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authorArnaldo Carvalho de Melo <acme@redhat.com>2017-04-28 03:21:09 +0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2017-05-03 00:23:04 +0300
commitb843f62ad942f3879c2d7acd27b44f931c609685 (patch)
tree5367408cae8262e00b559250bbfc6f8f222f5c38 /tools
parent96395cbbc7e94cbbe4f76cf64cf122fabc19123d (diff)
downloadlinux-b843f62ad942f3879c2d7acd27b44f931c609685.tar.xz
perf symbols: Accept symbols starting at address 0
That is the case of _text on s390, and we have some functions that return an address, using address zero to report problems, oops. This would lead the symbol loading routines to not use "_text" as the reference relocation symbol, or the first symbol for the kernel, but use instead "_stext", that is at the same address on x86_64 and others, but not on s390: [acme@localhost perf-4.11.0-rc6]$ head -15 /proc/kallsyms 0000000000000000 T _text 0000000000000418 t iplstart 0000000000000800 T start 000000000000080a t .base 000000000000082e t .sk8x8 0000000000000834 t .gotr 0000000000000842 t .cmd 0000000000000846 t .parm 000000000000084a t .lowcase 0000000000010000 T startup 0000000000010010 T startup_kdump 0000000000010214 t startup_kdump_relocated 0000000000011000 T startup_continue 00000000000112a0 T _ehead 0000000000100000 T _stext [acme@localhost perf-4.11.0-rc6]$ Which in turn would make 'perf test vmlinux' to fail because it wouldn't find the symbols before "_stext" in kallsyms. Fix it by using the return value only for errors and storing the address, when the symbol is successfully found, in a provided pointer arg. Before this patch: After: [acme@localhost perf-4.11.0-rc6]$ tools/perf/perf test -v 1 1: vmlinux symtab matches kallsyms : --- start --- test child forked, pid 40693 Looking at the vmlinux_path (8 entries long) Using /usr/lib/debug/lib/modules/3.10.0-654.el7.s390x/vmlinux for symbols ERR : 0: _text not on kallsyms ERR : 0x418: iplstart not on kallsyms ERR : 0x800: start not on kallsyms ERR : 0x80a: .base not on kallsyms ERR : 0x82e: .sk8x8 not on kallsyms ERR : 0x834: .gotr not on kallsyms ERR : 0x842: .cmd not on kallsyms ERR : 0x846: .parm not on kallsyms ERR : 0x84a: .lowcase not on kallsyms ERR : 0x10000: startup not on kallsyms ERR : 0x10010: startup_kdump not on kallsyms ERR : 0x10214: startup_kdump_relocated not on kallsyms ERR : 0x11000: startup_continue not on kallsyms ERR : 0x112a0: _ehead not on kallsyms <SNIP warnings> test child finished with -1 ---- end ---- vmlinux symtab matches kallsyms: FAILED! [acme@localhost perf-4.11.0-rc6]$ After: [acme@localhost perf-4.11.0-rc6]$ tools/perf/perf test -v 1 1: vmlinux symtab matches kallsyms : --- start --- test child forked, pid 47160 <SNIP warnings> test child finished with 0 ---- end ---- vmlinux symtab matches kallsyms: Ok [acme@localhost perf-4.11.0-rc6]$ Reported-by: Michael Petlan <mpetlan@redhat.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/n/tip-9x9bwgd3btwdk1u51xie93fz@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools')
-rw-r--r--tools/perf/builtin-buildid-cache.c13
-rw-r--r--tools/perf/util/event.c9
-rw-r--r--tools/perf/util/event.h4
-rw-r--r--tools/perf/util/machine.c28
-rw-r--r--tools/perf/util/symbol.c11
5 files changed, 37 insertions, 28 deletions
diff --git a/tools/perf/builtin-buildid-cache.c b/tools/perf/builtin-buildid-cache.c
index 64b44e81c771..9eba7f1add1f 100644
--- a/tools/perf/builtin-buildid-cache.c
+++ b/tools/perf/builtin-buildid-cache.c
@@ -49,19 +49,22 @@ static bool same_kallsyms_reloc(const char *from_dir, char *to_dir)
char to[PATH_MAX];
const char *name;
u64 addr1 = 0, addr2 = 0;
- int i;
+ int i, err = -1;
scnprintf(from, sizeof(from), "%s/kallsyms", from_dir);
scnprintf(to, sizeof(to), "%s/kallsyms", to_dir);
for (i = 0; (name = ref_reloc_sym_names[i]) != NULL; i++) {
- addr1 = kallsyms__get_function_start(from, name);
- if (addr1)
+ err = kallsyms__get_function_start(from, name, &addr1);
+ if (!err)
break;
}
- if (name)
- addr2 = kallsyms__get_function_start(to, name);
+ if (err)
+ return false;
+
+ if (kallsyms__get_function_start(to, name, &addr2))
+ return false;
return addr1 == addr2;
}
diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
index 437194fe0434..dc5c3bb69d73 100644
--- a/tools/perf/util/event.c
+++ b/tools/perf/util/event.c
@@ -768,15 +768,16 @@ static int find_symbol_cb(void *arg, const char *name, char type,
return 1;
}
-u64 kallsyms__get_function_start(const char *kallsyms_filename,
- const char *symbol_name)
+int kallsyms__get_function_start(const char *kallsyms_filename,
+ const char *symbol_name, u64 *addr)
{
struct process_symbol_args args = { .name = symbol_name, };
if (kallsyms__parse(kallsyms_filename, &args, find_symbol_cb) <= 0)
- return 0;
+ return -1;
- return args.start;
+ *addr = args.start;
+ return 0;
}
int perf_event__synthesize_kernel_mmap(struct perf_tool *tool,
diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h
index cfbe32bd7413..27ac047490c3 100644
--- a/tools/perf/util/event.h
+++ b/tools/perf/util/event.h
@@ -675,8 +675,8 @@ size_t perf_event__fprintf_cpu_map(union perf_event *event, FILE *fp);
size_t perf_event__fprintf_namespaces(union perf_event *event, FILE *fp);
size_t perf_event__fprintf(union perf_event *event, FILE *fp);
-u64 kallsyms__get_function_start(const char *kallsyms_filename,
- const char *symbol_name);
+int kallsyms__get_function_start(const char *kallsyms_filename,
+ const char *symbol_name, u64 *addr);
void *cpu_map_data__alloc(struct cpu_map *map, size_t *size, u16 *type, int *max);
void cpu_map_data__synthesize(struct cpu_map_data *data, struct cpu_map *map,
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 7a47f52ccfcc..d97e014c3df3 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -796,11 +796,11 @@ const char *ref_reloc_sym_names[] = {"_text", "_stext", NULL};
* Returns the name of the start symbol in *symbol_name. Pass in NULL as
* symbol_name if it's not that important.
