[bpf-next v2 09/10] selftests/bpf: Add tests for bpf_prog_test_run for perf events progs

Krzesimir Nowak
2019-06-25T19:43:11Z

The tests check if ctx and data are correctly prepared from ctx_in and
data_in, so accessing the ctx and using the bpf_perf_prog_read_value
work as expected.

Signed-off-by: Krzesimir Nowak <krzesimir@kinvolk.io>
---
tools/testing/selftests/bpf/test_verifier.c | 48 ++++++++++
.../selftests/bpf/verifier/perf_event_run.c | 93 +++++++++++++++++++
2 files changed, 141 insertions(+)
create mode 100644 tools/testing/selftests/bpf/verifier/perf_event_run.c

diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index 05bad54f481f..6fa962014b64 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -293,6 +293,54 @@ static void bpf_fill_scale(struct bpf_test *self)
}
}

+static void bpf_fill_perf_event_test_run_check(struct bpf_test *self)
+{
+ compiletime_assert(
+ sizeof(struct bpf_perf_event_data) <= TEST_CTX_LEN,
+ "buffer for ctx is too short to fit struct bpf_perf_event_data");
+ compiletime_assert(
+ sizeof(struct bpf_perf_event_value) <= TEST_DATA_LEN,
+ "buffer for data is too short to fit struct bpf_perf_event_value");
+
+ struct bpf_perf_event_data ctx = {
+ .regs = (bpf_user_pt_regs_t) {
+ .r15 = 1,
+ .r14 = 2,
+ .r13 = 3,
+ .r12 = 4,
+ .rbp = 5,
+ .rbx = 6,
+ .r11 = 7,
+ .r10 = 8,
+ .r9 = 9,
+ .r8 = 10,
+ .rax = 11,
+ .rcx = 12,
+ .rdx = 13,
+ .rsi = 14,
+ .rdi = 15,
+ .orig_rax = 16,
+ .rip = 17,
+ .cs = 18,
+ .eflags = 19,
+ .rsp = 20,
+ .ss = 21,
+ },
+ .sample_period = 1,
+ .addr = 2,
+ };
+ struct bpf_perf_event_value data = {
+ .counter = 1,
+ .enabled = 2,
+ .running = 3,
+ };
+
+ memcpy(self->ctx, &ctx, sizeof(ctx));
+ memcpy(self->data, &data, sizeof(data));
+ free(self->fill_insns);
+ self->fill_insns = NULL;
+}
+
/* BPF_SK_LOOKUP contains 13 instructions, if you need to fix up maps */
#define BPF_SK_LOOKUP(func) \
/* struct bpf_sock_tuple tuple = {} */ \
diff --git a/tools/testing/selftests/bpf/verifier/perf_event_run.c b/tools/testing/selftests/bpf/verifier/perf_event_run.c
new file mode 100644
index 000000000000..d451932a6fc0
--- /dev/null
+++ b/tools/testing/selftests/bpf/verifier/perf_event_run.c
@@ -0,0 +1,93 @@
+#define PER_LOAD_AND_CHECK_PTREG(PT_REG_FIELD, VALUE) \
+ PER_LOAD_AND_CHECK_CTX(offsetof(bpf_user_pt_regs_t, PT_REG_FIELD), VALUE)
+#define PER_LOAD_AND_CHECK_EVENT(PED_FIELD, VALUE) \
+ PER_LOAD_AND_CHECK_CTX(offsetof(struct bpf_perf_event_data, PED_FIELD), VALUE)
+#define PER_LOAD_AND_CHECK_CTX(OFFSET, VALUE) \
+ PER_LOAD_AND_CHECK_64(BPF_REG_4, BPF_REG_1, OFFSET, VALUE)
+#define PER_LOAD_AND_CHECK_VALUE(PEV_FIELD, VALUE) \
+ PER_LOAD_AND_CHECK_64(BPF_REG_7, BPF_REG_6, offsetof(struct bpf_perf_event_value, PEV_FIELD), VALUE)
+#define PER_LOAD_AND_CHECK_64(DST, SRC, OFFSET, VALUE) \
+ BPF_LDX_MEM(BPF_DW, DST, SRC, OFFSET), \
