[PATCH bpf-next v2 8/9] tools/bpf: add a verifier test case for bpf_get_stack helper and ARSH

[Yonghong Song]

The test_verifier already has a few ARSH test cases.
This patch adds a new test case which takes advantage of newly
improved verifier behavior for bpf_get_stack and ARSH.

Signed-off-by: Yonghong Song <y...@fb.com>
---
 tools/testing/selftests/bpf/test_verifier.c | 45 +++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)

diff --git a/tools/testing/selftests/bpf/test_verifier.c 
b/tools/testing/selftests/bpf/test_verifier.c
index 3e7718b..cd595ba 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -11423,6 +11423,51 @@ static struct bpf_test tests[] = {
                .errstr = "BPF_XADD stores into R2 packet",
                .prog_type = BPF_PROG_TYPE_XDP,
        },
+       {
+               "bpf_get_stack return R0 within range",
+               .insns = {
+                       BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
+                       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_LD_MAP_FD(BPF_REG_1, 0),
+                       BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+                                    BPF_FUNC_map_lookup_elem),
+                       BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 28),
+                       BPF_MOV64_REG(BPF_REG_7, BPF_REG_0),
+                       BPF_MOV64_IMM(BPF_REG_9, sizeof(struct test_val)),
+                       BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
+                       BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),
+                       BPF_MOV64_IMM(BPF_REG_3, sizeof(struct test_val)),
+                       BPF_MOV64_IMM(BPF_REG_4, 256),
+                       BPF_EMIT_CALL(BPF_FUNC_get_stack),
+                       BPF_MOV64_IMM(BPF_REG_1, 0),
+                       BPF_MOV64_REG(BPF_REG_8, BPF_REG_0),
+                       BPF_ALU64_IMM(BPF_LSH, BPF_REG_8, 32),
+                       BPF_ALU64_IMM(BPF_ARSH, BPF_REG_8, 32),
+                       BPF_JMP_REG(BPF_JSLT, BPF_REG_1, BPF_REG_8, 16),
+                       BPF_ALU64_REG(BPF_SUB, BPF_REG_9, BPF_REG_8),
+                       BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),
+                       BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_8),
+                       BPF_MOV64_REG(BPF_REG_1, BPF_REG_9),
+                       BPF_ALU64_IMM(BPF_LSH, BPF_REG_1, 32),
+                       BPF_ALU64_IMM(BPF_ARSH, BPF_REG_1, 32),
+                       BPF_MOV64_REG(BPF_REG_3, BPF_REG_2),
+                       BPF_ALU64_REG(BPF_ADD, BPF_REG_3, BPF_REG_1),
+                       BPF_MOV64_REG(BPF_REG_1, BPF_REG_7),
+                       BPF_MOV64_IMM(BPF_REG_5, sizeof(struct test_val)),
+                       BPF_ALU64_REG(BPF_ADD, BPF_REG_1, BPF_REG_5),
+                       BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_1, 4),
+                       BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
+                       BPF_MOV64_REG(BPF_REG_3, BPF_REG_9),
+                       BPF_MOV64_IMM(BPF_REG_4, 0),
+                       BPF_EMIT_CALL(BPF_FUNC_get_stack),
+                       BPF_EXIT_INSN(),
+               },
+               .fixup_map2 = { 4 },
+               .result = ACCEPT,
+               .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+       },
 };
 
 static int probe_filter_length(const struct bpf_insn *fp)
-- 
2.9.5