[PATCH v7 05/10] test/bpf: add test for large shift

There were multiple bugs with immediate values in shift instructions.
The code was not masking as required by RFC.

Add new tests that cover these instructions.

Signed-off-by: Stephen Hemminger <[email protected]>
Acked-by: Marat Khalili <[email protected]>
Acked-by: Konstantin Ananyev <[email protected]>
---
 app/test/test_bpf.c | 59 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)

diff --git a/app/test/test_bpf.c b/app/test/test_bpf.c
index f4286bcefe..413d47357f 100644
--- a/app/test/test_bpf.c
+++ b/app/test/test_bpf.c
@@ -2012,6 +2012,51 @@ test_div1_check(uint64_t rc, const void *arg)
 	return cmp_res(__func__, 0, rc, dve.out, dvt->out, sizeof(dve.out));
 }
 
+/*
+ * Shift counts are masked to the operand width (RFC 9669: 0x3f for 64-bit,
+ * 0x1f for 32-bit). Counts >= 128 also exercise the x86 imm_size() path that
+ * used to desync the stream, and the arm64 UBFM/SBFM immediate encoding.
+ */
+static const struct ebpf_insn test_shift_big_imm_prog[] = {
+	{
+		.code = (EBPF_ALU64 | EBPF_MOV | BPF_K),
+		.dst_reg = EBPF_REG_0,
+		.imm = 1
+	},
+	{
+		.code = (EBPF_ALU64 | BPF_LSH | BPF_K),
+		.dst_reg = EBPF_REG_0,
+		.imm = 191
+	},
+	{
+		.code = (EBPF_ALU64 | EBPF_ARSH | BPF_K),
+		.dst_reg = EBPF_REG_0,
+		.imm = 200
+	},
+	{
+		.code = (EBPF_ALU64 | BPF_RSH | BPF_K),
+		.dst_reg = EBPF_REG_0,
+		.imm = 130
+	},
+	{
+		.code = (BPF_JMP | EBPF_EXIT)
+	},
+};
+
+static void
+test_shift_big_imm_prepare(void *arg)
+{
+	memset(arg, 0, sizeof(struct dummy_offset));
+}
+
+static int
+test_shift_big_imm_check(uint64_t rc, const void *arg)
+{
+	uint64_t expect = 0x3FE0000000000000ULL;
+
+	return cmp_res(__func__, expect, rc, arg, arg, 0);
+}
+
 /* call test-cases */
 static const struct ebpf_insn test_call1_prog[] = {
 
@@ -3480,6 +3525,20 @@ static const struct bpf_test tests[] = {
 		.prepare = test_mul1_prepare,
 		.check_result = test_div1_check,
 	},
+	{
+		.name = "test_shift_big_imm",
+		.arg_sz = sizeof(struct dummy_offset),
+		.prm = {
+			.ins = test_shift_big_imm_prog,
+			.nb_ins = RTE_DIM(test_shift_big_imm_prog),
+			.prog_arg = {
+				.type = RTE_BPF_ARG_PTR,
+				.size = sizeof(struct dummy_offset),
+			},
+		},
+		.prepare = test_shift_big_imm_prepare,
+		.check_result = test_shift_big_imm_check,
+	},
 	{
 		.name = "test_call1",
 		.arg_sz = sizeof(struct dummy_offset),
-- 
2.53.0