+ BPF_JMP_IMM(BPF_JEQ, DST, VALUE, 2), \
+ BPF_MOV64_IMM(BPF_REG_0, VALUE), \
+ BPF_EXIT_INSN()
+
+{
+ "check if regs contain expected values",
+ .insns = {
+ PER_LOAD_AND_CHECK_PTREG(r15, 1),
+ PER_LOAD_AND_CHECK_PTREG(r14, 2),
+ PER_LOAD_AND_CHECK_PTREG(r13, 3),
+ PER_LOAD_AND_CHECK_PTREG(r12, 4),
+ PER_LOAD_AND_CHECK_PTREG(rbp, 5),
+ PER_LOAD_AND_CHECK_PTREG(rbx, 6),
+ PER_LOAD_AND_CHECK_PTREG(r11, 7),
+ PER_LOAD_AND_CHECK_PTREG(r10, 8),
+ PER_LOAD_AND_CHECK_PTREG(r9, 9),
+ PER_LOAD_AND_CHECK_PTREG(r8, 10),
+ PER_LOAD_AND_CHECK_PTREG(rax, 11),
+ PER_LOAD_AND_CHECK_PTREG(rcx, 12),
+ PER_LOAD_AND_CHECK_PTREG(rdx, 13),
+ PER_LOAD_AND_CHECK_PTREG(rsi, 14),
+ PER_LOAD_AND_CHECK_PTREG(rdi, 15),
+ PER_LOAD_AND_CHECK_PTREG(orig_rax, 16),
+ PER_LOAD_AND_CHECK_PTREG(rip, 17),
+ PER_LOAD_AND_CHECK_PTREG(cs, 18),
+ PER_LOAD_AND_CHECK_PTREG(eflags, 19),
+ PER_LOAD_AND_CHECK_PTREG(rsp, 20),
+ PER_LOAD_AND_CHECK_PTREG(ss, 21),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .prog_type = BPF_PROG_TYPE_PERF_EVENT,
+ .ctx_len = sizeof(struct bpf_perf_event_data),
+ .data_len = sizeof(struct bpf_perf_event_value),
+ .fill_helper = bpf_fill_perf_event_test_run_check,
+},
+{
+ "check if sample period and addr contain expected values",
+ .insns = {
+ PER_LOAD_AND_CHECK_EVENT(sample_period, 1),
+ PER_LOAD_AND_CHECK_EVENT(addr, 2),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .prog_type = BPF_PROG_TYPE_PERF_EVENT,
+ .ctx_len = sizeof(struct bpf_perf_event_data),
+ .data_len = sizeof(struct bpf_perf_event_value),
+ .fill_helper = bpf_fill_perf_event_test_run_check,
+},
+{
+ "check if bpf_perf_prog_read_value returns expected data",
+ .insns = {
+ // allocate space for a struct bpf_perf_event_value
+ BPF_MOV64_REG(BPF_REG_6, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, -(int)sizeof(struct bpf_perf_event_value)),
+ // prepare parameters for bpf_perf_prog_read_value(ctx, struct bpf_perf_event_value*, u32)
+ // BPF_REG_1 already contains the context
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_6),
+ BPF_MOV64_IMM(BPF_REG_3, sizeof(struct bpf_perf_event_value)),
+ BPF_EMIT_CALL(BPF_FUNC_perf_prog_read_value),
+ // check the return value
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 1),
+ BPF_EXIT_INSN(),
+ // check if the fields match the expected values
+ PER_LOAD_AND_CHECK_VALUE(counter, 1),
+ PER_LOAD_AND_CHECK_VALUE(enabled, 2),
+ PER_LOAD_AND_CHECK_VALUE(running, 3),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .prog_type = BPF_PROG_TYPE_PERF_EVENT,
+ .ctx_len = sizeof(struct bpf_perf_event_data),
+ .data_len = sizeof(struct bpf_perf_event_value),
+ .fill_helper = bpf_fill_perf_event_test_run_check,
+},
+#undef PER_LOAD_AND_CHECK_64
+#undef PER_LOAD_AND_CHECK_VALUE
+#undef PER_LOAD_AND_CHECK_CTX
+#undef PER_LOAD_AND_CHECK_EVENT
+#undef PER_LOAD_AND_CHECK_PTREG
--
2.20.1