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-rw-r--r--tools/perf/util/symbol-elf.c174
1 files changed, 165 insertions, 9 deletions
diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index 4b12bf85032..a7b9ab55738 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -599,11 +599,13 @@ int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
if (dso->kernel == DSO_TYPE_USER) {
GElf_Shdr shdr;
ss->adjust_symbols = (ehdr.e_type == ET_EXEC ||
+ ehdr.e_type == ET_REL ||
elf_section_by_name(elf, &ehdr, &shdr,
".gnu.prelink_undo",
NULL) != NULL);
} else {
- ss->adjust_symbols = 0;
+ ss->adjust_symbols = ehdr.e_type == ET_EXEC ||
+ ehdr.e_type == ET_REL;
}
ss->name = strdup(name);
@@ -624,6 +626,37 @@ out_close:
return err;
}
+/**
+ * ref_reloc_sym_not_found - has kernel relocation symbol been found.
+ * @kmap: kernel maps and relocation reference symbol
+ *
+ * This function returns %true if we are dealing with the kernel maps and the
+ * relocation reference symbol has not yet been found. Otherwise %false is
+ * returned.
+ */
+static bool ref_reloc_sym_not_found(struct kmap *kmap)
+{
+ return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
+ !kmap->ref_reloc_sym->unrelocated_addr;
+}
+
+/**
+ * ref_reloc - kernel relocation offset.
+ * @kmap: kernel maps and relocation reference symbol
+ *
+ * This function returns the offset of kernel addresses as determined by using
+ * the relocation reference symbol i.e. if the kernel has not been relocated
+ * then the return value is zero.
+ */
+static u64 ref_reloc(struct kmap *kmap)
+{
+ if (kmap && kmap->ref_reloc_sym &&
+ kmap->ref_reloc_sym->unrelocated_addr)
+ return kmap->ref_reloc_sym->addr -
+ kmap->ref_reloc_sym->unrelocated_addr;
+ return 0;
+}
+
int dso__load_sym(struct dso *dso, struct map *map,
struct symsrc *syms_ss, struct symsrc *runtime_ss,
symbol_filter_t filter, int kmodule)
@@ -642,8 +675,17 @@ int dso__load_sym(struct dso *dso, struct map *map,
Elf_Scn *sec, *sec_strndx;
Elf *elf;
int nr = 0;
+ bool remap_kernel = false, adjust_kernel_syms = false;
dso->symtab_type = syms_ss->type;
+ dso->rel = syms_ss->ehdr.e_type == ET_REL;
+
+ /*
+ * Modules may already have symbols from kallsyms, but those symbols
+ * have the wrong values for the dso maps, so remove them.
+ */
+ if (kmodule && syms_ss->symtab)
+ symbols__delete(&dso->symbols[map->type]);
if (!syms_ss->symtab) {
syms_ss->symtab = syms_ss->dynsym;
@@ -681,7 +723,31 @@ int dso__load_sym(struct dso *dso, struct map *map,
nr_syms = shdr.sh_size / shdr.sh_entsize;
memset(&sym, 0, sizeof(sym));
- dso->adjust_symbols = runtime_ss->adjust_symbols;
+
+ /*
+ * The kernel relocation symbol is needed in advance in order to adjust
+ * kernel maps correctly.
+ */
+ if (ref_reloc_sym_not_found(kmap)) {
+ elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
+ const char *elf_name = elf_sym__name(&sym, symstrs);
+
+ if (strcmp(elf_name, kmap->ref_reloc_sym->name))
+ continue;
+ kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
+ break;
+ }
+ }
+
+ dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
+ /*
+ * Initial kernel and module mappings do not map to the dso. For
+ * function mappings, flag the fixups.
