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-rw-r--r--tools/perf/util/symbol-elf.c79
1 files changed, 76 insertions, 3 deletions
diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index 4b934ed3bf..0b91f813c4 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -23,6 +23,7 @@
#include <linux/ctype.h>
#include <linux/kernel.h>
#include <linux/zalloc.h>
+#include <linux/string.h>
#include <symbol/kallsyms.h>
#include <internal/lib.h>
@@ -1329,6 +1330,58 @@ out_close:
return -1;
}
+static bool is_exe_text(int flags)
+{
+ return (flags & (SHF_ALLOC | SHF_EXECINSTR)) == (SHF_ALLOC | SHF_EXECINSTR);
+}
+
+/*
+ * Some executable module sections like .noinstr.text might be laid out with
+ * .text so they can use the same mapping (memory address to file offset).
+ * Check if that is the case. Refer to kernel layout_sections(). Return the
+ * maximum offset.
+ */
+static u64 max_text_section(Elf *elf, GElf_Ehdr *ehdr)
+{
+ Elf_Scn *sec = NULL;
+ GElf_Shdr shdr;
+ u64 offs = 0;
+
+ /* Doesn't work for some arch */
+ if (ehdr->e_machine == EM_PARISC ||
+ ehdr->e_machine == EM_ALPHA)
+ return 0;
+
+ /* ELF is corrupted/truncated, avoid calling elf_strptr. */
+ if (!elf_rawdata(elf_getscn(elf, ehdr->e_shstrndx), NULL))
+ return 0;
+
+ while ((sec = elf_nextscn(elf, sec)) != NULL) {
+ char *sec_name;
+
+ if (!gelf_getshdr(sec, &shdr))
+ break;
+
+ if (!is_exe_text(shdr.sh_flags))
+ continue;
+
+ /* .init and .exit sections are not placed with .text */
+ sec_name = elf_strptr(elf, ehdr->e_shstrndx, shdr.sh_name);
+ if (!sec_name ||
+ strstarts(sec_name, ".init") ||
+ strstarts(sec_name, ".exit"))
+ break;
+
+ /* Must be next to previous, assumes .text is first */
+ if (offs && PERF_ALIGN(offs, shdr.sh_addralign ?: 1) != shdr.sh_offset)
+ break;
+
+ offs = shdr.sh_offset + shdr.sh_size;
+ }
+
+ return offs;
+}
+
/**
* ref_reloc_sym_not_found - has kernel relocation symbol been found.
* @kmap: kernel maps and relocation reference symbol
@@ -1368,7 +1421,8 @@ static int dso__process_kernel_symbol(struct dso *dso, struct map *map,
struct maps *kmaps, struct kmap *kmap,
struct dso **curr_dsop, struct map **curr_mapp,
const char *section_name,
- bool adjust_kernel_syms, bool kmodule, bool *remap_kernel)
+ bool adjust_kernel_syms, bool kmodule, bool *remap_kernel,
+ u64 max_text_sh_offset)
{
struct dso *curr_dso = *curr_dsop;
struct map *curr_map;
@@ -1424,6 +1478,17 @@ static int dso__process_kernel_symbol(struct dso *dso, struct map *map,
if (!kmap)
return 0;
+ /*
+ * perf does not record module section addresses except for .text, but
+ * some sections can use the same mapping as .text.
+ */
+ if (kmodule && adjust_kernel_syms && is_exe_text(shdr->sh_flags) &&
+ shdr->sh_offset <= max_text_sh_offset) {
+ *curr_mapp = map;
+ *curr_dsop = dso;
+ return 0;
+ }
+
snprintf(dso_name, sizeof(dso_name), "%s%s", dso->short_name, section_name);
curr_map = maps__find_by_name(kmaps, dso_name);
@@ -1470,8 +1535,10 @@ static int dso__process_kernel_symbol(struct dso *dso, struct map *map,
dso__set_loaded(curr_dso);
*curr_mapp = curr_map;
*curr_dsop = curr_dso;
- } else
+ } else {
*curr_dsop = map__dso(curr_map);
+ map__put(curr_map);
+ }
return 0;
}
@@ -1497,6 +1564,7 @@ dso__load_sym_internal(struct dso *dso, struct map *map, struct symsrc *syms_ss,
Elf *elf;
int nr = 0;
bool remap_kernel = false, adjust_kernel_syms = false;
+ u64 max_text_sh_offset = 0;
if (kmap && !kmaps)
return -1;
@@ -1584,6 +1652,10 @@ dso__load_sym_internal(struct dso *dso, struct map *map, struct symsrc *syms_ss,
remap_kernel = true;
adjust_kernel_syms = dso->adjust_symbols;
}
+
+ if (kmodule && adjust_kernel_syms)
+ max_text_sh_offset = max_text_section(runtime_ss->elf, &runtime_ss->ehdr);
+
elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
struct symbol *f;
const char *elf_name = elf_sym__name(&sym, symstrs);
@@ -1673,7 +1745,8 @@ dso__load_sym_internal(struct dso *dso, struct map *map, struct symsrc *syms_ss,
if (dso->kernel) {
if (dso__process_kernel_symbol(dso, map, &sym, &shdr, kmaps, kmap, &curr_dso, &curr_map,
- section_name, adjust_kernel_syms, kmodule, &remap_kernel))
+ section_name, adjust_kernel_syms, kmodule,
+ &remap_kernel, max_text_sh_offset))
goto out_elf_end;
} else if ((used_opd && runtime_ss->adjust_symbols) ||
(!used_opd && syms_ss->adjust_symbols)) {