section *rsec,
+ unsigned int reloc_idx, unsigned long offset,
+ struct symbol *sym, s64 addend, unsigned int type);
+
struct reloc *elf_init_reloc_text_sym(struct elf *elf, struct section *sec,
unsigned long offset,
unsigned int reloc_idx,
generated by cgit v1.2.3 (git 2.0.4) at 2025-12-14 19:37:25 +0000