selftests/bpf: Add callchain_stackid

// SPDX-License-Identifier: GPL-2.0

// Copyright (c) 2020 Facebook

#define _GNU_SOURCE

#include <pthread.h>

#include <sched.h>

#include <test_progs.h>

#include "perf_event_stackmap.skel.h"

#ifndef noinline

#define noinline __attribute__((noinline))

#endif

noinline int func_1(void)

{

	static int val = 1;

	val += 1;

	usleep(100);

	return val;

}

noinline int func_2(void)

{

	return func_1();

}

noinline int func_3(void)

{

	return func_2();

}

noinline int func_4(void)

{

	return func_3();

}

noinline int func_5(void)

{

	return func_4();

}

noinline int func_6(void)

{

	int i, val = 1;

	for (i = 0; i < 100; i++)

		val += func_5();

	return val;

}

void test_perf_event_stackmap(void)

{

	struct perf_event_attr attr = {

		/* .type = PERF_TYPE_SOFTWARE, */

		.type = PERF_TYPE_HARDWARE,

		.config = PERF_COUNT_HW_CPU_CYCLES,

		.precise_ip = 2,

		.sample_type = PERF_SAMPLE_IP | PERF_SAMPLE_BRANCH_STACK |

			PERF_SAMPLE_CALLCHAIN,

		.branch_sample_type = PERF_SAMPLE_BRANCH_USER |

			PERF_SAMPLE_BRANCH_NO_FLAGS |

			PERF_SAMPLE_BRANCH_NO_CYCLES |

			PERF_SAMPLE_BRANCH_CALL_STACK,

		.sample_period = 5000,

		.size = sizeof(struct perf_event_attr),

	};

	struct perf_event_stackmap *skel;

	__u32 duration = 0;

	cpu_set_t cpu_set;

	int pmu_fd, err;

	skel = perf_event_stackmap__open();

	if (CHECK(!skel, "skel_open", "skeleton open failed\n"))

		return;

	err = perf_event_stackmap__load(skel);

	if (CHECK(err, "skel_load", "skeleton load failed: %d\n", err))

		goto cleanup;

	CPU_ZERO(&cpu_set);

	CPU_SET(0, &cpu_set);

	err = pthread_setaffinity_np(pthread_self(), sizeof(cpu_set), &cpu_set);

	if (CHECK(err, "set_affinity", "err %d, errno %d\n", err, errno))

		goto cleanup;

	pmu_fd = syscall(__NR_perf_event_open, &attr, -1 /* pid */,

			 0 /* cpu 0 */, -1 /* group id */,

			 0 /* flags */);

	if (pmu_fd < 0) {

		printf("%s:SKIP:cpu doesn't support the event\n", __func__);

		test__skip();

		goto cleanup;

	}

	skel->links.oncpu = bpf_program__attach_perf_event(skel->progs.oncpu,

							   pmu_fd);

	if (CHECK(IS_ERR(skel->links.oncpu), "attach_perf_event",

		  "err %ld\n", PTR_ERR(skel->links.oncpu))) {

		close(pmu_fd);

		goto cleanup;

	}

	/* create kernel and user stack traces for testing */

	func_6();

	CHECK(skel->data->stackid_kernel != 2, "get_stackid_kernel", "failed\n");

	CHECK(skel->data->stackid_user != 2, "get_stackid_user", "failed\n");

	CHECK(skel->data->stack_kernel != 2, "get_stack_kernel", "failed\n");

	CHECK(skel->data->stack_user != 2, "get_stack_user", "failed\n");

cleanup:

	perf_event_stackmap__destroy(skel);

}

// SPDX-License-Identifier: GPL-2.0

// Copyright (c) 2020 Facebook

#include "vmlinux.h"

#include <bpf/bpf_helpers.h>

#ifndef PERF_MAX_STACK_DEPTH

#define PERF_MAX_STACK_DEPTH         127

#endif

typedef __u64 stack_trace_t[PERF_MAX_STACK_DEPTH];

struct {

	__uint(type, BPF_MAP_TYPE_STACK_TRACE);

	__uint(max_entries, 16384);

	__uint(key_size, sizeof(__u32));

	__uint(value_size, sizeof(stack_trace_t));

} stackmap SEC(".maps");

struct {

	__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);

	__uint(max_entries, 1);

	__type(key, __u32);

	__type(value, stack_trace_t);

} stackdata_map SEC(".maps");

long stackid_kernel = 1;

long stackid_user = 1;

long stack_kernel = 1;

long stack_user = 1;

SEC("perf_event")

int oncpu(void *ctx)

{

	stack_trace_t *trace;

	__u32 key = 0;

	long val;

	val = bpf_get_stackid(ctx, &stackmap, 0);

	if (val > 0)

		stackid_kernel = 2;

	val = bpf_get_stackid(ctx, &stackmap, BPF_F_USER_STACK);

	if (val > 0)

		stackid_user = 2;

	trace = bpf_map_lookup_elem(&stackdata_map, &key);

	if (!trace)

		return 0;

	val = bpf_get_stack(ctx, trace, sizeof(stack_trace_t), 0);

	if (val > 0)

		stack_kernel = 2;

	val = bpf_get_stack(ctx, trace, sizeof(stack_trace_t), BPF_F_USER_STACK);

	if (val > 0)

		stack_user = 2;

	return 0;

}

char LICENSE[] SEC("license") = "GPL";