On powerpc, immediate load instructions are sign extended. In case of unsigned types, arguments should be explicitly zero-extended by the caller. For kfunc call, this needs to be handled in the JIT code. While kfunc_call_test4 test case already checks for sign-extension of signed argument types in kfunc calls, zero-extension for unsigned argument types is being checked with this test case.
Signed-off-by: Hari Bathini <[email protected]> --- - powerpc BPF JIT was not handling ABI sign-extension & zero-extension appropriately for kfunc calls. Fixed with: https://lore.kernel.org/all/[email protected]/ .../selftests/bpf/prog_tests/kfunc_call.c | 1 + .../selftests/bpf/progs/kfunc_call_test.c | 34 +++++++++++++++++++ .../selftests/bpf/test_kmods/bpf_testmod.c | 28 +++++++++++++++ .../bpf/test_kmods/bpf_testmod_kfunc.h | 1 + 4 files changed, 64 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/kfunc_call.c b/tools/testing/selftests/bpf/prog_tests/kfunc_call.c index f79c8e53cb3e..fb06f2485197 100644 --- a/tools/testing/selftests/bpf/prog_tests/kfunc_call.c +++ b/tools/testing/selftests/bpf/prog_tests/kfunc_call.c @@ -74,6 +74,7 @@ static struct kfunc_test_params kfunc_tests[] = { TC_TEST(kfunc_call_test1, 12), TC_TEST(kfunc_call_test2, 3), TC_TEST(kfunc_call_test4, -1234), + TC_TEST(kfunc_call_test5, 0), 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 8b86113a0126..a32c3a60fa4f 100644 --- a/tools/testing/selftests/bpf/progs/kfunc_call_test.c +++ b/tools/testing/selftests/bpf/progs/kfunc_call_test.c @@ -4,6 +4,40 @@ #include <bpf/bpf_helpers.h> #include "../test_kmods/bpf_testmod_kfunc.h" +SEC("tc") +int kfunc_call_test5(struct __sk_buff *skb) +{ + struct bpf_sock *sk = skb->sk; + int ret; + u32 val32; + u16 val16; + u8 val8; + + if (!sk) + return -1; + + sk = bpf_sk_fullsock(sk); + if (!sk) + return -1; + + ret = bpf_kfunc_call_test5(0xFF, 0xFFFF, 0xFFFFFFFF); + if (ret) + return ret; + + val32 = bpf_get_prandom_u32(); + val16 = val32 & 0xFFFF; + val8 = val32 & 0xFF; + ret = bpf_kfunc_call_test5(val8, val16, val32); + if (ret) + return ret; + + ret = bpf_kfunc_call_test5(val8 * 0xFF, val16 * 0xFFFF, val32 * 0xFFFFFFFF); + if (ret) + return ret; + + return 0; +} + SEC("tc") int kfunc_call_test4(struct __sk_buff *skb) { diff --git a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c index e62c6b78657f..de4897ddcff1 100644 --- a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c +++ b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c @@ -766,6 +766,33 @@ __bpf_kfunc long noinline bpf_kfunc_call_test4(signed char a, short b, int c, lo return (long)a + (long)b + (long)c + d; } +__bpf_kfunc int bpf_kfunc_call_test5(u8 a, u16 b, u32 c) +{ + /* Make val as volatile to avoid compiler optimizations on the below checks */ + volatile long val = a; + + /* Check zero-extension */ + if (val != (unsigned long)a) + return 1; + /* Check no sign-extension */ + if (val < 0) + return 2; + + val = b; + if (val != (unsigned long)b) + return 3; + if (val < 0) + return 4; + + val = c; + if (val != (unsigned long)c) + return 5; + if (val < 0) + return 6; + + return 0; +} + static struct prog_test_ref_kfunc prog_test_struct = { .a = 42, .b = 108, @@ -1228,6 +1255,7 @@ 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_test5) BTF_ID_FLAGS(func, bpf_kfunc_call_test_mem_len_pass1) BTF_ID_FLAGS(func, bpf_kfunc_call_test_mem_len_fail1) BTF_ID_FLAGS(func, bpf_kfunc_call_test_mem_len_fail2) diff --git a/tools/testing/selftests/bpf/test_kmods/bpf_testmod_kfunc.h b/tools/testing/selftests/bpf/test_kmods/bpf_testmod_kfunc.h index b393bf771131..aa0b8d41e71b 100644 --- a/tools/testing/selftests/bpf/test_kmods/bpf_testmod_kfunc.h +++ b/tools/testing/selftests/bpf/test_kmods/bpf_testmod_kfunc.h @@ -110,6 +110,7 @@ __u64 bpf_kfunc_call_test1(struct sock *sk, __u32 a, __u64 b, int bpf_kfunc_call_test2(struct sock *sk, __u32 a, __u32 b) __ksym; struct sock *bpf_kfunc_call_test3(struct sock *sk) __ksym; long bpf_kfunc_call_test4(signed char a, short b, int c, long d) __ksym; +int bpf_kfunc_call_test5(__u8 a, __u16 b, __u32 c) __ksym; void bpf_kfunc_call_test_pass_ctx(struct __sk_buff *skb) __ksym; void bpf_kfunc_call_test_pass1(struct prog_test_pass1 *p) __ksym; -- 2.53.0
