Re: [PATCH 01/14] bpf/tests: Add BPF_JMP32 test cases

Yonghong Song <yhs@xxxxxx> · Wed, 28 Jul 2021 15:31:28 -0700

On 7/28/21 10:04 AM, Johan Almbladh wrote:
An eBPF JIT may implement JMP32 operations in a different way than JMP,
especially on 32-bit architectures. This patch adds a series of tests
for JMP32 operations, mainly for testing JITs.

Signed-off-by: Johan Almbladh <johan.almbladh@xxxxxxxxxxxxxxxxx>

LGTM with a few minor comments below.

Acked-by: Yonghong Song <yhs@xxxxxx>

---
  lib/test_bpf.c | 511 +++++++++++++++++++++++++++++++++++++++++++++++++
  1 file changed, 511 insertions(+)

diff --git a/lib/test_bpf.c b/lib/test_bpf.c
index f6d5d30d01bf..bfac033db590 100644
--- a/lib/test_bpf.c
+++ b/lib/test_bpf.c
@@ -4398,6 +4398,517 @@ static struct bpf_test tests[] = {
  		{ { 0, 4134 } },
  		.fill_helper = bpf_fill_stxdw,
  	},
+	/* BPF_JMP32 | BPF_JEQ | BPF_K */
+	{
+		"JMP32_JEQ_K: Small immediate",
+		.u.insns_int = {
+			BPF_ALU32_IMM(BPF_MOV, R0, 123),
+			BPF_JMP32_IMM(BPF_JEQ, R0, 321, 1),
+			BPF_JMP32_IMM(BPF_JEQ, R0, 123, 1),
+			BPF_ALU32_IMM(BPF_MOV, R0, 0),
+			BPF_EXIT_INSN(),
+		},
+		INTERNAL,
+		{ },
+		{ { 0, 123 } }
+	},
[...]
+	/* BPF_JMP32 | BPF_JGT | BPF_X */
+	{
+		"JMP32_JGT_X",
+		.u.insns_int = {
+			BPF_ALU32_IMM(BPF_MOV, R0, 0xfffffffe),
+			BPF_ALU32_IMM(BPF_MOV, R1, 0xffffffff),
+			BPF_JMP32_REG(BPF_JGT, R0, R1, 1),

Maybe change the offset from 1 to 2? Otherwise, this may jump to
  BPF_JMP32_REG(BPF_JGT, R0, R1, 1)
which will just do the same comparison and jump to BTT_EXIT_INSN()
which will also have R0 = 0xfffffffe at the end.

+			BPF_ALU32_IMM(BPF_MOV, R1, 0xfffffffd),
+			BPF_JMP32_REG(BPF_JGT, R0, R1, 1),
+			BPF_ALU32_IMM(BPF_MOV, R0, 0),
+			BPF_EXIT_INSN(),
+		},
+		INTERNAL,
+		{ },
+		{ { 0, 0xfffffffe } }
+	},
+	/* BPF_JMP32 | BPF_JGE | BPF_K */
+	{
+		"JMP32_JGE_K: Small immediate",
+		.u.insns_int = {
+			BPF_ALU32_IMM(BPF_MOV, R0, 123),
+			BPF_JMP32_IMM(BPF_JGE, R0, 124, 1),
+			BPF_JMP32_IMM(BPF_JGE, R0, 123, 1),
+			BPF_ALU32_IMM(BPF_MOV, R0, 0),
+			BPF_EXIT_INSN(),
+		},
+		INTERNAL,
+		{ },
+		{ { 0, 123 } }
+	},
+	{
+		"JMP32_JGE_K: Large immediate",
+		.u.insns_int = {
+			BPF_ALU32_IMM(BPF_MOV, R0, 0xfffffffe),
+			BPF_JMP32_IMM(BPF_JGE, R0, 0xffffffff, 1),
+			BPF_JMP32_IMM(BPF_JGE, R0, 0xfffffffe, 1),
+			BPF_ALU32_IMM(BPF_MOV, R0, 0),
+			BPF_EXIT_INSN(),
+		},
+		INTERNAL,
+		{ },
+		{ { 0, 0xfffffffe } }
+	},
+	/* BPF_JMP32 | BPF_JGE | BPF_X */
+	{
+		"JMP32_JGE_X",
+		.u.insns_int = {
+			BPF_ALU32_IMM(BPF_MOV, R0, 0xfffffffe),
+			BPF_ALU32_IMM(BPF_MOV, R1, 0xffffffff),
+			BPF_JMP32_REG(BPF_JGE, R0, R1, 1),

ditto, change offset 1 to 2?

