Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
perf dso: Add support for reading the e_machine type for a dso
For ELF file dsos read the e_machine from the ELF header. For kernel
types assume the e_machine matches the perf tool. In other cases
return EM_NONE.
When reading from the ELF header use DSO__SWAP that may need
dso->needs_swap initializing. Factor out dso__swap_init to allow this.
Signed-off-by: Ian Rogers <irogers@google.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Link: https://lore.kernel.org/r/20250319050741.269828-7-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
authored by
Ian Rogers
and committed by
Namhyung Kim
afffec6f
5c2938fe
+92
-27
+89
tools/perf/util/dso.c
+89
tools/perf/util/dso.c
···
1194
1194
return data_read_write_offset(dso, machine, offset, data, size, true);
1195
1195
}
1196
1196
1197
+
uint16_t dso__e_machine(struct dso *dso, struct machine *machine)
1198
+
{
1199
+
uint16_t e_machine = EM_NONE;
1200
+
int fd;
1201
+
1202
+
switch (dso__binary_type(dso)) {
1203
+
case DSO_BINARY_TYPE__KALLSYMS:
1204
+
case DSO_BINARY_TYPE__GUEST_KALLSYMS:
1205
+
case DSO_BINARY_TYPE__VMLINUX:
1206
+
case DSO_BINARY_TYPE__GUEST_VMLINUX:
1207
+
case DSO_BINARY_TYPE__GUEST_KMODULE:
1208
+
case DSO_BINARY_TYPE__GUEST_KMODULE_COMP:
1209
+
case DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE:
1210
+
case DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE_COMP:
1211
+
case DSO_BINARY_TYPE__KCORE:
1212
+
case DSO_BINARY_TYPE__GUEST_KCORE:
1213
+
case DSO_BINARY_TYPE__BPF_PROG_INFO:
1214
+
case DSO_BINARY_TYPE__BPF_IMAGE:
1215
+
case DSO_BINARY_TYPE__OOL:
1216
+
case DSO_BINARY_TYPE__JAVA_JIT:
1217
+
return EM_HOST;
1218
+
case DSO_BINARY_TYPE__DEBUGLINK:
1219
+
case DSO_BINARY_TYPE__BUILD_ID_CACHE:
1220
+
case DSO_BINARY_TYPE__BUILD_ID_CACHE_DEBUGINFO:
1221
+
case DSO_BINARY_TYPE__GNU_DEBUGDATA:
1222
+
case DSO_BINARY_TYPE__SYSTEM_PATH_DSO:
1223
+
case DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO:
1224
+
case DSO_BINARY_TYPE__FEDORA_DEBUGINFO:
1225
+
case DSO_BINARY_TYPE__UBUNTU_DEBUGINFO:
1226
+
case DSO_BINARY_TYPE__MIXEDUP_UBUNTU_DEBUGINFO:
1227
+
case DSO_BINARY_TYPE__BUILDID_DEBUGINFO:
1228
+
break;
1229
+
case DSO_BINARY_TYPE__NOT_FOUND:
1230
+
default:
1231
+
return EM_NONE;
1232
+
}
1233
+
1234
+
mutex_lock(dso__data_open_lock());
1235
+
1236
+
/*
1237
+
* dso__data(dso)->fd might be closed if other thread opened another
1238
+
* file (dso) due to open file limit (RLIMIT_NOFILE).
