The test sets a hardware breakpoint and uses a bpf program to suppress the I/O availability signal if the ip matches the expected value.
Signed-off-by: Kyle Huey khuey@kylehuey.com --- .../selftests/bpf/prog_tests/perf_skip.c | 95 +++++++++++++++++++ .../selftests/bpf/progs/test_perf_skip.c | 23 +++++ 2 files changed, 118 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/perf_skip.c create mode 100644 tools/testing/selftests/bpf/progs/test_perf_skip.c
diff --git a/tools/testing/selftests/bpf/prog_tests/perf_skip.c b/tools/testing/selftests/bpf/prog_tests/perf_skip.c new file mode 100644 index 000000000000..b269a31669b7 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/perf_skip.c @@ -0,0 +1,95 @@ +// SPDX-License-Identifier: GPL-2.0 +#define _GNU_SOURCE +#include <test_progs.h> +#include "test_perf_skip.skel.h" +#include <linux/hw_breakpoint.h> +#include <sys/mman.h> + +#define BPF_OBJECT "test_perf_skip.bpf.o" + +static void handle_sig(int) +{ + ASSERT_OK(1, "perf event not skipped"); +} + +static noinline int test_function(void) +{ + return 0; +} + +void serial_test_perf_skip(void) +{ + sighandler_t previous; + int duration = 0; + struct test_perf_skip *skel = NULL; + int map_fd = -1; + long page_size = sysconf(_SC_PAGE_SIZE); + uintptr_t *ip = NULL; + int prog_fd = -1; + struct perf_event_attr attr = {0}; + int perf_fd = -1; + struct f_owner_ex owner; + int err; + + previous = signal(SIGIO, handle_sig); + + skel = test_perf_skip__open_and_load(); + if (!ASSERT_OK_PTR(skel, "skel_load")) + goto cleanup; + + prog_fd = bpf_program__fd(skel->progs.handler); + if (!ASSERT_OK(prog_fd < 0, "bpf_program__fd")) + goto cleanup; + + map_fd = bpf_map__fd(skel->maps.ip); + if (!ASSERT_OK(map_fd < 0, "bpf_map__fd")) + goto cleanup; + + ip = mmap(NULL, page_size, PROT_READ | PROT_WRITE, MAP_SHARED, map_fd, 0); + if (!ASSERT_OK_PTR(ip, "mmap bpf map")) + goto cleanup; + + *ip = (uintptr_t)test_function; + + attr.type = PERF_TYPE_BREAKPOINT; + attr.size = sizeof(attr); + attr.bp_type = HW_BREAKPOINT_X; + attr.bp_addr = (uintptr_t)test_function; + attr.bp_len = sizeof(long); + attr.sample_period = 1; + attr.sample_type = PERF_SAMPLE_IP; + attr.pinned = 1; + attr.exclude_kernel = 1; + attr.exclude_hv = 1; + attr.precise_ip = 3; + + perf_fd = syscall(__NR_perf_event_open, &attr, 0, -1, -1, 0); + if (CHECK(perf_fd < 0, "perf_event_open", "err %d\n", perf_fd)) + goto cleanup; + + err = fcntl(perf_fd, F_SETFL, O_ASYNC); + if (!ASSERT_OK(err, "fcntl(F_SETFL, O_ASYNC)")) + goto cleanup; + + owner.type = F_OWNER_TID; + owner.pid = gettid(); + err = fcntl(perf_fd, F_SETOWN_EX, &owner); + if (!ASSERT_OK(err, "fcntl(F_SETOWN_EX)")) + goto cleanup; + + err = ioctl(perf_fd, PERF_EVENT_IOC_SET_BPF, prog_fd); + if (!ASSERT_OK(err, "ioctl(PERF_EVENT_IOC_SET_BPF)")) + goto cleanup; + + test_function(); + +cleanup: + if (perf_fd >= 0) + close(perf_fd); + if (ip) + munmap(ip, page_size); + if (skel) + test_perf_skip__destroy(skel); + + signal(SIGIO, previous); +} diff --git a/tools/testing/selftests/bpf/progs/test_perf_skip.c b/tools/testing/selftests/bpf/progs/test_perf_skip.c new file mode 100644 index 000000000000..ef01a9161afe --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_perf_skip.c @@ -0,0 +1,23 @@ +// SPDX-License-Identifier: GPL-2.0 +#include "vmlinux.h" +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h> + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __uint(max_entries, 1); + __uint(map_flags, BPF_F_MMAPABLE); + __type(key, uint32_t); + __type(value, uintptr_t); +} ip SEC(".maps"); + +SEC("perf_event") +int handler(struct bpf_perf_event_data *data) +{ + const uint32_t index = 0; + uintptr_t *v = bpf_map_lookup_elem(&ip, &index); + + return !(v && *v == PT_REGS_IP(&data->regs)); +} + +char _license[] SEC("license") = "GPL";
On Mon, Dec 4, 2023 at 12:14 PM Kyle Huey me@kylehuey.com wrote:
The test sets a hardware breakpoint and uses a bpf program to suppress the I/O availability signal if the ip matches the expected value.
