selftests/bpf: Add test for map_ptr arithmetic

Change selftest map_ptr_kern.c with disabling inlining for
one of subtests, which will fail the test without previous
verifier change. Also added to verifier test for both
"map_ptr += scalar" and "scalar += map_ptr" arithmetic.

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200908175703.2463721-1-yhs@fb.com

Author: yonghong-song

tools/testing/selftests/bpf/progs/map_ptr_kern.c

@@ -82,6 +82,14 @@ static inline int check_default(struct bpf_map *indirect,
 	return 1;
 }
 
+static __noinline int
+check_default_noinline(struct bpf_map *indirect, struct bpf_map *direct)
+{
+	VERIFY(check(indirect, direct, sizeof(__u32), sizeof(__u32),
+		     MAX_ENTRIES));
+	return 1;
+}
+
 typedef struct {
 	int counter;
 } atomic_t;
@@ -107,7 +115,7 @@ static inline int check_hash(void)
 	struct bpf_map *map = (struct bpf_map *)&m_hash;
 	int i;
 
-	VERIFY(check_default(&hash->map, map));
+	VERIFY(check_default_noinline(&hash->map, map));
 
 	VERIFY(hash->n_buckets == MAX_ENTRIES);
 	VERIFY(hash->elem_size == 64);

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

@@ -60,3 +60,35 @@
 	.result = ACCEPT,
 	.retval = 1,
 },
+{
+	"bpf_map_ptr: r = 0, map_ptr = map_ptr + r",
+	.insns = {
+	BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+	BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+	BPF_MOV64_IMM(BPF_REG_0, 0),
+	BPF_LD_MAP_FD(BPF_REG_1, 0),
+	BPF_ALU64_REG(BPF_ADD, BPF_REG_1, BPF_REG_0),
+	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
+	BPF_MOV64_IMM(BPF_REG_0, 0),
+	BPF_EXIT_INSN(),
+	},
+	.fixup_map_hash_16b = { 4 },
+	.result = ACCEPT,
+},
+{
+	"bpf_map_ptr: r = 0, r = r + map_ptr",
+	.insns = {
+	BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+	BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+	BPF_MOV64_IMM(BPF_REG_1, 0),
+	BPF_LD_MAP_FD(BPF_REG_0, 0),
+	BPF_ALU64_REG(BPF_ADD, BPF_REG_1, BPF_REG_0),
+	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
+	BPF_MOV64_IMM(BPF_REG_0, 0),
+	BPF_EXIT_INSN(),
+	},
+	.fixup_map_hash_16b = { 4 },
+	.result = ACCEPT,
+},