perf tools: Make it possible to read object code from vmlinux
The new "object code reading" test shows that it is not possible to read
object code from vmlinux. That is because the mappings do not map to
the dso. This patch fixes that.
A side-effect of changing the kernel map is that the "reloc" offset must
be taken into account. As a result of that separate map functions for
relocation are no longer needed.
Also fixing up the maps to match the symbols no longer makes sense and
so is not done.
The vmlinux dso data_type is now set to either DSO_BINARY_TYPE__VMLINUX
or DSO_BINARY_TYPE__GUEST_VMLINUX as approprite, which enables the
correct file name to be determined by dso__binary_type_file().
This patch breaks the "vmlinux symtab matches kallsyms" test. That is
fixed in a following patch.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1375875537-4509-4-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index c4374f0..121583d 100644
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -78,6 +78,8 @@
symbol_conf.symfs, build_id_hex, build_id_hex + 2);
break;
+ case DSO_BINARY_TYPE__VMLINUX:
+ case DSO_BINARY_TYPE__GUEST_VMLINUX:
case DSO_BINARY_TYPE__SYSTEM_PATH_DSO:
snprintf(file, size, "%s%s",
symbol_conf.symfs, dso->long_name);
@@ -95,9 +97,7 @@
default:
case DSO_BINARY_TYPE__KALLSYMS:
- case DSO_BINARY_TYPE__VMLINUX:
case DSO_BINARY_TYPE__GUEST_KALLSYMS:
- case DSO_BINARY_TYPE__GUEST_VMLINUX:
case DSO_BINARY_TYPE__JAVA_JIT:
case DSO_BINARY_TYPE__NOT_FOUND:
ret = -1;
diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h
index d51aaf2..02aadaf 100644
--- a/tools/perf/util/dso.h
+++ b/tools/perf/util/dso.h
@@ -3,6 +3,7 @@
#include <linux/types.h>
#include <linux/rbtree.h>
+#include <stdbool.h>
#include "types.h"
#include "map.h"
@@ -146,4 +147,11 @@
size_t dso__fprintf_symbols_by_name(struct dso *dso,
enum map_type type, FILE *fp);
size_t dso__fprintf(struct dso *dso, enum map_type type, FILE *fp);
+
+static inline bool dso__is_vmlinux(struct dso *dso)
+{
+ return dso->data_type == DSO_BINARY_TYPE__VMLINUX ||
+ dso->data_type == DSO_BINARY_TYPE__GUEST_VMLINUX;
+}
+
#endif /* __PERF_DSO */
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index f9f9d63..dc35dcf 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -628,10 +628,8 @@
struct map *map = machine->vmlinux_maps[type];
int ret = dso__load_vmlinux_path(map->dso, map, filter);
- if (ret > 0) {
+ if (ret > 0)
dso__set_loaded(map->dso, type);
- map__reloc_vmlinux(map);
- }
return ret;
}
diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index 8bcdf9e..5f662a3 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -182,12 +182,6 @@
#endif
return -1;
}
- /*
- * Only applies to the kernel, as its symtabs aren't relative like the
- * module ones.
- */
- if (map->dso->kernel)
- map__reloc_vmlinux(map);
return 0;
}
@@ -513,35 +507,6 @@
return 0;
}
-static u64 map__reloc_map_ip(struct map *map, u64 ip)
-{
- return ip + (s64)map->pgoff;
-}
-
-static u64 map__reloc_unmap_ip(struct map *map, u64 ip)
-{
- return ip - (s64)map->pgoff;
-}
-
-void map__reloc_vmlinux(struct map *map)
-{
- struct kmap *kmap = map__kmap(map);
- s64 reloc;
-
- if (!kmap->ref_reloc_sym || !kmap->ref_reloc_sym->unrelocated_addr)
- return;
-
- reloc = (kmap->ref_reloc_sym->unrelocated_addr -
- kmap->ref_reloc_sym->addr);
-
- if (!reloc)
- return;
-
- map->map_ip = map__reloc_map_ip;
- map->unmap_ip = map__reloc_unmap_ip;
- map->pgoff = reloc;
-}
-
void maps__insert(struct rb_root *maps, struct map *map)
{
struct rb_node **p = &maps->rb_node;
diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index 4b12bf8..ed6f443 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -603,7 +603,7 @@
".gnu.prelink_undo",
NULL) != NULL);
} else {
- ss->adjust_symbols = 0;
+ ss->adjust_symbols = ehdr.e_type == ET_EXEC;
}
ss->name = strdup(name);
@@ -624,6 +624,37 @@
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)
@@ -642,6 +673,7 @@
Elf_Scn *sec, *sec_strndx;
Elf *elf;
int nr = 0;
+ bool remap_kernel = false, adjust_kernel_syms = false;
dso->symtab_type = syms_ss->type;
@@ -681,7 +713,31 @@
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 +746,6 @@
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;
@@ -745,15 +797,37 @@
(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);
+ }
+
curr_map = map;
curr_dso = dso;
goto new_symbol;
@@ -781,8 +855,16 @@
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);
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index ea62ecd..04300dd 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -917,6 +917,10 @@
symsrc__destroy(&ss);
if (err > 0) {
+ if (dso->kernel == DSO_TYPE_GUEST_KERNEL)
+ dso->data_type = DSO_BINARY_TYPE__GUEST_VMLINUX;
+ else
+ dso->data_type = DSO_BINARY_TYPE__VMLINUX;
dso__set_long_name(dso, (char *)vmlinux);
dso__set_loaded(dso, map->type);
pr_debug("Using %s for symbols\n", symfs_vmlinux);
@@ -989,7 +993,7 @@
dso__set_long_name(dso,
strdup(symbol_conf.vmlinux_name));
dso->lname_alloc = 1;
- goto out_fixup;
+ return err;
}
return err;
}
@@ -997,7 +1001,7 @@
if (vmlinux_path != NULL) {
err = dso__load_vmlinux_path(dso, map, filter);
if (err > 0)
- goto out_fixup;
+ return err;
}
/* do not try local files if a symfs was given */
@@ -1058,7 +1062,6 @@
if (err > 0) {
dso__set_long_name(dso, strdup("[kernel.kallsyms]"));
-out_fixup:
map__fixup_start(map);
map__fixup_end(map);
}
@@ -1089,7 +1092,7 @@
if (symbol_conf.default_guest_vmlinux_name != NULL) {
err = dso__load_vmlinux(dso, map,
symbol_conf.default_guest_vmlinux_name, filter);
- goto out_try_fixup;
+ return err;
}
kallsyms_filename = symbol_conf.default_guest_kallsyms;
@@ -1101,15 +1104,10 @@
}
err = dso__load_kallsyms(dso, kallsyms_filename, map, filter);
- if (err > 0)
- pr_debug("Using %s for symbols\n", kallsyms_filename);
-
-out_try_fixup:
if (err > 0) {
- if (kallsyms_filename != NULL) {
- machine__mmap_name(machine, path, sizeof(path));
- dso__set_long_name(dso, strdup(path));
- }
+ pr_debug("Using %s for symbols\n", kallsyms_filename);
+ machine__mmap_name(machine, path, sizeof(path));
+ dso__set_long_name(dso, strdup(path));
map__fixup_start(map);
map__fixup_end(map);
}