Signed-off-by: Kyle Huey khuey@kylehuey.com
.../selftests/bpf/prog_tests/perf_skip.c | 95 +++++++++++++++++++ .../selftests/bpf/progs/test_perf_skip.c | 23 +++++ 2 files changed, 118 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/perf_skip.c create mode 100644 tools/testing/selftests/bpf/progs/test_perf_skip.c
diff --git a/tools/testing/selftests/bpf/prog_tests/perf_skip.c b/tools/testing/selftests/bpf/prog_tests/perf_skip.c new file mode 100644 index 000000000000..b269a31669b7 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/perf_skip.c @@ -0,0 +1,95 @@ +// SPDX-License-Identifier: GPL-2.0 +#define _GNU_SOURCE +#include <test_progs.h> +#include "test_perf_skip.skel.h" +#include <linux/hw_breakpoint.h> +#include <sys/mman.h>
+#define BPF_OBJECT "test_perf_skip.bpf.o"
leftover?
+static void handle_sig(int) +{
ASSERT_OK(1, "perf event not skipped");+}
+static noinline int test_function(void) +{
please add
asm volatile ("");
here to prevent compiler from actually inlining at the call site
return 0;+}
+void serial_test_perf_skip(void) +{
sighandler_t previous;int duration = 0;struct test_perf_skip *skel = NULL;int map_fd = -1;long page_size = sysconf(_SC_PAGE_SIZE);uintptr_t *ip = NULL;int prog_fd = -1;struct perf_event_attr attr = {0};int perf_fd = -1;struct f_owner_ex owner;int err;previous = signal(SIGIO, handle_sig);skel = test_perf_skip__open_and_load();if (!ASSERT_OK_PTR(skel, "skel_load"))goto cleanup;prog_fd = bpf_program__fd(skel->progs.handler);if (!ASSERT_OK(prog_fd < 0, "bpf_program__fd"))goto cleanup;map_fd = bpf_map__fd(skel->maps.ip);if (!ASSERT_OK(map_fd < 0, "bpf_map__fd"))goto cleanup;ip = mmap(NULL, page_size, PROT_READ | PROT_WRITE, MAP_SHARED, map_fd, 0);if (!ASSERT_OK_PTR(ip, "mmap bpf map"))goto cleanup;*ip = (uintptr_t)test_function;attr.type = PERF_TYPE_BREAKPOINT;attr.size = sizeof(attr);attr.bp_type = HW_BREAKPOINT_X;attr.bp_addr = (uintptr_t)test_function;attr.bp_len = sizeof(long);attr.sample_period = 1;attr.sample_type = PERF_SAMPLE_IP;attr.pinned = 1;attr.exclude_kernel = 1;attr.exclude_hv = 1;attr.precise_ip = 3;perf_fd = syscall(__NR_perf_event_open, &attr, 0, -1, -1, 0);if (CHECK(perf_fd < 0, "perf_event_open", "err %d\n", perf_fd))
please don't use CHECK() macro, stick to ASSERT_xxx()
also, we are going to run all this on different hardware and VMs, see how we skip tests if hardware support is not there. See test__skip usage in prog_tests/perf_branches.c, as one example
goto cleanup;err = fcntl(perf_fd, F_SETFL, O_ASYNC);
I assume this is what will send SIGIO, right? Can you add a small comment explicitly saying this?