+			BPF_ALU32_IMM(BPF_MOV, R1, 0xfffffffe),
+			BPF_JMP32_REG(BPF_JGE, R0, R1, 1),
+			BPF_ALU32_IMM(BPF_MOV, R0, 0),
+			BPF_EXIT_INSN(),
+		},
+		INTERNAL,
+		{ },
+		{ { 0, 0xfffffffe } }
+	},
+	/* BPF_JMP32 | BPF_JLT | BPF_K */
+	{
+		"JMP32_JLT_K: Small immediate",
+		.u.insns_int = {
+			BPF_ALU32_IMM(BPF_MOV, R0, 123),
+			BPF_JMP32_IMM(BPF_JLT, R0, 123, 1),
+			BPF_JMP32_IMM(BPF_JLT, R0, 124, 1),
+			BPF_ALU32_IMM(BPF_MOV, R0, 0),
+			BPF_EXIT_INSN(),
+		},
+		INTERNAL,
+		{ },
+		{ { 0, 123 } }
+	},
+	{
+		"JMP32_JLT_K: Large immediate",
+		.u.insns_int = {
+			BPF_ALU32_IMM(BPF_MOV, R0, 0xfffffffe),
+			BPF_JMP32_IMM(BPF_JLT, R0, 0xfffffffd, 1),
+			BPF_JMP32_IMM(BPF_JLT, R0, 0xffffffff, 1),
+			BPF_ALU32_IMM(BPF_MOV, R0, 0),
+			BPF_EXIT_INSN(),
+		},
+		INTERNAL,
+		{ },
+		{ { 0, 0xfffffffe } }
+	},
+	/* BPF_JMP32 | BPF_JLT | BPF_X */
+	{
+		"JMP32_JLT_X",
+		.u.insns_int = {
+			BPF_ALU32_IMM(BPF_MOV, R0, 0xfffffffe),
+			BPF_ALU32_IMM(BPF_MOV, R1, 0xfffffffd),
+			BPF_JMP32_REG(BPF_JLT, R0, R1, 1),

ditto.

+			BPF_ALU32_IMM(BPF_MOV, R1, 0xffffffff),
+			BPF_JMP32_REG(BPF_JLT, R0, R1, 1),
+			BPF_ALU32_IMM(BPF_MOV, R0, 0),
+			BPF_EXIT_INSN(),
+		},
+		INTERNAL,
+		{ },
+		{ { 0, 0xfffffffe } }
+	},
+	/* BPF_JMP32 | BPF_JLE | BPF_K */
+	{
+		"JMP32_JLE_K: Small immediate",
+		.u.insns_int = {
+			BPF_ALU32_IMM(BPF_MOV, R0, 123),
+			BPF_JMP32_IMM(BPF_JLE, R0, 122, 1),
+			BPF_JMP32_IMM(BPF_JLE, R0, 123, 1),
+			BPF_ALU32_IMM(BPF_MOV, R0, 0),
+			BPF_EXIT_INSN(),
+		},
+		INTERNAL,
+		{ },
+		{ { 0, 123 } }
+	},
+	{
+		"JMP32_JLE_K: Large immediate",
+		.u.insns_int = {
+			BPF_ALU32_IMM(BPF_MOV, R0, 0xfffffffe),
+			BPF_JMP32_IMM(BPF_JLE, R0, 0xfffffffd, 1),
+			BPF_JMP32_IMM(BPF_JLE, R0, 0xfffffffe, 1),
+			BPF_ALU32_IMM(BPF_MOV, R0, 0),
+			BPF_EXIT_INSN(),
+		},
+		INTERNAL,
+		{ },
+		{ { 0, 0xfffffffe } }
+	},
+	/* BPF_JMP32 | BPF_JLE | BPF_X */
+	{
+		"JMP32_JLE_X",
+		.u.insns_int = {
+			BPF_ALU32_IMM(BPF_MOV, R0, 0xfffffffe),
+			BPF_ALU32_IMM(BPF_MOV, R1, 0xfffffffd),
+			BPF_JMP32_REG(BPF_JLE, R0, R1, 1),
+			BPF_ALU32_IMM(BPF_MOV, R1, 0xfffffffe),
+			BPF_JMP32_REG(BPF_JLE, R0, R1, 1),

