From: Xu Kuohai <xukuohai@huawei.com>
Date: Mon, 21 Mar 2022 11:28:52 -0400
Subject: bpf, tests: Add load store test case for tail call
Patch-mainline: v5.19-rc1
Git-commit: 38608ee7b6907830f157818d81f7b2393d49c808
References: jsc#PED-1377

Add test case to enusre that the caller and callee's fp offsets are
correct during tail call (mainly asserting for arm64 JIT).

Tested on both big-endian and little-endian arm64 qemu, result:

 test_bpf: Summary: 1026 PASSED, 0 FAILED, [1014/1014 JIT'ed]
 test_bpf: test_tail_calls: Summary: 10 PASSED, 0 FAILED, [10/10 JIT'ed]
 test_bpf: test_skb_segment: Summary: 2 PASSED, 0 FAILED

Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220321152852.2334294-6-xukuohai@huawei.com
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
---
 lib/test_bpf.c |   30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

--- a/lib/test_bpf.c
+++ b/lib/test_bpf.c
@@ -14951,6 +14951,36 @@ static struct tail_call_test tail_call_t
 		.result = 10,
 	},
 	{
+		"Tail call load/store leaf",
+		.insns = {
+			BPF_ALU64_IMM(BPF_MOV, R1, 1),
+			BPF_ALU64_IMM(BPF_MOV, R2, 2),
+			BPF_ALU64_REG(BPF_MOV, R3, BPF_REG_FP),
+			BPF_STX_MEM(BPF_DW, R3, R1, -8),
+			BPF_STX_MEM(BPF_DW, R3, R2, -16),
+			BPF_LDX_MEM(BPF_DW, R0, BPF_REG_FP, -8),
+			BPF_JMP_REG(BPF_JNE, R0, R1, 3),
+			BPF_LDX_MEM(BPF_DW, R0, BPF_REG_FP, -16),
+			BPF_JMP_REG(BPF_JNE, R0, R2, 1),
+			BPF_ALU64_IMM(BPF_MOV, R0, 0),
+			BPF_EXIT_INSN(),
+		},
+		.result = 0,
+		.stack_depth = 32,
+	},
+	{
+		"Tail call load/store",
+		.insns = {
+			BPF_ALU64_IMM(BPF_MOV, R0, 3),
+			BPF_STX_MEM(BPF_DW, BPF_REG_FP, R0, -8),
+			TAIL_CALL(-1),
+			BPF_ALU64_IMM(BPF_MOV, R0, -1),
+			BPF_EXIT_INSN(),
+		},
+		.result = 0,
+		.stack_depth = 16,
+	},
+	{
 		"Tail call error path, max count reached",
 		.insns = {
 			BPF_LDX_MEM(BPF_W, R2, R1, 0),