if (!ASSERT_OK(err, "fcntl(F_SETFL, O_ASYNC)"))goto cleanup;owner.type = F_OWNER_TID;owner.pid = gettid();err = fcntl(perf_fd, F_SETOWN_EX, &owner);if (!ASSERT_OK(err, "fcntl(F_SETOWN_EX)"))goto cleanup;err = ioctl(perf_fd, PERF_EVENT_IOC_SET_BPF, prog_fd);if (!ASSERT_OK(err, "ioctl(PERF_EVENT_IOC_SET_BPF)"))goto cleanup;
we have a better way to do this, please use bpf_program__attach_perf_event() instead
test_function();+cleanup:
if (perf_fd >= 0)close(perf_fd);if (ip)munmap(ip, page_size);if (skel)test_perf_skip__destroy(skel);signal(SIGIO, previous);+} diff --git a/tools/testing/selftests/bpf/progs/test_perf_skip.c b/tools/testing/selftests/bpf/progs/test_perf_skip.c new file mode 100644 index 000000000000..ef01a9161afe --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_perf_skip.c @@ -0,0 +1,23 @@ +// SPDX-License-Identifier: GPL-2.0 +#include "vmlinux.h" +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h>
+struct {
__uint(type, BPF_MAP_TYPE_ARRAY);__uint(max_entries, 1);__uint(map_flags, BPF_F_MMAPABLE);__type(key, uint32_t);__type(value, uintptr_t);+} ip SEC(".maps");
please use global variable:
__u64 ip;
and then access it from user-space side through skeleton
skel->bss.ip = &test_function;
+SEC("perf_event") +int handler(struct bpf_perf_event_data *data) +{
const uint32_t index = 0;uintptr_t *v = bpf_map_lookup_elem(&ip, &index);return !(v && *v == PT_REGS_IP(&data->regs));
and so we the above global var suggestion this will be just:
return ip == PT_REGS_IP(&data->regs);
+}
+char _license[] SEC("license") = "GPL";
2.34.1
On Mon, Dec 4, 2023 at 2:14 PM Andrii Nakryiko andrii.nakryiko@gmail.com wrote:
On Mon, Dec 4, 2023 at 12:14 PM Kyle Huey me@kylehuey.com wrote:
The test sets a hardware breakpoint and uses a bpf program to suppress the I/O availability signal if the ip matches the expected value.
Signed-off-by: Kyle Huey khuey@kylehuey.com
.../selftests/bpf/prog_tests/perf_skip.c | 95 +++++++++++++++++++ .../selftests/bpf/progs/test_perf_skip.c | 23 +++++ 2 files changed, 118 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/perf_skip.c create mode 100644 tools/testing/selftests/bpf/progs/test_perf_skip.c
diff --git a/tools/testing/selftests/bpf/prog_tests/perf_skip.c b/tools/testing/selftests/bpf/prog_tests/perf_skip.c new file mode 100644 index 000000000000..b269a31669b7 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/perf_skip.c @@ -0,0 +1,95 @@ +// SPDX-License-Identifier: GPL-2.0 +#define _GNU_SOURCE +#include <test_progs.h> +#include "test_perf_skip.skel.h" +#include <linux/hw_breakpoint.h> +#include <sys/mman.h>
+#define BPF_OBJECT "test_perf_skip.bpf.o"
leftover?
Indeed. Fixed.
+static void handle_sig(int) +{
ASSERT_OK(1, "perf event not skipped");+}
+static noinline int test_function(void) +{
please add
asm volatile ("");
here to prevent compiler from actually inlining at the call site
Ok.
return 0;+}
+void serial_test_perf_skip(void) +{
sighandler_t previous;int duration = 0;struct test_perf_skip *skel = NULL;int map_fd = -1;long page_size = sysconf(_SC_PAGE_SIZE);uintptr_t *ip = NULL;int prog_fd = -1;struct perf_event_attr attr = {0};int perf_fd = -1;struct f_owner_ex owner;int err;previous = signal(SIGIO, handle_sig);skel = test_perf_skip__open_and_load();if (!ASSERT_OK_PTR(skel, "skel_load"))goto cleanup;prog_fd = bpf_program__fd(skel->progs.handler);if (!ASSERT_OK(prog_fd < 0, "bpf_program__fd"))goto cleanup;map_fd = bpf_map__fd(skel->maps.ip);if (!ASSERT_OK(map_fd < 0, "bpf_map__fd"))goto cleanup;ip = mmap(NULL, page_size, PROT_READ | PROT_WRITE, MAP_SHARED, map_fd, 0);if (!ASSERT_OK_PTR(ip, "mmap bpf map"))goto cleanup;*ip = (uintptr_t)test_function;attr.type = PERF_TYPE_BREAKPOINT;attr.size = sizeof(attr);attr.bp_type = HW_BREAKPOINT_X;attr.bp_addr = (uintptr_t)test_function;attr.bp_len = sizeof(long);attr.sample_period = 1;attr.sample_type = PERF_SAMPLE_IP;attr.pinned = 1;attr.exclude_kernel = 1;attr.exclude_hv = 1;attr.precise_ip = 3;perf_fd = syscall(__NR_perf_event_open, &attr, 0, -1, -1, 0);if (CHECK(perf_fd < 0, "perf_event_open", "err %d\n", perf_fd))please don't use CHECK() macro, stick to ASSERT_xxx()
Done.
