From f04f2ce6018f3cb33ac96270b9153c2920ead190 Mon Sep 17 00:00:00 2001 From: Daniel Xu Date: Mon, 11 Dec 2023 13:20:09 -0700 Subject: bpf: selftests: Add verifier tests for CO-RE bitfield writes Add some tests that exercise BPF_CORE_WRITE_BITFIELD() macro. Since some non-trivial bit fiddling is going on, make sure various edge cases (such as adjacent bitfields and bitfields at the edge of structs) are exercised. Acked-by: Andrii Nakryiko Signed-off-by: Daniel Xu Link: https://lore.kernel.org/r/72698a1080fa565f541d5654705255984ea2a029.1702325874.git.dxu@dxuuu.xyz Signed-off-by: Martin KaFai Lau --- .../selftests/bpf/progs/verifier_bitfield_write.c | 100 +++++++++++++++++++++ 1 file changed, 100 insertions(+) create mode 100644 tools/testing/selftests/bpf/progs/verifier_bitfield_write.c (limited to 'tools/testing/selftests/bpf/progs/verifier_bitfield_write.c') diff --git a/tools/testing/selftests/bpf/progs/verifier_bitfield_write.c b/tools/testing/selftests/bpf/progs/verifier_bitfield_write.c new file mode 100644 index 000000000000..623f130a3198 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/verifier_bitfield_write.c @@ -0,0 +1,100 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include + +#include +#include + +#include "bpf_misc.h" + +struct core_reloc_bitfields { + /* unsigned bitfields */ + uint8_t ub1: 1; + uint8_t ub2: 2; + uint32_t ub7: 7; + /* signed bitfields */ + int8_t sb4: 4; + int32_t sb20: 20; + /* non-bitfields */ + uint32_t u32; + int32_t s32; +} __attribute__((preserve_access_index)); + +SEC("tc") +__description("single CO-RE bitfield roundtrip") +__btf_path("btf__core_reloc_bitfields.bpf.o") +__success +__retval(3) +int single_field_roundtrip(struct __sk_buff *ctx) +{ + struct core_reloc_bitfields bitfields; + + __builtin_memset(&bitfields, 0, sizeof(bitfields)); + BPF_CORE_WRITE_BITFIELD(&bitfields, ub2, 3); + return BPF_CORE_READ_BITFIELD(&bitfields, ub2); +} + +SEC("tc") +__description("multiple CO-RE bitfield roundtrip") +__btf_path("btf__core_reloc_bitfields.bpf.o") +__success +__retval(0x3FD) +int multiple_field_roundtrip(struct __sk_buff *ctx) +{ + struct core_reloc_bitfields bitfields; + uint8_t ub2; + int8_t sb4; + + __builtin_memset(&bitfields, 0, sizeof(bitfields)); + BPF_CORE_WRITE_BITFIELD(&bitfields, ub2, 1); + BPF_CORE_WRITE_BITFIELD(&bitfields, sb4, -1); + + ub2 = BPF_CORE_READ_BITFIELD(&bitfields, ub2); + sb4 = BPF_CORE_READ_BITFIELD(&bitfields, sb4); + + return (((uint8_t)sb4) << 2) | ub2; +} + +SEC("tc") +__description("adjacent CO-RE bitfield roundtrip") +__btf_path("btf__core_reloc_bitfields.bpf.o") +__success +__retval(7) +int adjacent_field_roundtrip(struct __sk_buff *ctx) +{ + struct core_reloc_bitfields bitfields; + uint8_t ub1, ub2; + + __builtin_memset(&bitfields, 0, sizeof(bitfields)); + BPF_CORE_WRITE_BITFIELD(&bitfields, ub1, 1); + BPF_CORE_WRITE_BITFIELD(&bitfields, ub2, 3); + + ub1 = BPF_CORE_READ_BITFIELD(&bitfields, ub1); + ub2 = BPF_CORE_READ_BITFIELD(&bitfields, ub2); + + return (ub2 << 1) | ub1; +} + +SEC("tc") +__description("multibyte CO-RE bitfield roundtrip") +__btf_path("btf__core_reloc_bitfields.bpf.o") +__success +__retval(0x21) +int multibyte_field_roundtrip(struct __sk_buff *ctx) +{ + struct core_reloc_bitfields bitfields; + uint32_t ub7; + uint8_t ub1; + + __builtin_memset(&bitfields, 0, sizeof(bitfields)); + BPF_CORE_WRITE_BITFIELD(&bitfields, ub1, 1); + BPF_CORE_WRITE_BITFIELD(&bitfields, ub7, 16); + + ub1 = BPF_CORE_READ_BITFIELD(&bitfields, ub1); + ub7 = BPF_CORE_READ_BITFIELD(&bitfields, ub7); + + return (ub7 << 1) | ub1; +} + +char _license[] SEC("license") = "GPL"; -- cgit