[PATCH bpf-next v2 09/13] bpf/tests: Add JMP tests with small offsets

From: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Date: 2021-09-07 22:24:05
Also in: bpf
Reply to: Johan Almbladh, 2021-09-07

This patch adds a set of tests for JMP to verify that the JITed jump
offset is calculated correctly. We pretend that the verifier has inserted
any zero extensions to make the jump-over operations JIT to one
instruction each, in order to control the exact JITed jump offset.

Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
---
 lib/test_bpf.c | 71 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 71 insertions(+)

diff --git a/lib/test_bpf.c b/lib/test_bpf.c
index 26f7c244c78a..7286cf347b95 100644
--- a/lib/test_bpf.c
+++ b/lib/test_bpf.c

@@ -10709,6 +10709,77 @@ static struct bpf_test tests[] = {
 		.fill_helper = bpf_fill_jmp32_jsle_reg,
 		.nr_testruns = NR_PATTERN_RUNS,
 	},
+	/* Short relative jumps */
+	{
+		"Short relative jump: offset=0",
+		.u.insns_int = {
+			BPF_ALU64_IMM(BPF_MOV, R0, 0),
+			BPF_JMP_IMM(BPF_JEQ, R0, 0, 0),
+			BPF_EXIT_INSN(),
+			BPF_ALU32_IMM(BPF_MOV, R0, -1),
+		},
+		INTERNAL | FLAG_NO_DATA | FLAG_VERIFIER_ZEXT,
+		{ },
+		{ { 0, 0 } },
+	},
+	{
+		"Short relative jump: offset=1",
+		.u.insns_int = {
+			BPF_ALU64_IMM(BPF_MOV, R0, 0),
+			BPF_JMP_IMM(BPF_JEQ, R0, 0, 1),
+			BPF_ALU32_IMM(BPF_ADD, R0, 1),
+			BPF_EXIT_INSN(),
+			BPF_ALU32_IMM(BPF_MOV, R0, -1),
+		},
+		INTERNAL | FLAG_NO_DATA | FLAG_VERIFIER_ZEXT,
+		{ },
+		{ { 0, 0 } },
+	},
+	{
+		"Short relative jump: offset=2",
+		.u.insns_int = {
+			BPF_ALU64_IMM(BPF_MOV, R0, 0),
+			BPF_JMP_IMM(BPF_JEQ, R0, 0, 2),
+			BPF_ALU32_IMM(BPF_ADD, R0, 1),
+			BPF_ALU32_IMM(BPF_ADD, R0, 1),
+			BPF_EXIT_INSN(),
+			BPF_ALU32_IMM(BPF_MOV, R0, -1),
+		},
+		INTERNAL | FLAG_NO_DATA | FLAG_VERIFIER_ZEXT,
+		{ },
+		{ { 0, 0 } },
+	},
+	{
+		"Short relative jump: offset=3",
+		.u.insns_int = {
+			BPF_ALU64_IMM(BPF_MOV, R0, 0),
+			BPF_JMP_IMM(BPF_JEQ, R0, 0, 3),
+			BPF_ALU32_IMM(BPF_ADD, R0, 1),
+			BPF_ALU32_IMM(BPF_ADD, R0, 1),
+			BPF_ALU32_IMM(BPF_ADD, R0, 1),
+			BPF_EXIT_INSN(),
+			BPF_ALU32_IMM(BPF_MOV, R0, -1),
+		},
+		INTERNAL | FLAG_NO_DATA | FLAG_VERIFIER_ZEXT,
+		{ },
+		{ { 0, 0 } },
+	},
+	{
+		"Short relative jump: offset=4",
+		.u.insns_int = {
+			BPF_ALU64_IMM(BPF_MOV, R0, 0),
+			BPF_JMP_IMM(BPF_JEQ, R0, 0, 4),
+			BPF_ALU32_IMM(BPF_ADD, R0, 1),
+			BPF_ALU32_IMM(BPF_ADD, R0, 1),
+			BPF_ALU32_IMM(BPF_ADD, R0, 1),
+			BPF_ALU32_IMM(BPF_ADD, R0, 1),
+			BPF_EXIT_INSN(),
+			BPF_ALU32_IMM(BPF_MOV, R0, -1),
+		},
+		INTERNAL | FLAG_NO_DATA | FLAG_VERIFIER_ZEXT,
+		{ },
+		{ { 0, 0 } },
+	},
 	/* Staggered jump sequences, immediate */
 	{
 		"Staggered jumps: JMP_JA",

