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tools: bpf: move the event reading loop to libbpf 

There are two copies of event reading loop - in bpftool and
trace_helpers "library".  Consolidate them and move the code
to libbpf.  Return codes from trace_helpers are kept, but
renamed to include LIBBPF prefix.

Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
hifive-unleashed-5.1
Jakub Kicinski 2018-05-10 10:24:40 -07:00 committed by Daniel Borkmann
parent 5f9380572b
commit d0cabbb021
10 changed files with 138 additions and 122 deletions
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8
samples/bpf/Makefile
View File

@ -165,6 +165,14 @@ HOSTCFLAGS += -I$(srctree)/tools/lib/ -I$(srctree)/tools/include
HOSTCFLAGS += -I$(srctree)/tools/perf
HOSTCFLAGS_bpf_load.o += -I$(objtree)/usr/include -Wno-unused-variable
HOSTCFLAGS_trace_helpers.o += -I$(srctree)/tools/lib/bpf/
HOSTCFLAGS_trace_output_user.o += -I$(srctree)/tools/lib/bpf/
HOSTCFLAGS_offwaketime_user.o += -I$(srctree)/tools/lib/bpf/
HOSTCFLAGS_spintest_user.o += -I$(srctree)/tools/lib/bpf/
HOSTCFLAGS_trace_event_user.o += -I$(srctree)/tools/lib/bpf/
HOSTCFLAGS_sampleip_user.o += -I$(srctree)/tools/lib/bpf/
HOSTLOADLIBES_test_lru_dist += -lelf
HOSTLOADLIBES_sock_example += -lelf
HOSTLOADLIBES_fds_example += -lelf

6
samples/bpf/trace_output_user.c
View File

@ -48,7 +48,7 @@ static int print_bpf_output(void *data, int size)
if (e->cookie != 0x12345678) {
printf("BUG pid %llx cookie %llx sized %d\n",
e->pid, e->cookie, size);
return PERF_EVENT_ERROR;
return LIBBPF_PERF_EVENT_ERROR;
}
cnt++;
@ -56,10 +56,10 @@ static int print_bpf_output(void *data, int size)
if (cnt == MAX_CNT) {
printf("recv %lld events per sec\n",
MAX_CNT * 1000000000ll / (time_get_ns() - start_time));
return PERF_EVENT_DONE;
return LIBBPF_PERF_EVENT_DONE;
}
return PERF_EVENT_CONT;
return LIBBPF_PERF_EVENT_CONT;
}
static void test_bpf_perf_event(void)

64
tools/bpf/bpftool/map_perf_ring.c
View File

@ -50,14 +50,15 @@ static void int_exit(int signo)
stop = true;
}
static void
print_bpf_output(struct event_ring_info *ring, struct perf_event_sample *e)
static enum bpf_perf_event_ret print_bpf_output(void *event, void *priv)
{
struct event_ring_info *ring = priv;
struct perf_event_sample *e = event;
struct {
struct perf_event_header header;
__u64 id;
__u64 lost;
} *lost = (void *)e;
} *lost = event;
if (json_output) {
jsonw_start_object(json_wtr);
@ -96,60 +97,23 @@ print_bpf_output(struct event_ring_info *ring, struct perf_event_sample *e)
e->header.type, e->header.size);
}
}
return LIBBPF_PERF_EVENT_CONT;
}
static void
perf_event_read(struct event_ring_info *ring, void **buf, size_t *buf_len)
{
volatile struct perf_event_mmap_page *header = ring->mem;
__u64 buffer_size = MMAP_PAGE_CNT * get_page_size();
__u64 data_tail = header->data_tail;
__u64 data_head = header->data_head;
void *base, *begin, *end;
enum bpf_perf_event_ret ret;
asm volatile("" ::: "memory"); /* in real code it should be smp_rmb() */
if (data_head == data_tail)
return;
base = ((char *)header) + get_page_size();
begin = base + data_tail % buffer_size;
end = base + data_head % buffer_size;
while (begin != end) {
struct perf_event_sample *e;
e = begin;
if (begin + e->header.size > base + buffer_size) {
long len = base + buffer_size - begin;
if (*buf_len < e->header.size) {
free(*buf);
*buf = malloc(e->header.size);
if (!*buf) {
fprintf(stderr,
"can't allocate memory");
stop = true;
return;
}
*buf_len = e->header.size;
}
memcpy(*buf, begin, len);
memcpy(*buf + len, base, e->header.size - len);
e = (void *)*buf;
begin = base + e->header.size - len;
} else if (begin + e->header.size == base + buffer_size) {
begin = base;
} else {
begin += e->header.size;
}
print_bpf_output(ring, e);
ret = bpf_perf_event_read_simple(ring->mem,
MMAP_PAGE_CNT * get_page_size(),
get_page_size(), buf, buf_len,
print_bpf_output, ring);
if (ret != LIBBPF_PERF_EVENT_CONT) {
fprintf(stderr, "perf read loop failed with %d\n", ret);
stop = true;
}
__sync_synchronize(); /* smp_mb() */
header->data_tail = data_head;
}
static int perf_mmap_size(void)