ditto

+			BPF_ALU32_IMM(BPF_MOV, R0, 0),
+			BPF_EXIT_INSN(),
+		},
+		INTERNAL,
+		{ },
+		{ { 0, 0xfffffffe } }
+	},
+	/* BPF_JMP32 | BPF_JSGT | BPF_K */
+	{
+		"JMP32_JSGT_K: Small immediate",
+		.u.insns_int = {
+			BPF_ALU32_IMM(BPF_MOV, R0, -123),
+			BPF_JMP32_IMM(BPF_JSGT, R0, -123, 1),
+			BPF_JMP32_IMM(BPF_JSGT, R0, -124, 1),
+			BPF_ALU32_IMM(BPF_MOV, R0, 0),
+			BPF_EXIT_INSN(),
+		},
+		INTERNAL,
+		{ },
+		{ { 0, -123 } }
+	},
+	{
+		"JMP32_JSGT_K: Large immediate",
+		.u.insns_int = {
+			BPF_ALU32_IMM(BPF_MOV, R0, -12345678),
+			BPF_JMP32_IMM(BPF_JSGT, R0, -12345678, 1),
+			BPF_JMP32_IMM(BPF_JSGT, R0, -12345679, 1),
+			BPF_ALU32_IMM(BPF_MOV, R0, 0),
+			BPF_EXIT_INSN(),
+		},
+		INTERNAL,
+		{ },
+		{ { 0, -12345678 } }
+	},
+	/* BPF_JMP32 | BPF_JSGT | BPF_X */
+	{
+		"JMP32_JSGT_X",
+		.u.insns_int = {
+			BPF_ALU32_IMM(BPF_MOV, R0, -12345678),
+			BPF_ALU32_IMM(BPF_MOV, R1, -12345678),
+			BPF_JMP32_REG(BPF_JSGT, R0, R1, 1),

ditto

+			BPF_ALU32_IMM(BPF_MOV, R1, -12345679),
+			BPF_JMP32_REG(BPF_JSGT, R0, R1, 1),
+			BPF_ALU32_IMM(BPF_MOV, R0, 0),
+			BPF_EXIT_INSN(),
+		},
+		INTERNAL,
+		{ },
+		{ { 0, -12345678 } }
+	},
+	/* BPF_JMP32 | BPF_JSGE | BPF_K */
+	{
+		"JMP32_JSGE_K: Small immediate",
+		.u.insns_int = {
+			BPF_ALU32_IMM(BPF_MOV, R0, -123),
+			BPF_JMP32_IMM(BPF_JSGE, R0, -122, 1),
+			BPF_JMP32_IMM(BPF_JSGE, R0, -123, 1),
+			BPF_ALU32_IMM(BPF_MOV, R0, 0),
+			BPF_EXIT_INSN(),
+		},
+		INTERNAL,
+		{ },
+		{ { 0, -123 } }
+	},
+	{
+		"JMP32_JSGE_K: Large immediate",
+		.u.insns_int = {
+			BPF_ALU32_IMM(BPF_MOV, R0, -12345678),
+			BPF_JMP32_IMM(BPF_JSGE, R0, -12345677, 1),
+			BPF_JMP32_IMM(BPF_JSGE, R0, -12345678, 1),
+			BPF_ALU32_IMM(BPF_MOV, R0, 0),
+			BPF_EXIT_INSN(),
+		},
+		INTERNAL,
+		{ },
+		{ { 0, -12345678 } }
+	},
+	/* BPF_JMP32 | BPF_JSGE | BPF_X */
+	{
+		"JMP32_JSGE_X",
+		.u.insns_int = {
+			BPF_ALU32_IMM(BPF_MOV, R0, -12345678),
+			BPF_ALU32_IMM(BPF_MOV, R1, -12345677),
+			BPF_JMP32_REG(BPF_JSGE, R0, R1, 1),