also, we are going to run all this on different hardware and VMs, see how we skip tests if hardware support is not there. See test__skip usage in prog_tests/perf_branches.c, as one example
Hmm I suppose it should be conditioned on CONFIG_HAVE_HW_BREAKPOINT.
goto cleanup;err = fcntl(perf_fd, F_SETFL, O_ASYNC);I assume this is what will send SIGIO, right? Can you add a small comment explicitly saying this?
Done.
if (!ASSERT_OK(err, "fcntl(F_SETFL, O_ASYNC)"))goto cleanup;owner.type = F_OWNER_TID;owner.pid = gettid();err = fcntl(perf_fd, F_SETOWN_EX, &owner);if (!ASSERT_OK(err, "fcntl(F_SETOWN_EX)"))goto cleanup;err = ioctl(perf_fd, PERF_EVENT_IOC_SET_BPF, prog_fd);if (!ASSERT_OK(err, "ioctl(PERF_EVENT_IOC_SET_BPF)"))goto cleanup;we have a better way to do this, please use bpf_program__attach_perf_event() instead
Done.
test_function();+cleanup:
if (perf_fd >= 0)close(perf_fd);if (ip)munmap(ip, page_size);if (skel)test_perf_skip__destroy(skel);signal(SIGIO, previous);+} diff --git a/tools/testing/selftests/bpf/progs/test_perf_skip.c b/tools/testing/selftests/bpf/progs/test_perf_skip.c new file mode 100644 index 000000000000..ef01a9161afe --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_perf_skip.c @@ -0,0 +1,23 @@ +// SPDX-License-Identifier: GPL-2.0 +#include "vmlinux.h" +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h>
+struct {
__uint(type, BPF_MAP_TYPE_ARRAY);__uint(max_entries, 1);__uint(map_flags, BPF_F_MMAPABLE);__type(key, uint32_t);__type(value, uintptr_t);+} ip SEC(".maps");
please use global variable:
__u64 ip;
and then access it from user-space side through skeleton
skel->bss.ip = &test_function;
Done.
+SEC("perf_event") +int handler(struct bpf_perf_event_data *data) +{
const uint32_t index = 0;uintptr_t *v = bpf_map_lookup_elem(&ip, &index);return !(v && *v == PT_REGS_IP(&data->regs));and so we the above global var suggestion this will be just:
return ip == PT_REGS_IP(&data->regs);
+}
+char _license[] SEC("license") = "GPL";
2.34.1
- Kyle
On Mon, Dec 04, 2023 at 12:14:06PM -0800, Kyle Huey wrote:
The test sets a hardware breakpoint and uses a bpf program to suppress the I/O availability signal if the ip matches the expected value.
Signed-off-by: Kyle Huey khuey@kylehuey.com
.../selftests/bpf/prog_tests/perf_skip.c | 95 +++++++++++++++++++ .../selftests/bpf/progs/test_perf_skip.c | 23 +++++ 2 files changed, 118 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/perf_skip.c create mode 100644 tools/testing/selftests/bpf/progs/test_perf_skip.c
diff --git a/tools/testing/selftests/bpf/prog_tests/perf_skip.c b/tools/testing/selftests/bpf/prog_tests/perf_skip.c new file mode 100644 index 000000000000..b269a31669b7 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/perf_skip.c @@ -0,0 +1,95 @@ +// SPDX-License-Identifier: GPL-2.0 +#define _GNU_SOURCE +#include <test_progs.h> +#include "test_perf_skip.skel.h" +#include <linux/hw_breakpoint.h> +#include <sys/mman.h>
+#define BPF_OBJECT "test_perf_skip.bpf.o"
+static void handle_sig(int) +{
- ASSERT_OK(1, "perf event not skipped");
+}
+static noinline int test_function(void) +{
- return 0;
+}
+void serial_test_perf_skip(void)
does it need to be serial?
jirka
On 12/4/23 3:14 PM, Kyle Huey wrote:
The test sets a hardware breakpoint and uses a bpf program to suppress the I/O availability signal if the ip matches the expected value.