+ */
+ if (map->type == MAP__FUNCTION && (dso->kernel || kmodule)) {
+ remap_kernel = true;
+ adjust_kernel_syms = dso->adjust_symbols;
+ }
elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
struct symbol *f;
const char *elf_name = elf_sym__name(&sym, symstrs);
@@ -690,10 +756,6 @@ int dso__load_sym(struct dso *dso, struct map *map,
const char *section_name;
bool used_opd = false;
- if (kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
- strcmp(elf_name, kmap->ref_reloc_sym->name) == 0)
- kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
-
if (!is_label && !elf_sym__is_a(&sym, map->type))
continue;
@@ -745,20 +807,55 @@ int dso__load_sym(struct dso *dso, struct map *map,
(sym.st_value & 1))
--sym.st_value;
- if (dso->kernel != DSO_TYPE_USER || kmodule) {
+ if (dso->kernel || kmodule) {
char dso_name[PATH_MAX];
+ /* Adjust symbol to map to file offset */
+ if (adjust_kernel_syms)
+ sym.st_value -= shdr.sh_addr - shdr.sh_offset;
+
if (strcmp(section_name,
(curr_dso->short_name +
dso->short_name_len)) == 0)
goto new_symbol;
if (strcmp(section_name, ".text") == 0) {
+ /*
+ * The initial kernel mapping is based on
+ * kallsyms and identity maps. Overwrite it to
+ * map to the kernel dso.
+ */
+ if (remap_kernel && dso->kernel) {
+ remap_kernel = false;
+ map->start = shdr.sh_addr +
+ ref_reloc(kmap);
+ map->end = map->start + shdr.sh_size;
+ map->pgoff = shdr.sh_offset;
+ map->map_ip = map__map_ip;
+ map->unmap_ip = map__unmap_ip;
+ /* Ensure maps are correctly ordered */
+ map_groups__remove(kmap->kmaps, map);
+ map_groups__insert(kmap->kmaps, map);
+ }
+
+ /*
+ * The initial module mapping is based on
+ * /proc/modules mapped to offset zero.
+ * Overwrite it to map to the module dso.
+ */
+ if (remap_kernel && kmodule) {
+ remap_kernel = false;
+ map->pgoff = shdr.sh_offset;
+ }
+
curr_map = map;
curr_dso = dso;
goto new_symbol;
}
+ if (!kmap)
+ goto new_symbol;
+
snprintf(dso_name, sizeof(dso_name),
"%s%s", dso->short_name, section_name);
@@ -781,8 +878,16 @@ int dso__load_sym(struct dso *dso, struct map *map,
dso__delete(curr_dso);
goto out_elf_end;
}
- curr_map->map_ip = identity__map_ip;
- curr_map->unmap_ip = identity__map_ip;
+ if (adjust_kernel_syms) {
+ curr_map->start = shdr.sh_addr +
+ ref_reloc(kmap);
+ curr_map->end = curr_map->start +
+ shdr.sh_size;
+ curr_map->pgoff = shdr.sh_offset;
+ } else {
+ curr_map->map_ip = identity__map_ip;
+ curr_map->unmap_ip = identity__map_ip;
+ }
curr_dso->symtab_type = dso->symtab_type;
map_groups__insert(kmap->kmaps, curr_map);
dsos__add(&dso->node, curr_dso);
@@ -846,6 +951,57 @@ out_elf_end:
return err;
}
+static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
+{
+ GElf_Phdr phdr;
+ size_t i, phdrnum;
+ int err;
+ u64 sz;
+
+ if (elf_getphdrnum(elf, &phdrnum))
+ return -1;
+
+ for (i = 0; i < phdrnum; i++) {
+ if (gelf_getphdr(elf, i, &phdr) == NULL)
+ return -1;
+ if (phdr.p_type != PT_LOAD)
+ continue;
+ if (exe) {
+ if (!(phdr.p_flags & PF_X))
+ continue;
+ } else {
+ if (!(phdr.p_flags & PF_R))
+ continue;
+ }
+ sz = min(phdr.p_memsz, phdr.p_filesz);
+ if (!sz)
+ continue;
+ err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
+ if (err)
+ return err;
+ }
+ return 0;
+}
+
+int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
+ bool *is_64_bit)
+{
+ int err;
+ Elf *elf;
+
+ elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
+ if (elf == NULL)
+ return -1;
+
+ if (is_64_bit)
+ *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
+
+ err = elf_read_maps(elf, exe, mapfn, data);
+
+ elf_end(elf);
+ return err;
+}
+
void symbol__elf_init(void)
{
elf_version(EV_CURRENT);