*/
-static u64 machine__get_running_kernel_start(struct machine *machine,
- const char **symbol_name)
+static int machine__get_running_kernel_start(struct machine *machine,
+ const char **symbol_name, u64 *start)
{
char filename[PATH_MAX];
- int i;
+ int i, err = -1;
const char *name;
u64 addr = 0;
@@ -810,21 +810,28 @@ static u64 machine__get_running_kernel_start(struct machine *machine,
return 0;
for (i = 0; (name = ref_reloc_sym_names[i]) != NULL; i++) {
- addr = kallsyms__get_function_start(filename, name);
- if (addr)
+ err = kallsyms__get_function_start(filename, name, &addr);
+ if (!err)
break;
}
+ if (err)
+ return -1;
+
if (symbol_name)
*symbol_name = name;
- return addr;
+ *start = addr;
+ return 0;
}
int __machine__create_kernel_maps(struct machine *machine, struct dso *kernel)
{
int type;
- u64 start = machine__get_running_kernel_start(machine, NULL);
+ u64 start = 0;
+
+ if (machine__get_running_kernel_start(machine, NULL, &start))
+ return -1;
/* In case of renewal the kernel map, destroy previous one */
machine__destroy_kernel_maps(machine);
@@ -1185,8 +1192,8 @@ static int machine__create_modules(struct machine *machine)
int machine__create_kernel_maps(struct machine *machine)
{
struct dso *kernel = machine__get_kernel(machine);
- const char *name;
- u64 addr;
+ const char *name = NULL;
+ u64 addr = 0;
int ret;
if (kernel == NULL)
@@ -1211,8 +1218,7 @@ int machine__create_kernel_maps(struct machine *machine)
*/
map_groups__fixup_end(&machine->kmaps);
- addr = machine__get_running_kernel_start(machine, &name);
- if (!addr) {
+ if (machine__get_running_kernel_start(machine, &name, &addr)) {
} else if (maps__set_kallsyms_ref_reloc_sym(machine->vmlinux_maps, name, addr)) {
machine__destroy_kernel_maps(machine);
return -1;
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 2cb7665e9973..b349e8eda0e2 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -466,7 +466,7 @@ void dso__insert_symbol(struct dso *dso, enum map_type type, struct symbol *sym)
struct symbol *dso__find_symbol(struct dso *dso,
enum map_type type, u64 addr)
{
- if (dso->last_find_result[type].addr != addr) {
+ if (dso->last_find_result[type].addr != addr || dso->last_find_result[type].symbol == NULL) {
dso->last_find_result[type].addr = addr;
dso->last_find_result[type].symbol = symbols__find(&dso->symbols[type], addr);
}
@@ -1075,8 +1075,9 @@ static int validate_kcore_addresses(const char *kallsyms_filename,
if (kmap->ref_reloc_sym && kmap->ref_reloc_sym->name) {
u64 start;
- start = kallsyms__get_function_start(kallsyms_filename,
- kmap->ref_reloc_sym->name);
+ if (kallsyms__get_function_start(kallsyms_filename,
+ kmap->ref_reloc_sym->name, &start))
+ return -ENOENT;
if (start != kmap->ref_reloc_sym->addr)
return -EINVAL;
}
@@ -1248,9 +1249,7 @@ static int kallsyms__delta(struct map *map, const char *filename, u64 *delta)
if (!kmap->ref_reloc_sym || !kmap->ref_reloc_sym->name)
return 0;
- addr = kallsyms__get_function_start(filename,
- kmap->ref_reloc_sym->name);
- if (!addr)
+ if (kallsyms__get_function_start(filename, kmap->ref_reloc_sym->name, &addr))
return -1;
*delta = addr - kmap->ref_reloc_sym->addr;