forked from Minki/linux
bpf, tests: Add tail call test suite
While BPF_CALL instructions were tested implicitly by the cBPF-to-eBPF translation, there has not been any tests for BPF_TAIL_CALL instructions. The new test suite includes tests for tail call chaining, tail call count tracking and error paths. It is mainly intended for JIT development and testing. Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20210809091829.810076-15-johan.almbladh@anyfinetworks.com
This commit is contained in:
Johan Almbladh
Daniel Borkmann
parent
6a3b24ca48
commit
874be05f52
248
lib/test_bpf.c
248
lib/test_bpf.c
@ -8989,8 +8989,248 @@ static __init int test_bpf(void)
|
||||
return err_cnt ? -EINVAL : 0;
|
||||
}
|
||||
|
||||
struct tail_call_test {
|
||||
const char *descr;
|
||||
struct bpf_insn insns[MAX_INSNS];
|
||||
int result;
|
||||
int stack_depth;
|
||||
};
|
||||
|
||||
/*
|
||||
* Magic marker used in test snippets for tail calls below.
|
||||
* BPF_LD/MOV to R2 and R2 with this immediate value is replaced
|
||||
* with the proper values by the test runner.
|
||||
*/
|
||||
#define TAIL_CALL_MARKER 0x7a11ca11
|
||||
|
||||
/* Special offset to indicate a NULL call target */
|
||||
#define TAIL_CALL_NULL 0x7fff
|
||||
|
||||
/* Special offset to indicate an out-of-range index */
|
||||
#define TAIL_CALL_INVALID 0x7ffe
|
||||
|
||||
#define TAIL_CALL(offset) \
|
||||
BPF_LD_IMM64(R2, TAIL_CALL_MARKER), \
|
||||
BPF_RAW_INSN(BPF_ALU | BPF_MOV | BPF_K, R3, 0, \
|
||||
offset, TAIL_CALL_MARKER), \
|
||||
BPF_JMP_IMM(BPF_TAIL_CALL, 0, 0, 0)
|
||||
|
||||
/*
|
||||
* Tail call tests. Each test case may call any other test in the table,
|
||||
* including itself, specified as a relative index offset from the calling
|
||||
* test. The index TAIL_CALL_NULL can be used to specify a NULL target
|
||||
* function to test the JIT error path. Similarly, the index TAIL_CALL_INVALID
|
||||
* results in a target index that is out of range.
|
||||
*/
|
||||
static struct tail_call_test tail_call_tests[] = {
|
||||
{
|
||||
"Tail call leaf",
|
||||
.insns = {
|
||||
BPF_ALU64_REG(BPF_MOV, R0, R1),
|
||||
BPF_ALU64_IMM(BPF_ADD, R0, 1),
|
||||
BPF_EXIT_INSN(),
|
||||
},
|
||||
.result = 1,
|
||||
},
|
||||
{
|
||||
"Tail call 2",
|
||||
.insns = {
|
||||
BPF_ALU64_IMM(BPF_ADD, R1, 2),
|
||||
TAIL_CALL(-1),
|
||||
BPF_ALU64_IMM(BPF_MOV, R0, -1),
|
||||
BPF_EXIT_INSN(),
|
||||
},
|
||||
.result = 3,
|
||||
},
|
||||
{
|
||||
"Tail call 3",
|
||||
.insns = {
|
||||
BPF_ALU64_IMM(BPF_ADD, R1, 3),
|
||||
TAIL_CALL(-1),
|
||||
BPF_ALU64_IMM(BPF_MOV, R0, -1),
|
||||
BPF_EXIT_INSN(),
|
||||
},
|
||||
.result = 6,
|
||||
},
|
||||
