bpf: Fix tailcall cases in test_bpf

Since f663a03 ("bpf, x64: Remove tail call detection"),
tail_call_reachable won't be detected in x86 JIT. And, tail_call_reachable
is provided by verifier.

Therefore, in test_bpf, the tail_call_reachable must be provided in test
cases before running.

Fix and test:

[  174.828662] test_bpf: #0 Tail call leaf jited:1 170 PASS
[  174.829574] test_bpf: #1 Tail call 2 jited:1 244 PASS
[  174.830363] test_bpf: #2 Tail call 3 jited:1 296 PASS
[  174.830924] test_bpf: #3 Tail call 4 jited:1 719 PASS
[  174.831863] test_bpf: #4 Tail call load/store leaf jited:1 197 PASS
[  174.832240] test_bpf: #5 Tail call load/store jited:1 326 PASS
[  174.832240] test_bpf: #6 Tail call error path, max count reached jited:1 2214 PASS
[  174.835713] test_bpf: #7 Tail call count preserved across function calls jited:1 609751 PASS
[  175.446098] test_bpf: #8 Tail call error path, NULL target jited:1 472 PASS
[  175.447597] test_bpf: #9 Tail call error path, index out of range jited:1 206 PASS
[  175.448833] test_bpf: test_tail_calls: Summary: 10 PASSED, 0 FAILED, [10/10 JIT'ed]

Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202406251415.c51865bc-oliver.sang@intel.com
Fixes: f663a03 ("bpf, x64: Remove tail call detection")
Signed-off-by: Leon Hwang <hffilwlqm@gmail.com>
Link: https://lore.kernel.org/r/20240625145351.40072-1-hffilwlqm@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Author: Asphaltt

lib/test_bpf.c

@@ -15198,6 +15198,7 @@ struct tail_call_test {
 	int flags;
 	int result;
 	int stack_depth;
+	bool has_tail_call;
 };
 
 /* Flags that can be passed to tail call test cases */
@@ -15273,6 +15274,7 @@ static struct tail_call_test tail_call_tests[] = {
 			BPF_EXIT_INSN(),
 		},
 		.result = 3,
+		.has_tail_call = true,
 	},
 	{
 		"Tail call 3",
@@ -15283,6 +15285,7 @@ static struct tail_call_test tail_call_tests[] = {
 			BPF_EXIT_INSN(),
 		},
 		.result = 6,
+		.has_tail_call = true,
 	},
 	{
 		"Tail call 4",
@@ -15293,6 +15296,7 @@ static struct tail_call_test tail_call_tests[] = {
 			BPF_EXIT_INSN(),
 		},
 		.result = 10,
+		.has_tail_call = true,
 	},
 	{
 		"Tail call load/store leaf",
@@ -15323,6 +15327,7 @@ static struct tail_call_test tail_call_tests[] = {
 		},
 		.result = 0,
 		.stack_depth = 16,
+		.has_tail_call = true,
 	},
 	{
 		"Tail call error path, max count reached",
@@ -15335,6 +15340,7 @@ static struct tail_call_test tail_call_tests[] = {
 		},
 		.flags = FLAG_NEED_STATE | FLAG_RESULT_IN_STATE,
 		.result = (MAX_TAIL_CALL_CNT + 1) * MAX_TESTRUNS,
+		.has_tail_call = true,
 	},
 	{
 		"Tail call count preserved across function calls",
@@ -15357,6 +15363,7 @@ static struct tail_call_test tail_call_tests[] = {
 		.stack_depth = 8,
 		.flags = FLAG_NEED_STATE | FLAG_RESULT_IN_STATE,
 		.result = (MAX_TAIL_CALL_CNT + 1) * MAX_TESTRUNS,
+		.has_tail_call = true,
 	},
 	{
 		"Tail call error path, NULL target",
@@ -15369,6 +15376,7 @@ static struct tail_call_test tail_call_tests[] = {
 		},
 		.flags = FLAG_NEED_STATE | FLAG_RESULT_IN_STATE,
 		.result = MAX_TESTRUNS,
+		.has_tail_call = true,
 	},
 	{
 		"Tail call error path, index out of range",
@@ -15381,6 +15389,7 @@ static struct tail_call_test tail_call_tests[] = {
 		},
 		.flags = FLAG_NEED_STATE | FLAG_RESULT_IN_STATE,
 		.result = MAX_TESTRUNS,
+		.has_tail_call = true,
 	},
 };
 
@@ -15430,6 +15439,7 @@ static __init int prepare_tail_call_tests(struct bpf_array **pprogs)
 		fp->len = len;
 		fp->type = BPF_PROG_TYPE_SOCKET_FILTER;
 		fp->aux->stack_depth = test->stack_depth;
+		fp->aux->tail_call_reachable = test->has_tail_call;
 		memcpy(fp->insnsi, test->insns, len * sizeof(struct bpf_insn));
 
 		/* Relocate runtime tail call offsets and addresses */