Commit 918ba263 authored by Emil Tsalapatis's avatar Emil Tsalapatis Committed by Alexei Starovoitov
Browse files

selftests: bpf: add bpf_cpumask_populate selftests 



Add selftests for the bpf_cpumask_populate helper that sets a
bpf_cpumask to a bit pattern provided by a BPF program.

Signed-off-by: default avatarEmil Tsalapatis (Meta) <emil@etsalapatis.com>
Acked-by: default avatarHou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20250309230427.26603-3-emil@etsalapatis.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 950ad93d

tools/testing/selftests/bpf/prog_tests/cpumask.c

+3 −0
Original line number Diff line number Diff line
@@ -25,6 +25,9 @@ static const char * const cpumask_success_testcases[] = { 
	"test_global_mask_nested_deep_rcu",

	"test_global_mask_nested_deep_array_rcu",

	"test_cpumask_weight",

	"test_populate_reject_small_mask",

	"test_populate_reject_unaligned",

	"test_populate",

};



static void verify_success(const char *prog_name)

tools/testing/selftests/bpf/progs/cpumask_common.h

+1 −0
Original line number Diff line number Diff line
@@ -61,6 +61,7 @@ u32 bpf_cpumask_any_distribute(const struct cpumask *src) __ksym __weak; 
u32 bpf_cpumask_any_and_distribute(const struct cpumask *src1,

				   const struct cpumask *src2) __ksym __weak;

u32 bpf_cpumask_weight(const struct cpumask *cpumask) __ksym __weak;

int bpf_cpumask_populate(struct cpumask *cpumask, void *src, size_t src__sz) __ksym __weak;



void bpf_rcu_read_lock(void) __ksym __weak;

void bpf_rcu_read_unlock(void) __ksym __weak;

tools/testing/selftests/bpf/progs/cpumask_failure.c

+38 −0
Original line number Diff line number Diff line
@@ -222,3 +222,41 @@ int BPF_PROG(test_invalid_nested_array, struct task_struct *task, u64 clone_flag 


	return 0;

}



SEC("tp_btf/task_newtask")

__failure __msg("type=scalar expected=fp")

int BPF_PROG(test_populate_invalid_destination, struct task_struct *task, u64 clone_flags)

{

	struct bpf_cpumask *invalid = (struct bpf_cpumask *)0x123456;

	u64 bits;

	int ret;



	ret = bpf_cpumask_populate((struct cpumask *)invalid, &bits, sizeof(bits));

	if (!ret)

		err = 2;



	return 0;

}



SEC("tp_btf/task_newtask")

__failure __msg("leads to invalid memory access")

int BPF_PROG(test_populate_invalid_source, struct task_struct *task, u64 clone_flags)

{

	void *garbage = (void *)0x123456;

	struct bpf_cpumask *local;

	int ret;



	local = create_cpumask();

	if (!local) {

		err = 1;

		return 0;

	}



	ret = bpf_cpumask_populate((struct cpumask *)local, garbage, 8);

	if (!ret)

		err = 2;



	bpf_cpumask_release(local);



	return 0;

}

tools/testing/selftests/bpf/progs/cpumask_success.c

+119 −0
Original line number Diff line number Diff line
@@ -770,3 +770,122 @@ int BPF_PROG(test_refcount_null_tracking, struct task_struct *task, u64 clone_fl 
		bpf_cpumask_release(mask2);

	return 0;

}



SEC("tp_btf/task_newtask")

int BPF_PROG(test_populate_reject_small_mask, struct task_struct *task, u64 clone_flags)

{

	struct bpf_cpumask *local;

	u8 toofewbits;

	int ret;



	if (!is_test_task())

		return 0;



	local = create_cpumask();

	if (!local)

		return 0;



	/* The kfunc should prevent this operation */

	ret = bpf_cpumask_populate((struct cpumask *)local, &toofewbits, sizeof(toofewbits));

	if (ret != -EACCES)

		err = 2;



	bpf_cpumask_release(local);



	return 0;

}



/* Mask is guaranteed to be large enough for bpf_cpumask_t. */

#define CPUMASK_TEST_MASKLEN (sizeof(cpumask_t))



/* Add an extra word for the test_populate_reject_unaligned test. */

u64 bits[CPUMASK_TEST_MASKLEN / 8 + 1];

extern bool CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS __kconfig __weak;



SEC("tp_btf/task_newtask")

int BPF_PROG(test_populate_reject_unaligned, struct task_struct *task, u64 clone_flags)

{

	struct bpf_cpumask *mask;

	char *src;

	int ret;



	if (!is_test_task())

		return 0;



	/* Skip if unaligned accesses are fine for this arch.  */

	if (CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)

		return 0;



	mask = bpf_cpumask_create();

	if (!mask) {

		err = 1;

		return 0;

	}



	/* Misalign the source array by a byte. */

	src = &((char *)bits)[1];



	ret = bpf_cpumask_populate((struct cpumask *)mask, src, CPUMASK_TEST_MASKLEN);

	if (ret != -EINVAL)

		err = 2;



	bpf_cpumask_release(mask);



	return 0;

}





SEC("tp_btf/task_newtask")

int BPF_PROG(test_populate, struct task_struct *task, u64 clone_flags)

{

	struct bpf_cpumask *mask;

	bool bit;

	int ret;

	int i;



	if (!is_test_task())

		return 0;



	/* Set only odd bits. */

	__builtin_memset(bits, 0xaa, CPUMASK_TEST_MASKLEN);



	mask = bpf_cpumask_create();

	if (!mask) {

		err = 1;

		return 0;

	}



	/* Pass the entire bits array, the kfunc will only copy the valid bits. */

	ret = bpf_cpumask_populate((struct cpumask *)mask, bits, CPUMASK_TEST_MASKLEN);

	if (ret) {

		err = 2;

		goto out;

	}



	/*

	 * Test is there to appease the verifier. We cannot directly

	 * access NR_CPUS, the upper bound for nr_cpus, so we infer

	 * it from the size of cpumask_t.

	 */

	if (nr_cpus < 0 || nr_cpus >= CPUMASK_TEST_MASKLEN * 8) {

		err = 3;

		goto out;

	}



	bpf_for(i, 0, nr_cpus) {

		/* Odd-numbered bits should be set, even ones unset. */

		bit = bpf_cpumask_test_cpu(i, (const struct cpumask *)mask);

		if (bit == (i % 2 != 0))

			continue;



		err = 4;

		break;

	}



out:

	bpf_cpumask_release(mask);



	return 0;

}



#undef CPUMASK_TEST_MASKLEN