Signed-off-by: Kyle Huey khuey@kylehuey.com
.../selftests/bpf/prog_tests/perf_skip.c | 95 +++++++++++++++++++ .../selftests/bpf/progs/test_perf_skip.c | 23 +++++ 2 files changed, 118 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/perf_skip.c create mode 100644 tools/testing/selftests/bpf/progs/test_perf_skip.c
diff --git a/tools/testing/selftests/bpf/prog_tests/perf_skip.c b/tools/testing/selftests/bpf/prog_tests/perf_skip.c new file mode 100644 index 000000000000..b269a31669b7 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/perf_skip.c @@ -0,0 +1,95 @@ +// SPDX-License-Identifier: GPL-2.0 +#define _GNU_SOURCE +#include <test_progs.h> +#include "test_perf_skip.skel.h" +#include <linux/hw_breakpoint.h> +#include <sys/mman.h>
+#define BPF_OBJECT "test_perf_skip.bpf.o"
+static void handle_sig(int)
I hit a warning here: home/yhs/work/bpf-next/tools/testing/selftests/bpf/prog_tests/perf_skip.c:10:27: error: omitting the parameter name in a function definition is a C23 extension [-Werror,-Wc23-extensions] 10 | static void handle_sig(int) |
Add a parameter and marked as unused can resolve the issue.
#define __always_unused __attribute__((__unused__))
static void handle_sig(int unused __always_unused) { ASSERT_OK(1, "perf event not skipped"); }
+{
- ASSERT_OK(1, "perf event not skipped");
+}
+static noinline int test_function(void) +{
- return 0;
+}
+void serial_test_perf_skip(void) +{
- sighandler_t previous;
- int duration = 0;
- struct test_perf_skip *skel = NULL;
- int map_fd = -1;
- long page_size = sysconf(_SC_PAGE_SIZE);
- uintptr_t *ip = NULL;
- int prog_fd = -1;
- struct perf_event_attr attr = {0};
- int perf_fd = -1;
- struct f_owner_ex owner;
- int err;
- previous = signal(SIGIO, handle_sig);
- skel = test_perf_skip__open_and_load();
- if (!ASSERT_OK_PTR(skel, "skel_load"))
goto cleanup;- prog_fd = bpf_program__fd(skel->progs.handler);
- if (!ASSERT_OK(prog_fd < 0, "bpf_program__fd"))
goto cleanup;- map_fd = bpf_map__fd(skel->maps.ip);
- if (!ASSERT_OK(map_fd < 0, "bpf_map__fd"))
goto cleanup;- ip = mmap(NULL, page_size, PROT_READ | PROT_WRITE, MAP_SHARED, map_fd, 0);
- if (!ASSERT_OK_PTR(ip, "mmap bpf map"))
goto cleanup;- *ip = (uintptr_t)test_function;
- attr.type = PERF_TYPE_BREAKPOINT;
- attr.size = sizeof(attr);
- attr.bp_type = HW_BREAKPOINT_X;
- attr.bp_addr = (uintptr_t)test_function;
- attr.bp_len = sizeof(long);
- attr.sample_period = 1;
- attr.sample_type = PERF_SAMPLE_IP;
- attr.pinned = 1;
- attr.exclude_kernel = 1;
- attr.exclude_hv = 1;
- attr.precise_ip = 3;
- perf_fd = syscall(__NR_perf_event_open, &attr, 0, -1, -1, 0);
- if (CHECK(perf_fd < 0, "perf_event_open", "err %d\n", perf_fd))
goto cleanup;- err = fcntl(perf_fd, F_SETFL, O_ASYNC);
- if (!ASSERT_OK(err, "fcntl(F_SETFL, O_ASYNC)"))
goto cleanup;- owner.type = F_OWNER_TID;
- owner.pid = gettid();
I hit a compilation failure here:
/home/yhs/work/bpf-next/tools/testing/selftests/bpf/prog_tests/perf_skip.c:75:14: error: call to undeclared function 'gettid'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] 75 | owner.pid = gettid(); | ^
If you looked at some other examples, the common usage is do 'syscall(SYS_gettid)'. So the following patch should fix the compilation error:
#include <sys/syscall.h> ... owner.pid = syscall(SYS_gettid); ...