2
tools/lib/bpf/Makefile
View File

@ -69,7 +69,7 @@ FEATURE_USER = .libbpf
FEATURE_TESTS = libelf libelf-getphdrnum libelf-mmap bpf
FEATURE_DISPLAY = libelf bpf
INCLUDES = -I. -I$(srctree)/tools/include -I$(srctree)/tools/arch/$(ARCH)/include/uapi -I$(srctree)/tools/include/uapi
INCLUDES = -I. -I$(srctree)/tools/include -I$(srctree)/tools/arch/$(ARCH)/include/uapi -I$(srctree)/tools/include/uapi -I$(srctree)/tools/perf
FEATURE_CHECK_CFLAGS-bpf = $(INCLUDES)
check_feat := 1

61
tools/lib/bpf/libbpf.c
View File

@ -31,6 +31,7 @@
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <perf-sys.h>
#include <asm/unistd.h>
#include <linux/err.h>
#include <linux/kernel.h>
@ -2210,3 +2211,63 @@ int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr,
*prog_fd = bpf_program__fd(first_prog);
return 0;
}
enum bpf_perf_event_ret
bpf_perf_event_read_simple(void *mem, unsigned long size,
unsigned long page_size, void **buf, size_t *buf_len,
bpf_perf_event_print_t fn, void *priv)
{
volatile struct perf_event_mmap_page *header = mem;
__u64 data_tail = header->data_tail;
__u64 data_head = header->data_head;
void *base, *begin, *end;
int ret;
asm volatile("" ::: "memory"); /* in real code it should be smp_rmb() */
if (data_head == data_tail)
return LIBBPF_PERF_EVENT_CONT;
base = ((char *)header) + page_size;
begin = base + data_tail % size;
end = base + data_head % size;
while (begin != end) {
struct perf_event_header *ehdr;
ehdr = begin;
if (begin + ehdr->size > base + size) {
long len = base + size - begin;
if (*buf_len < ehdr->size) {
free(*buf);
*buf = malloc(ehdr->size);
if (!*buf) {
ret = LIBBPF_PERF_EVENT_ERROR;
break;
}
*buf_len = ehdr->size;
}
memcpy(*buf, begin, len);
memcpy(*buf + len, base, ehdr->size - len);
ehdr = (void *)*buf;
begin = base + ehdr->size - len;
} else if (begin + ehdr->size == base + size) {
begin = base;
} else {
begin += ehdr->size;
}
ret = fn(ehdr, priv);
if (ret != LIBBPF_PERF_EVENT_CONT)
break;
data_tail += ehdr->size;
}
__sync_synchronize(); /* smp_mb() */
header->data_tail = data_tail;
return ret;
}

13
tools/lib/bpf/libbpf.h
View File

@ -267,4 +267,17 @@ int bpf_prog_load(const char *file, enum bpf_prog_type type,
struct bpf_object **pobj, int *prog_fd);
int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags);
enum bpf_perf_event_ret {
LIBBPF_PERF_EVENT_DONE = 0,
LIBBPF_PERF_EVENT_ERROR = -1,
LIBBPF_PERF_EVENT_CONT = -2,
};
typedef enum bpf_perf_event_ret (*bpf_perf_event_print_t)(void *event,
void *priv);
int bpf_perf_event_read_simple(void *mem, unsigned long size,
unsigned long page_size,
void **buf, size_t *buf_len,
bpf_perf_event_print_t fn, void *priv);
#endif

2
tools/testing/selftests/bpf/Makefile
View File

@ -10,7 +10,7 @@ ifneq ($(wildcard $(GENHDR)),)
GENFLAGS := -DHAVE_GENHDR
endif
CFLAGS += -Wall -O2 -I$(APIDIR) -I$(LIBDIR) -I$(GENDIR) $(GENFLAGS) -I../../../include
CFLAGS += -Wall -O2 -I$(APIDIR) -I$(LIBDIR) -I$(BPFDIR) -I$(GENDIR) $(GENFLAGS) -I../../../include
LDLIBS += -lcap -lelf -lrt -lpthread
TEST_CUSTOM_PROGS = $(OUTPUT)/urandom_read