1239
+
*/
1240
+
try_to_open_dso(dso, machine);
1241
+
fd = dso__data(dso)->fd;
1242
+
if (fd >= 0) {
1243
+
_Static_assert(offsetof(Elf32_Ehdr, e_machine) == 18, "Unexpected offset");
1244
+
_Static_assert(offsetof(Elf64_Ehdr, e_machine) == 18, "Unexpected offset");
1245
+
if (dso__needs_swap(dso) == DSO_SWAP__UNSET) {
1246
+
unsigned char eidata;
1247
+
1248
+
if (pread(fd, &eidata, sizeof(eidata), EI_DATA) == sizeof(eidata))
1249
+
dso__swap_init(dso, eidata);
1250
+
}
1251
+
if (dso__needs_swap(dso) != DSO_SWAP__UNSET &&
1252
+
pread(fd, &e_machine, sizeof(e_machine), 18) == sizeof(e_machine))
1253
+
e_machine = DSO__SWAP(dso, uint16_t, e_machine);
1254
+
}
1255
+
mutex_unlock(dso__data_open_lock());
1256
+
return e_machine;
1257
+
}
1258
+
1197
1259
/**
1198
1260
* dso__data_read_addr - Read data from dso address
1199
1261
* @dso: dso object
···
1609
1547
dso__delete(dso);
1610
1548
else
1611
1549
RC_CHK_PUT(dso);
1550
+
}
1551
+
1552
+
int dso__swap_init(struct dso *dso, unsigned char eidata)
1553
+
{
1554
+
static unsigned int const endian = 1;
1555
+
1556
+
dso__set_needs_swap(dso, DSO_SWAP__NO);
1557
+
1558
+
switch (eidata) {
1559
+
case ELFDATA2LSB:
1560
+
/* We are big endian, DSO is little endian. */
1561
+
if (*(unsigned char const *)&endian != 1)
1562
+
dso__set_needs_swap(dso, DSO_SWAP__YES);
1563
+
break;
1564
+
1565
+
case ELFDATA2MSB:
1566
+
/* We are little endian, DSO is big endian. */
1567
+
if (*(unsigned char const *)&endian != 0)
1568
+
dso__set_needs_swap(dso, DSO_SWAP__YES);
1569
+
break;
1570
+
1571
+
default:
1572
+
pr_err("unrecognized DSO data encoding %d\n", eidata);
1573
+
return -EINVAL;
1574
+
}
1575
+
1576
+
return 0;
1612
1577
}
1613
1578
1614
1579
void dso__set_build_id(struct dso *dso, struct build_id *bid)
+3
tools/perf/util/dso.h
+3
tools/perf/util/dso.h
···
737
737
void dso__set_sorted_by_name(struct dso *dso);
738
738
void dso__sort_by_name(struct dso *dso);
739
739
740
+
int dso__swap_init(struct dso *dso, unsigned char eidata);
741
+
740
742
void dso__set_build_id(struct dso *dso, struct build_id *bid);
741
743
bool dso__build_id_equal(const struct dso *dso, struct build_id *bid);
742
744
void dso__read_running_kernel_build_id(struct dso *dso,
···
828
826
off_t dso__data_size(struct dso *dso, struct machine *machine);
829
827
ssize_t dso__data_read_offset(struct dso *dso, struct machine *machine,
830
828
u64 offset, u8 *data, ssize_t size);
829
+
uint16_t dso__e_machine(struct dso *dso, struct machine *machine);
831
830
ssize_t dso__data_read_addr(struct dso *dso, struct map *map,
832
831
struct machine *machine, u64 addr,
833
832
u8 *data, ssize_t size);
-27
tools/perf/util/symbol-elf.c
-27
tools/perf/util/symbol-elf.c
···
1174
1174
1175
1175
#endif
1176
1176
1177
-
static int dso__swap_init(struct dso *dso, unsigned char eidata)
1178
-
{
1179
-
static unsigned int const endian = 1;
1180
-
1181
-
dso__set_needs_swap(dso, DSO_SWAP__NO);
1182
-
1183
-
switch (eidata) {
1184
-
case ELFDATA2LSB:
1185
-
/* We are big endian, DSO is little endian. */
1186
-
if (*(unsigned char const *)&endian != 1)
1187
-
dso__set_needs_swap(dso, DSO_SWAP__YES);
1188
-
break;
1189
-
1190
-
case ELFDATA2MSB:
1191
-
/* We are little endian, DSO is big endian. */
1192
-
if (*(unsigned char const *)&endian != 0)
1193
-
dso__set_needs_swap(dso, DSO_SWAP__YES);
1194
-
break;
1195
-
1196
-
default:
1197
-
pr_err("unrecognized DSO data encoding %d\n", eidata);
1198
-
return -EINVAL;
1199
-
}
1200
-
1201
-
return 0;
1202
-
}
1203
-
1204
1177
bool symsrc__possibly_runtime(struct symsrc *ss)
1205
1178
{
1206
1179
return ss->dynsym || ss->opdsec;