-- 
2.25.1

[PATCH bpf-next v2 00/13] bpf/tests: Extend JIT test suite coverage · Johan Almbladh <johan.almbladh@anyfinetworks.com> · 2021-09-07
[PATCH bpf-next v2 03/13] bpf/tests: Add exhaustive tests of ALU shift values · Johan Almbladh <johan.almbladh@anyfinetworks.com> · 2021-09-07
[PATCH bpf-next v2 05/13] bpf/tests: Add exhaustive tests of JMP operand magnitudes · Johan Almbladh <johan.almbladh@anyfinetworks.com> · 2021-09-07
[PATCH bpf-next v2 01/13] bpf/tests: Allow different number of runs per test case · Johan Almbladh <johan.almbladh@anyfinetworks.com> · 2021-09-07
[PATCH bpf-next v2 02/13] bpf/tests: Reduce memory footprint of test suite · Johan Almbladh <johan.almbladh@anyfinetworks.com> · 2021-09-07
[PATCH bpf-next v2 04/13] bpf/tests: Add exhaustive tests of ALU operand magnitudes · Johan Almbladh <johan.almbladh@anyfinetworks.com> · 2021-09-07
[PATCH bpf-next v2 06/13] bpf/tests: Add staggered JMP and JMP32 tests · Johan Almbladh <johan.almbladh@anyfinetworks.com> · 2021-09-07
[PATCH bpf-next v2 07/13] bpf/tests: Add exhaustive test of LD_IMM64 immediate magnitudes · Johan Almbladh <johan.almbladh@anyfinetworks.com> · 2021-09-07
[PATCH bpf-next v2 08/13] bpf/tests: Add test case flag for verifier zero-extension · Johan Almbladh <johan.almbladh@anyfinetworks.com> · 2021-09-07
[PATCH bpf-next v2 09/13] bpf/tests: Add JMP tests with small offsets · Johan Almbladh <johan.almbladh@anyfinetworks.com> · 2021-09-07
[PATCH bpf-next v2 10/13] bpf/tests: Add JMP tests with degenerate conditional · Johan Almbladh <johan.almbladh@anyfinetworks.com> · 2021-09-07
[PATCH bpf-next v2 11/13] bpf/tests: Expand branch conversion JIT test · Johan Almbladh <johan.almbladh@anyfinetworks.com> · 2021-09-07
[PATCH bpf-next v2 12/13] bpf/tests: Add more BPF_END byte order conversion tests · Johan Almbladh <johan.almbladh@anyfinetworks.com> · 2021-09-07
[PATCH bpf-next v2 13/13] bpf/tests: Add tail call limit test with external function call · Johan Almbladh <johan.almbladh@anyfinetworks.com> · 2021-09-07
Re: [PATCH bpf-next v2 13/13] bpf/tests: Add tail call limit test with external function call · Ilya Leoshkevich <iii@linux.ibm.com> · 2021-09-08
Re: [PATCH bpf-next v2 13/13] bpf/tests: Add tail call limit test with external function call · Johan Almbladh <johan.almbladh@anyfinetworks.com> · 2021-09-08
Re: [PATCH bpf-next v2 13/13] bpf/tests: Add tail call limit test with external function call · Daniel Borkmann <daniel@iogearbox.net> · 2021-09-08
Re: [PATCH bpf-next v2 13/13] bpf/tests: Add tail call limit test with external function call · Johan Almbladh <johan.almbladh@anyfinetworks.com> · 2021-09-08
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