selftests/bpf: verifier precise tests

Use BPF_F_TEST_STATE_FREQ flag to check that precision
tracking works as expected by comparing every step it takes.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

tools/testing/selftests/bpf/verifier/precise.c

@@ -0,0 +1,117 @@
+{
+	"precise: test 1",
+	.insns = {
+	BPF_MOV64_IMM(BPF_REG_0, 1),
+	BPF_LD_MAP_FD(BPF_REG_6, 0),
+	BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
+	BPF_MOV64_REG(BPF_REG_2, BPF_REG_FP),
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+	BPF_ST_MEM(BPF_DW, BPF_REG_FP, -8, 0),
+	BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
+	BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
+	BPF_EXIT_INSN(),
+
+	BPF_MOV64_REG(BPF_REG_9, BPF_REG_0),
+
+	BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
+	BPF_MOV64_REG(BPF_REG_2, BPF_REG_FP),
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+	BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
+	BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
+	BPF_EXIT_INSN(),
+
+	BPF_MOV64_REG(BPF_REG_8, BPF_REG_0),
+
+	BPF_ALU64_REG(BPF_SUB, BPF_REG_9, BPF_REG_8), /* map_value_ptr -= map_value_ptr */
+	BPF_MOV64_REG(BPF_REG_2, BPF_REG_9),
+	BPF_JMP_IMM(BPF_JLT, BPF_REG_2, 8, 1),
+	BPF_EXIT_INSN(),
+
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, 1), /* R2=inv(umin=1, umax=8) */
+	BPF_MOV64_REG(BPF_REG_1, BPF_REG_FP),
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+	BPF_MOV64_IMM(BPF_REG_3, 0),
+	BPF_EMIT_CALL(BPF_FUNC_probe_read),
+	BPF_EXIT_INSN(),
+	},
+	.prog_type = BPF_PROG_TYPE_TRACEPOINT,
+	.fixup_map_array_48b = { 1 },
+	.result = VERBOSE_ACCEPT,
+	.errstr =
+	"26: (85) call bpf_probe_read#4\
+	last_idx 26 first_idx 20\
+	regs=4 stack=0 before 25\
+	regs=4 stack=0 before 24\
+	regs=4 stack=0 before 23\
+	regs=4 stack=0 before 22\
+	regs=4 stack=0 before 20\
+	parent didn't have regs=4 stack=0 marks\
+	last_idx 19 first_idx 10\
+	regs=4 stack=0 before 19\
+	regs=200 stack=0 before 18\
+	regs=300 stack=0 before 17\
+	regs=201 stack=0 before 15\
+	regs=201 stack=0 before 14\
+	regs=200 stack=0 before 13\
+	regs=200 stack=0 before 12\
+	regs=200 stack=0 before 11\
+	regs=200 stack=0 before 10\
+	parent already had regs=0 stack=0 marks",
+},
+{
+	"precise: test 2",
+	.insns = {
+	BPF_MOV64_IMM(BPF_REG_0, 1),
+	BPF_LD_MAP_FD(BPF_REG_6, 0),
+	BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
+	BPF_MOV64_REG(BPF_REG_2, BPF_REG_FP),
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+	BPF_ST_MEM(BPF_DW, BPF_REG_FP, -8, 0),
+	BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
+	BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
+	BPF_EXIT_INSN(),
+
+	BPF_MOV64_REG(BPF_REG_9, BPF_REG_0),
+
+	BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
+	BPF_MOV64_REG(BPF_REG_2, BPF_REG_FP),
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+	BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
+	BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
+	BPF_EXIT_INSN(),
+
+	BPF_MOV64_REG(BPF_REG_8, BPF_REG_0),
+
+	BPF_ALU64_REG(BPF_SUB, BPF_REG_9, BPF_REG_8), /* map_value_ptr -= map_value_ptr */
+	BPF_MOV64_REG(BPF_REG_2, BPF_REG_9),
+	BPF_JMP_IMM(BPF_JLT, BPF_REG_2, 8, 1),
+	BPF_EXIT_INSN(),
+
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, 1), /* R2=inv(umin=1, umax=8) */
+	BPF_MOV64_REG(BPF_REG_1, BPF_REG_FP),
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+	BPF_MOV64_IMM(BPF_REG_3, 0),
+	BPF_EMIT_CALL(BPF_FUNC_probe_read),
+	BPF_EXIT_INSN(),
+	},
+	.prog_type = BPF_PROG_TYPE_TRACEPOINT,
+	.fixup_map_array_48b = { 1 },
+	.result = VERBOSE_ACCEPT,
+	.flags = BPF_F_TEST_STATE_FREQ,
+	.errstr =
+	"26: (85) call bpf_probe_read#4\
+	last_idx 26 first_idx 22\
+	regs=4 stack=0 before 25\
+	regs=4 stack=0 before 24\
+	regs=4 stack=0 before 23\
+	regs=4 stack=0 before 22\
+	parent didn't have regs=4 stack=0 marks\
+	last_idx 20 first_idx 20\
+	regs=4 stack=0 before 20\
+	parent didn't have regs=4 stack=0 marks\
+	last_idx 19 first_idx 17\
+	regs=4 stack=0 before 19\
+	regs=200 stack=0 before 18\
+	regs=300 stack=0 before 17\
+	parent already had regs=0 stack=0 marks",
+},