Add selftests that exercise a 16-byte return value passed in the R0:R2 register pair, written in C so that they depend on the compiler lowering the register-pair return. The R0:R2 convention is only emitted by LLVM 23 and newer, and a by-value aggregate return does not compile at all before that, so the programs sit behind a __clang_major__ guard. An older compiler builds the dummy test in the #else branch instead, which keeps the object non-empty and says in its description why nothing was exercised. The kfunc tests are tagged __arch_x86_64/__arch_arm64 and skip elsewhere. Those are the architectures whose JIT advertises bpf_jit_supports_kfunc_ret_reg_pair(), which bpf_add_kfunc_call() requires before it accepts a kfunc returning more than 8 bytes, and they are also the only ones building the kfuncs. Acked-by: Eduard Zingerman Signed-off-by: Yonghong Song --- .../selftests/bpf/prog_tests/verifier.c | 2 + .../bpf/progs/verifier_aggregate_ret.c | 178 ++++++++++++++++++ .../selftests/bpf/test_kmods/bpf_testmod.c | 18 ++ .../bpf/test_kmods/bpf_testmod_kfunc.h | 9 + 4 files changed, 207 insertions(+) create mode 100644 tools/testing/selftests/bpf/progs/verifier_aggregate_ret.c diff --git a/tools/testing/selftests/bpf/prog_tests/verifier.c b/tools/testing/selftests/bpf/prog_tests/verifier.c index 64ac49ad67e6..f7f94ccebce2 100644 --- a/tools/testing/selftests/bpf/prog_tests/verifier.c +++ b/tools/testing/selftests/bpf/prog_tests/verifier.c @@ -5,6 +5,7 @@ #include "arena_kfunc.skel.h" #include "arena_kfunc_jit.skel.h" #include "cap_helpers.h" +#include "verifier_aggregate_ret.skel.h" #include "verifier_align.skel.h" #include "verifier_and.skel.h" #include "verifier_arena.skel.h" @@ -170,6 +171,7 @@ void test_arena_kfunc(void) { RUN_TESTS(arena_kfunc); } void test_arena_kfunc_jit(void) { RUN_TESTS(arena_kfunc_jit); } +void test_verifier_aggregate_ret(void) { RUN_TESTS(verifier_aggregate_ret); } void test_verifier_align(void) { RUN(verifier_align); } void test_verifier_and(void) { RUN(verifier_and); } void test_verifier_arena(void) { RUN(verifier_arena); } diff --git a/tools/testing/selftests/bpf/progs/verifier_aggregate_ret.c b/tools/testing/selftests/bpf/progs/verifier_aggregate_ret.c new file mode 100644 index 000000000000..7851bade2b40 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/verifier_aggregate_ret.c @@ -0,0 +1,178 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2026 Meta Platforms, Inc. and affiliates. */ +#include +#include +#include "../test_kmods/bpf_testmod_kfunc.h" +#include "bpf_misc.h" + +#if defined(__clang_major__) && __clang_major__ >= 23 + +#define MIX_A 0xdeadbeefcafef00dULL +#define MIX_B 0x0123456789abcdefULL + +typedef unsigned __int128 u128; + +struct pair { + __u64 lo; /* R0 */ + __u64 hi; /* R2 */ +}; + +union upair { + __u64 halves[2]; + struct { + __u64 lo; /* R0 */ + __u64 hi; /* R2 */ + } parts; +}; + +static __noinline u128 make_i128(__u64 a, __u64 b) +{ + return ((u128)(a + b) << 64) | (a - b); +} + +SEC("tc") +__load_if_JITed() +__success __retval(0) +int aggregate_ret_int128_c_test(struct __sk_buff *skb) +{ + __u64 a = skb->len ^ MIX_A; + __u64 b = skb->len ^ MIX_B; + u128 v; + + v = make_i128(a, b); + if ((__u64)(v >> 64) != a + b) + return 1; + if ((__u64)v != a - b) + return 2; + + return 0; +} + +static __noinline struct pair make_pair(__u64 a, __u64 b) +{ + struct pair p = { .lo = a + b, .hi = a - b }; + + return p; +} + +SEC("tc") +__load_if_JITed() +__success __retval(0) +int aggregate_ret_struct_c_test(struct __sk_buff *skb) +{ + __u64 a = skb->len ^ MIX_A; + __u64 b = skb->len ^ MIX_B; + struct pair p; + + p = make_pair(a, b); + if (p.lo != a + b) + return 1; + if (p.hi != a - b) + return 2; + + return 0; +} + +__noinline struct pair make_pair_global(__u64 