6
tools/testing/selftests/bpf/test_progs.c
View File

@ -1337,12 +1337,12 @@ static int get_stack_print_output(void *data, int size)
good_user_stack = true;
}
if (!good_kern_stack || !good_user_stack)
return PERF_EVENT_ERROR;
return LIBBPF_PERF_EVENT_ERROR;
if (cnt == MAX_CNT_RAWTP)
return PERF_EVENT_DONE;
return LIBBPF_PERF_EVENT_DONE;
return PERF_EVENT_CONT;
return LIBBPF_PERF_EVENT_CONT;
}
static void test_get_stack_raw_tp(void)

87
tools/testing/selftests/bpf/trace_helpers.c
View File

@ -74,7 +74,7 @@ struct ksym *ksym_search(long key)
static int page_size;
static int page_cnt = 8;
static volatile struct perf_event_mmap_page *header;
static struct perf_event_mmap_page *header;
int perf_event_mmap(int fd)
{
@ -107,74 +107,47 @@ struct perf_event_sample {
char data[];
};
static int perf_event_read(perf_event_print_fn fn)
static enum bpf_perf_event_ret bpf_perf_event_print(void *event, void *priv)
{
__u64 data_tail = header->data_tail;
__u64 data_head = header->data_head;
__u64 buffer_size = page_cnt * page_size;
void *base, *begin, *end;
char buf[256];
struct perf_event_sample *e = event;
perf_event_print_fn fn = priv;
int ret;
asm volatile("" ::: "memory"); /* in real code it should be smp_rmb() */
if (data_head == data_tail)
return PERF_EVENT_CONT;
base = ((char *)header) + page_size;
begin = base + data_tail % buffer_size;
end = base + data_head % buffer_size;
while (begin != end) {
struct perf_event_sample *e;
e = begin;
if (begin + e->header.size > base + buffer_size) {
long len = base + buffer_size - begin;
assert(len < e->header.size);
memcpy(buf, begin, len);
memcpy(buf + len, base, e->header.size - len);
e = (void *) buf;
begin = base + e->header.size - len;
} else if (begin + e->header.size == base + buffer_size) {
begin = base;
} else {
begin += e->header.size;
}
if (e->header.type == PERF_RECORD_SAMPLE) {
ret = fn(e->data, e->size);
if (ret != PERF_EVENT_CONT)
return ret;
} else if (e->header.type == PERF_RECORD_LOST) {
struct {
struct perf_event_header header;
__u64 id;
__u64 lost;
} *lost = (void *) e;
printf("lost %lld events\n", lost->lost);
} else {
printf("unknown event type=%d size=%d\n",
e->header.type, e->header.size);
}
if (e->header.type == PERF_RECORD_SAMPLE) {
ret = fn(e->data, e->size);
if (ret != LIBBPF_PERF_EVENT_CONT)
return ret;
} else if (e->header.type == PERF_RECORD_LOST) {
struct {
struct perf_event_header header;
__u64 id;
__u64 lost;
} *lost = (void *) e;
printf("lost %lld events\n", lost->lost);
} else {
printf("unknown event type=%d size=%d\n",
e->header.type, e->header.size);
}
__sync_synchronize(); /* smp_mb() */
header->data_tail = data_head;
return PERF_EVENT_CONT;
return LIBBPF_PERF_EVENT_CONT;
}
int perf_event_poller(int fd, perf_event_print_fn output_fn)
{
int ret;
enum bpf_perf_event_ret ret;
void *buf = NULL;
size_t len = 0;
for (;;) {
perf_event_poll(fd);
ret = perf_event_read(output_fn);
if (ret != PERF_EVENT_CONT)
return ret;
ret = bpf_perf_event_read_simple(header, page_cnt * page_size,
page_size, &buf, &len,
bpf_perf_event_print,
output_fn);
if (ret != LIBBPF_PERF_EVENT_CONT)
break;
}
free(buf);
return PERF_EVENT_DONE;
return ret;
}

11
tools/testing/selftests/bpf/trace_helpers.h
View File

@ -2,6 +2,8 @@
#ifndef __TRACE_HELPER_H
#define __TRACE_HELPER_H
#include <libbpf.h>
struct ksym {
long addr;
char *name;
@ -10,14 +12,9 @@ struct ksym {
int load_kallsyms(void);
struct ksym *ksym_search(long key);
typedef int (*perf_event_print_fn)(void *data, int size);
/* return code for perf_event_print_fn */
#define PERF_EVENT_DONE 0
#define PERF_EVENT_ERROR -1
#define PERF_EVENT_CONT -2
typedef enum bpf_perf_event_ret (*perf_event_print_fn)(void *data, int size);
int perf_event_mmap(int fd);
/* return PERF_EVENT_DONE or PERF_EVENT_ERROR */
/* return LIBBPF_PERF_EVENT_DONE or LIBBPF_PERF_EVENT_ERROR */
int perf_event_poller(int fd, perf_event_print_fn output_fn);
#endif