Commit 3b2ec214 authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by Andrii Nakryiko
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selftests/bpf: Add light skeleton test for kfunc detection. 



Add light skeleton test for kfunc detection and denylist it for s390.

Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230321203854.3035-5-alexei.starovoitov@gmail.com
parent 708cdc57

tools/testing/selftests/bpf/DENYLIST.s390x

+1 −0
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ get_stack_raw_tp # user_stack corrupted user stack 
iters/testmod_seq*                       # s390x doesn't support kfuncs in modules yet

kprobe_multi_bench_attach                # bpf_program__attach_kprobe_multi_opts unexpected error: -95

kprobe_multi_test                        # relies on fentry

ksyms_btf/weak_ksyms*                    # test_ksyms_weak__open_and_load unexpected error: -22                        (kfunc)

ksyms_module                             # test_ksyms_module__open_and_load unexpected error: -9                       (?)

ksyms_module_libbpf                      # JIT does not support calling kernel function                                (kfunc)

ksyms_module_lskel                       # test_ksyms_module_lskel__open_and_load unexpected error: -9                 (?)

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

+15 −0
Original line number Diff line number Diff line
@@ -20,6 +20,8 @@ __u64 out__non_existent_typed = -1; 
/* test existing weak symbols can be resolved. */

extern const struct rq runqueues __ksym __weak; /* typed */

extern const void bpf_prog_active __ksym __weak; /* typeless */

struct task_struct *bpf_task_acquire(struct task_struct *p) __ksym __weak;

void bpf_testmod_test_mod_kfunc(int i) __ksym __weak;





/* non-existent weak symbols. */
@@ -29,6 +31,7 @@ extern const void bpf_link_fops1 __ksym __weak; 


/* typed symbols, default to zero. */

extern const int bpf_link_fops2 __ksym __weak;

void invalid_kfunc(void) __ksym __weak;



SEC("raw_tp/sys_enter")

int pass_handler(const void *ctx)
@@ -50,6 +53,18 @@ int pass_handler(const void *ctx) 
	if (&bpf_link_fops2) /* can't happen */

		out__non_existent_typed = (__u64)bpf_per_cpu_ptr(&bpf_link_fops2, 0);



	if (!bpf_ksym_exists(bpf_task_acquire))

		/* dead code won't be seen by the verifier */

		bpf_task_acquire(0);



	if (!bpf_ksym_exists(bpf_testmod_test_mod_kfunc))

		/* dead code won't be seen by the verifier */

		bpf_testmod_test_mod_kfunc(0);



	if (bpf_ksym_exists(invalid_kfunc))

		/* dead code won't be seen by the verifier */

		invalid_kfunc();



	return 0;

}