a, __u64 b) +{ + struct pair p = { .lo = a + b, .hi = a - b }; + + return p; +} + +SEC("tc") +__load_if_JITed() +__success __retval(0) +int aggregate_ret_global_struct_c_test(struct __sk_buff *skb) +{ + __u64 a = skb->len ^ MIX_A; + __u64 b = skb->len ^ MIX_B; + struct pair p; + + p = make_pair_global(a, b); + if (p.lo != a + b) + return 1; + if (p.hi != a - b) + return 2; + + return 0; +} + +static __noinline union upair make_upair(__u64 a, __u64 b) +{ + union upair p; + + p.halves[0] = a + b; + p.halves[1] = a - b; + return p; +} + +SEC("tc") +__load_if_JITed() +__success __retval(0) +int aggregate_ret_union_c_test(struct __sk_buff *skb) +{ + __u64 a = skb->len ^ MIX_A; + __u64 b = skb->len ^ MIX_B; + union upair p; + + p = make_upair(a, b); + if (p.parts.lo != a + b) + return 1; + if (p.parts.hi != a - b) + return 2; + + return 0; +} + +SEC("tc") +__arch_x86_64 __arch_arm64 +__load_if_JITed() +__success __retval(0) +int aggregate_ret_kfunc_int128_c_test(struct __sk_buff *skb) +{ + __u64 a = skb->len ^ MIX_A; + __u64 b = skb->len ^ MIX_B; + u128 v; + + v = bpf_kfunc_call_test_i128(a, b); + if ((__u64)(v >> 64) != a + b) + return 1; + if ((__u64)v != a - b) + return 2; + + return 0; +} + +SEC("tc") +__arch_x86_64 __arch_arm64 +__load_if_JITed() +__success __retval(0) +int aggregate_ret_kfunc_struct_c_test(struct __sk_buff *skb) +{ + __u64 a = skb->len ^ MIX_A; + __u64 b = skb->len ^ MIX_B; + struct prog_test_ret_pair p; + + p = bpf_kfunc_call_test_ret_pair(a, b); + if (p.lo != a + b) + return 1; + if (p.hi != a - b) + return 2; + + return 0; +} + +#else + +SEC("socket") +__description("verifier_aggregate_ret: needs LLVM 23, dummy test") +__success +int dummy_test(void) +{ + return 0; +} + +#endif + +char _license[] SEC("license") = "GPL"; diff --git a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c index 9366a3c578f1..c4bc8e11c6e1 100644 --- a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c +++ b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c @@ -954,6 +954,20 @@ __bpf_kfunc int bpf_kfunc_call_test5(u8 a, u16 b, u32 c) return 0; } +#if defined(__x86_64__) || defined(__aarch64__) +__bpf_kfunc __int128 bpf_kfunc_call_test_i128(u64 a, u64 b) +{ + return (__int128)(((unsigned __int128)(a + b) << 64) | (a - b)); +} + +__bpf_kfunc struct prog_test_ret_pair bpf_kfunc_call_test_ret_pair(u64 a, u64 b) +{ + struct prog_test_ret_pair r = { .lo = a + b, .hi = a - b }; + + return r; +} +#endif /* __x86_64__ || __aarch64__ */ + __bpf_kfunc u64 bpf_kfunc_call_stack_arg(u64 a, u64 b, u64 c, u64 d, u64 e, u64 f, u64 g, u64 h, u64 i, u64 j) @@ -1487,6 +1501,10 @@ 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) +#if defined(__x86_64__) || defined(__aarch64__) +BTF_ID_FLAGS(func, bpf_kfunc_call_test_i128) +BTF_ID_FLAGS(func, bpf_kfunc_call_test_ret_pair) +#endif BTF_ID_FLAGS(func, bpf_kfunc_call_stack_arg) BTF_ID_FLAGS(func, bpf_kfunc_call_stack_arg_ptr) BTF_ID_FLAGS(func, bpf_kfunc_call_stack_arg_mix) 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 7d81070eefe7..426000f9a14f 100644 --- a/tools/testing/selftests/bpf/test_kmods/bpf_testmod_kfunc.h +++ b/tools/testing/selftests/bpf/test_kmods/bpf_testmod_kfunc.h @@ -55,6 +55,11 @@ struct prog_test_big_arg { __u64 b; }; +struct prog_test_ret_pair { /* 16 bytes: R0:R2 */ + __u64 lo; + __u64 hi; +}; + struct prog_test_fail1 { void *p; int x; @@ -131,6 +136,10 @@ 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; +#ifdef __SIZEOF_INT128__ +__int128 bpf_kfunc_call_test_i128(__u64 a, __u64 b) __ksym; +#endif +struct prog_test_ret_pair bpf_kfunc_call_test_ret_pair(__u64 a, __u64 b) __ksym; __u64 bpf_kfunc_call_stack_arg(__u64 a, __u64 b, __u64 c, __u64 d, __u64 e, __u64 f, __u64 g, __u64 h, __u64 i, __u64 j) __ksym; -- 2.53.0-Meta