- err = fcntl(perf_fd, F_SETOWN_EX, &owner);
- if (!ASSERT_OK(err, "fcntl(F_SETOWN_EX)"))
goto cleanup;- err = ioctl(perf_fd, PERF_EVENT_IOC_SET_BPF, prog_fd);
- if (!ASSERT_OK(err, "ioctl(PERF_EVENT_IOC_SET_BPF)"))
goto cleanup;- test_function();
As Andrii has mentioned in previous comments, we will have issue is RELEASE version of selftest is built RELEASE=1 make ...
See https://lore.kernel.org/bpf/20231127050342.1945270-1-yonghong.song@linux.dev
+cleanup:
- if (perf_fd >= 0)
close(perf_fd);- if (ip)
munmap(ip, page_size);- if (skel)
test_perf_skip__destroy(skel);- signal(SIGIO, previous);
+} diff --git a/tools/testing/selftests/bpf/progs/test_perf_skip.c b/tools/testing/selftests/bpf/progs/test_perf_skip.c new file mode 100644 index 000000000000..ef01a9161afe --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_perf_skip.c @@ -0,0 +1,23 @@ +// SPDX-License-Identifier: GPL-2.0 +#include "vmlinux.h" +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h>
+struct {
- __uint(type, BPF_MAP_TYPE_ARRAY);
- __uint(max_entries, 1);
- __uint(map_flags, BPF_F_MMAPABLE);
- __type(key, uint32_t);
- __type(value, uintptr_t);
+} ip SEC(".maps");
+SEC("perf_event") +int handler(struct bpf_perf_event_data *data) +{
- const uint32_t index = 0;
- uintptr_t *v = bpf_map_lookup_elem(&ip, &index);
- return !(v && *v == PT_REGS_IP(&data->regs));
+}
+char _license[] SEC("license") = "GPL";
On Tue, Dec 5, 2023 at 8:54 AM Yonghong Song yonghong.song@linux.dev wrote:
On 12/4/23 3:14 PM, Kyle Huey wrote:
The test sets a hardware breakpoint and uses a bpf program to suppress the I/O availability signal if the ip matches the expected value.
Signed-off-by: Kyle Huey khuey@kylehuey.com
.../selftests/bpf/prog_tests/perf_skip.c | 95 +++++++++++++++++++ .../selftests/bpf/progs/test_perf_skip.c | 23 +++++ 2 files changed, 118 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/perf_skip.c create mode 100644 tools/testing/selftests/bpf/progs/test_perf_skip.c
diff --git a/tools/testing/selftests/bpf/prog_tests/perf_skip.c b/tools/testing/selftests/bpf/prog_tests/perf_skip.c new file mode 100644 index 000000000000..b269a31669b7 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/perf_skip.c @@ -0,0 +1,95 @@ +// SPDX-License-Identifier: GPL-2.0 +#define _GNU_SOURCE +#include <test_progs.h> +#include "test_perf_skip.skel.h" +#include <linux/hw_breakpoint.h> +#include <sys/mman.h>
+#define BPF_OBJECT "test_perf_skip.bpf.o"
+static void handle_sig(int)
I hit a warning here: home/yhs/work/bpf-next/tools/testing/selftests/bpf/prog_tests/perf_skip.c:10:27: error: omitting the parameter name in a function definition is a C23 extension [-Werror,-Wc23-extensions]
Yeah, Meta's kernel-ci bot sent me off-list email about this one.
10 | static void handle_sig(int) |Add a parameter and marked as unused can resolve the issue.
