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selftests/bpf: Add a sign-extension test for kfuncs

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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 <iii@linux.ibm.com>
Link: https://lore.kernel.org/r/20230128000650.1516334-15-iii@linux.ibm.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Ilya Leoshkevich 2023-01-28 01:06:33 +01:00 committed by Alexei Starovoitov
parent 80a611904e
commit be6b5c10ec
3 changed files with 28 additions and 0 deletions
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9
net/bpf/test_run.c
View File

@ -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)

1
tools/testing/selftests/bpf/prog_tests/kfunc_call.c
View File

@ -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),

18
tools/testing/selftests/bpf/progs/kfunc_call_test.c
View File

@ -3,6 +3,7 @@
#include <vmlinux.h>
#include <bpf/bpf_helpers.h>
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;
@ -17,6 +18,23 @@ extern void bpf_kfunc_call_test_mem_len_fail2(__u64 *mem, int len) __ksym;
extern int *bpf_kfunc_call_test_get_rdwr_mem(struct prog_test_ref_kfunc *p, const int rdwr_buf_size) __ksym;
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)
{