{
|
||||
"Tail call 4",
|
||||
.insns = {
|
||||
BPF_ALU64_IMM(BPF_ADD, R1, 4),
|
||||
TAIL_CALL(-1),
|
||||
BPF_ALU64_IMM(BPF_MOV, R0, -1),
|
||||
BPF_EXIT_INSN(),
|
||||
},
|
||||
.result = 10,
|
||||
},
|
||||
{
|
||||
"Tail call error path, max count reached",
|
||||
.insns = {
|
||||
BPF_ALU64_IMM(BPF_ADD, R1, 1),
|
||||
BPF_ALU64_REG(BPF_MOV, R0, R1),
|
||||
TAIL_CALL(0),
|
||||
BPF_EXIT_INSN(),
|
||||
},
|
||||
.result = MAX_TAIL_CALL_CNT + 1,
|
||||
},
|
||||
{
|
||||
"Tail call error path, NULL target",
|
||||
.insns = {
|
||||
BPF_ALU64_IMM(BPF_MOV, R0, -1),
|
||||
TAIL_CALL(TAIL_CALL_NULL),
|
||||
BPF_ALU64_IMM(BPF_MOV, R0, 1),
|
||||
BPF_EXIT_INSN(),
|
||||
},
|
||||
.result = 1,
|
||||
},
|
||||
{
|
||||
"Tail call error path, index out of range",
|
||||
.insns = {
|
||||
BPF_ALU64_IMM(BPF_MOV, R0, -1),
|
||||
TAIL_CALL(TAIL_CALL_INVALID),
|
||||
BPF_ALU64_IMM(BPF_MOV, R0, 1),
|
||||
BPF_EXIT_INSN(),
|
||||
},
|
||||
.result = 1,
|
||||
},
|
||||
};
|
||||
|
||||
static void __init destroy_tail_call_tests(struct bpf_array *progs)
|
||||
{
|
||||
int i;
|
||||
|
||||
for (i = 0; i < ARRAY_SIZE(tail_call_tests); i++)
|
||||
if (progs->ptrs[i])
|
||||
bpf_prog_free(progs->ptrs[i]);
|
||||
kfree(progs);
|
||||
}
|
||||
|
||||
static __init int prepare_tail_call_tests(struct bpf_array **pprogs)
|
||||
{
|
||||
int ntests = ARRAY_SIZE(tail_call_tests);
|
||||
struct bpf_array *progs;
|
||||
int which, err;
|
||||
|
||||
/* Allocate the table of programs to be used for tall calls */
|
||||
progs = kzalloc(sizeof(*progs) + (ntests + 1) * sizeof(progs->ptrs[0]),
|
||||
GFP_KERNEL);
|
||||
if (!progs)
|
||||
goto out_nomem;
|
||||
|
||||
/* Create all eBPF programs and populate the table */
|
||||
for (which = 0; which < ntests; which++) {
|
||||
struct tail_call_test *test = &tail_call_tests[which];
|
||||
struct bpf_prog *fp;
|
||||
int len, i;
|
||||
|
||||
/* Compute the number of program instructions */
|
||||
for (len = 0; len < MAX_INSNS; len++) {
|
||||
struct bpf_insn *insn = &test->insns[len];
|
||||
|
||||
if (len < MAX_INSNS - 1 &&
|
||||
insn->code == (BPF_LD | BPF_DW | BPF_IMM))
|
||||
len++;
|
||||
if (insn->code == 0)
|
||||
break;
|
||||
}
|
||||
|
||||
/* Allocate and initialize the program */
|
||||
fp = bpf_prog_alloc(bpf_prog_size(len), 0);
|
||||
if (!fp)
|
||||
goto out_nomem;
|
||||
|
||||
fp->len = len;
|
||||
fp->type = BPF_PROG_TYPE_SOCKET_FILTER;
|
||||
fp->aux->stack_depth = test->stack_depth;
|
||||
memcpy(fp->insnsi, test->insns, len * sizeof(struct bpf_insn));
|
||||
|
||||
/* Relocate runtime tail call offsets and addresses */
|
||||
for (i = 0; i < len; i++) {