#define __always_unused __attribute__((__unused__))
static void handle_sig(int unused __always_unused) { ASSERT_OK(1, "perf event not skipped"); }
+{
ASSERT_OK(1, "perf event not skipped");+}
+static noinline int test_function(void) +{
return 0;+}
+void serial_test_perf_skip(void) +{
sighandler_t previous;int duration = 0;struct test_perf_skip *skel = NULL;int map_fd = -1;long page_size = sysconf(_SC_PAGE_SIZE);uintptr_t *ip = NULL;int prog_fd = -1;struct perf_event_attr attr = {0};int perf_fd = -1;struct f_owner_ex owner;int err;previous = signal(SIGIO, handle_sig);skel = test_perf_skip__open_and_load();if (!ASSERT_OK_PTR(skel, "skel_load"))goto cleanup;prog_fd = bpf_program__fd(skel->progs.handler);if (!ASSERT_OK(prog_fd < 0, "bpf_program__fd"))goto cleanup;map_fd = bpf_map__fd(skel->maps.ip);if (!ASSERT_OK(map_fd < 0, "bpf_map__fd"))goto cleanup;ip = mmap(NULL, page_size, PROT_READ | PROT_WRITE, MAP_SHARED, map_fd, 0);if (!ASSERT_OK_PTR(ip, "mmap bpf map"))goto cleanup;*ip = (uintptr_t)test_function;attr.type = PERF_TYPE_BREAKPOINT;attr.size = sizeof(attr);attr.bp_type = HW_BREAKPOINT_X;attr.bp_addr = (uintptr_t)test_function;attr.bp_len = sizeof(long);attr.sample_period = 1;attr.sample_type = PERF_SAMPLE_IP;attr.pinned = 1;attr.exclude_kernel = 1;attr.exclude_hv = 1;attr.precise_ip = 3;perf_fd = syscall(__NR_perf_event_open, &attr, 0, -1, -1, 0);if (CHECK(perf_fd < 0, "perf_event_open", "err %d\n", perf_fd))goto cleanup;err = fcntl(perf_fd, F_SETFL, O_ASYNC);if (!ASSERT_OK(err, "fcntl(F_SETFL, O_ASYNC)"))goto cleanup;owner.type = F_OWNER_TID;owner.pid = gettid();I hit a compilation failure here:
/home/yhs/work/bpf-next/tools/testing/selftests/bpf/prog_tests/perf_skip.c:75:14: error: call to undeclared function 'gettid'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] 75 | owner.pid = gettid(); | ^
If you looked at some other examples, the common usage is do 'syscall(SYS_gettid)'.
Not clear why this works for me but sure I'll change that.
So the following patch should fix the compilation error:
#include <sys/syscall.h> ... owner.pid = syscall(SYS_gettid); ...
err = fcntl(perf_fd, F_SETOWN_EX, &owner);if (!ASSERT_OK(err, "fcntl(F_SETOWN_EX)"))goto cleanup;err = ioctl(perf_fd, PERF_EVENT_IOC_SET_BPF, prog_fd);if (!ASSERT_OK(err, "ioctl(PERF_EVENT_IOC_SET_BPF)"))goto cleanup;test_function();As Andrii has mentioned in previous comments, we will have issue is RELEASE version of selftest is built RELEASE=1 make ...
See https://lore.kernel.org/bpf/20231127050342.1945270-1-yonghong.song@linux.dev
Not sure I follow this one. Are you saying adding asm volatile ("") in test_function() is *not* sufficient?
- Kyle
+cleanup:
if (perf_fd >= 0)close(perf_fd);if (ip)munmap(ip, page_size);if (skel)test_perf_skip__destroy(skel);signal(SIGIO, previous);+} diff --git a/tools/testing/selftests/bpf/progs/test_perf_skip.c b/tools/testing/selftests/bpf/progs/test_perf_skip.c new file mode 100644 index 000000000000..ef01a9161afe --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_perf_skip.c @@ -0,0 +1,23 @@ +// SPDX-License-Identifier: GPL-2.0 +#include "vmlinux.h" +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h>
+struct {
__uint(type, BPF_MAP_TYPE_ARRAY);__uint(max_entries, 1);__uint(map_flags, BPF_F_MMAPABLE);__type(key, uint32_t);__type(value, uintptr_t);+} ip SEC(".maps");
+SEC("perf_event") +int handler(struct bpf_perf_event_data *data) +{
const uint32_t index = 0;uintptr_t *v = bpf_map_lookup_elem(&ip, &index);return !(v && *v == PT_REGS_IP(&data->regs));+}
+char _license[] SEC("license") = "GPL";
linux-kselftest-mirror@lists.linaro.org
-
Andrii Nakryiko -
Jiri Olsa -
Kyle Huey -
Yonghong Song