ditto

+			BPF_ALU32_IMM(BPF_MOV, R1, -12345678),
+			BPF_JMP32_REG(BPF_JSGE, R0, R1, 1),
+			BPF_ALU32_IMM(BPF_MOV, R0, 0),
+			BPF_EXIT_INSN(),
+		},
+		INTERNAL,
+		{ },
+		{ { 0, -12345678 } }
+	},
+	/* BPF_JMP32 | BPF_JSLT | BPF_K */
+	{
+		"JMP32_JSLT_K: Small immediate",
+		.u.insns_int = {
+			BPF_ALU32_IMM(BPF_MOV, R0, -123),
+			BPF_JMP32_IMM(BPF_JSLT, R0, -123, 1),
+			BPF_JMP32_IMM(BPF_JSLT, R0, -122, 1),
+			BPF_ALU32_IMM(BPF_MOV, R0, 0),
+			BPF_EXIT_INSN(),
+		},
+		INTERNAL,
+		{ },
+		{ { 0, -123 } }
+	},
+	{
+		"JMP32_JSLT_K: Large immediate",
+		.u.insns_int = {
+			BPF_ALU32_IMM(BPF_MOV, R0, -12345678),
+			BPF_JMP32_IMM(BPF_JSLT, R0, -12345678, 1),
+			BPF_JMP32_IMM(BPF_JSLT, R0, -12345677, 1),
+			BPF_ALU32_IMM(BPF_MOV, R0, 0),
+			BPF_EXIT_INSN(),
+		},
+		INTERNAL,
+		{ },
+		{ { 0, -12345678 } }
+	},
+	/* BPF_JMP32 | BPF_JSLT | BPF_X */
+	{
+		"JMP32_JSLT_X",
+		.u.insns_int = {
+			BPF_ALU32_IMM(BPF_MOV, R0, -12345678),
+			BPF_ALU32_IMM(BPF_MOV, R1, -12345678),
+			BPF_JMP32_REG(BPF_JSLT, R0, R1, 1),

ditto

+			BPF_ALU32_IMM(BPF_MOV, R1, -12345677),
+			BPF_JMP32_REG(BPF_JSLT, R0, R1, 1),
+			BPF_ALU32_IMM(BPF_MOV, R0, 0),
+			BPF_EXIT_INSN(),
+		},
+		INTERNAL,
+		{ },
+		{ { 0, -12345678 } }
+	},
+	/* BPF_JMP32 | BPF_JSLE | BPF_K */
+	{
+		"JMP32_JSLE_K: Small immediate",
+		.u.insns_int = {
+			BPF_ALU32_IMM(BPF_MOV, R0, -123),
+			BPF_JMP32_IMM(BPF_JSLE, R0, -124, 1),
+			BPF_JMP32_IMM(BPF_JSLE, R0, -123, 1),
+			BPF_ALU32_IMM(BPF_MOV, R0, 0),
+			BPF_EXIT_INSN(),
+		},
+		INTERNAL,
+		{ },
+		{ { 0, -123 } }
+	},
+	{
+		"JMP32_JSLE_K: Large immediate",
+		.u.insns_int = {
+			BPF_ALU32_IMM(BPF_MOV, R0, -12345678),
+			BPF_JMP32_IMM(BPF_JSLE, R0, -12345679, 1),
+			BPF_JMP32_IMM(BPF_JSLE, R0, -12345678, 1),
+			BPF_ALU32_IMM(BPF_MOV, R0, 0),
+			BPF_EXIT_INSN(),
+		},
+		INTERNAL,
+		{ },
+		{ { 0, -12345678 } }
+	},
+	/* BPF_JMP32 | BPF_JSLE | BPF_K */
+	{
+		"JMP32_JSLE_X",
+		.u.insns_int = {
+			BPF_ALU32_IMM(BPF_MOV, R0, -12345678),
+			BPF_ALU32_IMM(BPF_MOV, R1, -12345679),
+			BPF_JMP32_REG(BPF_JSLE, R0, R1, 1),

ditto

+			BPF_ALU32_IMM(BPF_MOV, R1, -12345678),
+			BPF_JMP32_REG(BPF_JSLE, R0, R1, 1),
+			BPF_ALU32_IMM(BPF_MOV, R0, 0),
+			BPF_EXIT_INSN(),
+		},
+		INTERNAL,
+		{ },
+		{ { 0, -12345678 } }
+	},
  	/* BPF_JMP | BPF_EXIT */
  	{
  		"JMP_EXIT",