|
||||
struct bpf_insn *insn = &fp->insnsi[i];
|
||||
|
||||
if (insn->imm != TAIL_CALL_MARKER)
|
||||
continue;
|
||||
|
||||
switch (insn->code) {
|
||||
case BPF_LD | BPF_DW | BPF_IMM:
|
||||
insn[0].imm = (u32)(long)progs;
|
||||
insn[1].imm = ((u64)(long)progs) >> 32;
|
||||
break;
|
||||
|
||||
case BPF_ALU | BPF_MOV | BPF_K:
|
||||
if (insn->off == TAIL_CALL_NULL)
|
||||
insn->imm = ntests;
|
||||
else if (insn->off == TAIL_CALL_INVALID)
|
||||
insn->imm = ntests + 1;
|
||||
else
|
||||
insn->imm = which + insn->off;
|
||||
insn->off = 0;
|
||||
}
|
||||
}
|
||||
|
||||
fp = bpf_prog_select_runtime(fp, &err);
|
||||
if (err)
|
||||
goto out_err;
|
||||
|
||||
progs->ptrs[which] = fp;
|
||||
}
|
||||
|
||||
/* The last entry contains a NULL program pointer */
|
||||
progs->map.max_entries = ntests + 1;
|
||||
*pprogs = progs;
|
||||
return 0;
|
||||
|
||||
out_nomem:
|
||||
err = -ENOMEM;
|
||||
|
||||
out_err:
|
||||
if (progs)
|
||||
destroy_tail_call_tests(progs);
|
||||
return err;
|
||||
}
|
||||
|
||||
static __init int test_tail_calls(struct bpf_array *progs)
|
||||
{
|
||||
int i, err_cnt = 0, pass_cnt = 0;
|
||||
int jit_cnt = 0, run_cnt = 0;
|
||||
|
||||
for (i = 0; i < ARRAY_SIZE(tail_call_tests); i++) {
|
||||
struct tail_call_test *test = &tail_call_tests[i];
|
||||
struct bpf_prog *fp = progs->ptrs[i];
|
||||
u64 duration;
|
||||
int ret;
|
||||
|
||||
cond_resched();
|
||||
|
||||
pr_info("#%d %s ", i, test->descr);
|
||||
if (!fp) {
|
||||
err_cnt++;
|
||||
continue;
|
||||
}
|
||||
pr_cont("jited:%u ", fp->jited);
|
||||
|
||||
run_cnt++;
|
||||
if (fp->jited)
|
||||
jit_cnt++;
|
||||
|
||||
ret = __run_one(fp, NULL, MAX_TESTRUNS, &duration);
|
||||
if (ret == test->result) {
|
||||
pr_cont("%lld PASS", duration);
|
||||
pass_cnt++;
|
||||
} else {
|
||||
pr_cont("ret %d != %d FAIL", ret, test->result);
|
||||
err_cnt++;
|
||||
}
|
||||
}
|
||||
|
||||
pr_info("%s: Summary: %d PASSED, %d FAILED, [%d/%d JIT'ed]\n",
|
||||
__func__, pass_cnt, err_cnt, jit_cnt, run_cnt);
|
||||
|
||||
return err_cnt ? -EINVAL : 0;
|
||||
}
|
||||
|
||||
static int __init test_bpf_init(void)
|
||||
{
|
||||
struct bpf_array *progs = NULL;
|
||||
int ret;
|
||||
|
||||
ret = prepare_bpf_tests();
|
||||
@ -9002,6 +9242,14 @@ static int __init test_bpf_init(void)
|
||||
if (ret)
|
||||
return ret;
|
||||
|
||||
ret = prepare_tail_call_tests(&progs);
|
||||
if (ret)
|
||||
return ret;
|
||||
ret = test_tail_calls(progs);
|
||||
destroy_tail_call_tests(progs);
|
||||
if (ret)
|
||||
return ret;
|
||||
|
||||
return test_skb_segment();
|
||||
}
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user