From be6b5c10ecc4014446e5c807d6a69c5a7cc1c497 Mon Sep 17 00:00:00 2001 From: Ilya Leoshkevich Date: Sat, 28 Jan 2023 01:06:33 +0100 Subject: [PATCH] selftests/bpf: Add a sign-extension test for kfuncs s390x ABI requires the caller to zero- or sign-extend the arguments. eBPF already deals with zero-extension (by definition of its ABI), but not with sign-extension. Add a test to cover that potentially problematic area. Signed-off-by: Ilya Leoshkevich Link: https://lore.kernel.org/r/20230128000650.1516334-15-iii@linux.ibm.com Signed-off-by: Alexei Starovoitov --- net/bpf/test_run.c | 9 +++++++++ tools/testing/selftests/bpf/prog_tests/kfunc_call.c | 1 + tools/testing/selftests/bpf/progs/kfunc_call_test.c | 18 ++++++++++++++++++ 3 files changed, 28 insertions(+) diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c index 8da0d73..7dbefa4 100644 --- a/net/bpf/test_run.c +++ b/net/bpf/test_run.c @@ -550,6 +550,14 @@ struct sock * noinline bpf_kfunc_call_test3(struct sock *sk) return sk; } +long noinline bpf_kfunc_call_test4(signed char a, short b, int c, long d) +{ + /* Provoke the compiler to assume that the caller has sign-extended a, + * b and c on platforms where this is required (e.g. s390x). + */ + return (long)a + (long)b + (long)c + d; +} + struct prog_test_member1 { int a; }; @@ -746,6 +754,7 @@ BTF_SET8_START(test_sk_check_kfunc_ids) BTF_ID_FLAGS(func, bpf_kfunc_call_test1) BTF_ID_FLAGS(func, bpf_kfunc_call_test2) BTF_ID_FLAGS(func, bpf_kfunc_call_test3) +BTF_ID_FLAGS(func, bpf_kfunc_call_test4) BTF_ID_FLAGS(func, bpf_kfunc_call_test_acquire, KF_ACQUIRE | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_kfunc_call_memb_acquire, KF_ACQUIRE | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_kfunc_call_test_release, KF_RELEASE) diff --git a/tools/testing/selftests/bpf/prog_tests/kfunc_call.c b/tools/testing/selftests/bpf/prog_tests/kfunc_call.c index 5af1ee8..bb4cd82 100644 --- a/tools/testing/selftests/bpf/prog_tests/kfunc_call.c +++ b/tools/testing/selftests/bpf/prog_tests/kfunc_call.c @@ -72,6 +72,7 @@ static struct kfunc_test_params kfunc_tests[] = { /* success cases */ TC_TEST(kfunc_call_test1, 12), TC_TEST(kfunc_call_test2, 3), + TC_TEST(kfunc_call_test4, -1234), TC_TEST(kfunc_call_test_ref_btf_id, 0), TC_TEST(kfunc_call_test_get_mem, 42), SYSCALL_TEST(kfunc_syscall_test, 0), diff --git a/tools/testing/selftests/bpf/progs/kfunc_call_test.c b/tools/testing/selftests/bpf/progs/kfunc_call_test.c index f636e50..d91c58d 100644 --- a/tools/testing/selftests/bpf/progs/kfunc_call_test.c +++ b/tools/testing/selftests/bpf/progs/kfunc_call_test.c @@ -3,6 +3,7 @@ #include #include +extern long bpf_kfunc_call_test4(signed char a, short b, int c, long d) __ksym; extern int bpf_kfunc_call_test2(struct sock *sk, __u32 a, __u32 b) __ksym; extern __u64 bpf_kfunc_call_test1(struct sock *sk, __u32 a, __u64 b, __u32 c, __u64 d) __ksym; @@ -18,6 +19,23 @@ extern int *bpf_kfunc_call_test_get_rdwr_mem(struct prog_test_ref_kfunc *p, cons extern int *bpf_kfunc_call_test_get_rdonly_mem(struct prog_test_ref_kfunc *p, const int rdonly_buf_size) __ksym; SEC("tc") +int kfunc_call_test4(struct __sk_buff *skb) +{ + struct bpf_sock *sk = skb->sk; + long tmp; + + if (!sk) + return -1; + + sk = bpf_sk_fullsock(sk); + if (!sk) + return -1; + + tmp = bpf_kfunc_call_test4(-3, -30, -200, -1000); + return (tmp >> 32) + tmp; +} + +SEC("tc") int kfunc_call_test2(struct __sk_buff *skb) { struct bpf_sock *sk = skb->sk; -- 2.7.4