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.
Signed-off-by: Daniel Xu dxu@dxuuu.xyz --- .../selftests/bpf/prog_tests/verifier.c | 2 + .../bpf/progs/verifier_bitfield_write.c | 100 ++++++++++++++++++ 2 files changed, 102 insertions(+) create mode 100644 tools/testing/selftests/bpf/progs/verifier_bitfield_write.c
diff --git a/tools/testing/selftests/bpf/prog_tests/verifier.c b/tools/testing/selftests/bpf/prog_tests/verifier.c index 5cfa7a6316b6..67b4948865a3 100644 --- a/tools/testing/selftests/bpf/prog_tests/verifier.c +++ b/tools/testing/selftests/bpf/prog_tests/verifier.c @@ -6,6 +6,7 @@ #include "verifier_and.skel.h" #include "verifier_array_access.skel.h" #include "verifier_basic_stack.skel.h" +#include "verifier_bitfield_write.skel.h" #include "verifier_bounds.skel.h" #include "verifier_bounds_deduction.skel.h" #include "verifier_bounds_deduction_non_const.skel.h" @@ -115,6 +116,7 @@ static void run_tests_aux(const char *skel_name,
void test_verifier_and(void) { RUN(verifier_and); } void test_verifier_basic_stack(void) { RUN(verifier_basic_stack); } +void test_verifier_bitfield_write(void) { RUN(verifier_bitfield_write); } void test_verifier_bounds(void) { RUN(verifier_bounds); } void test_verifier_bounds_deduction(void) { RUN(verifier_bounds_deduction); } void test_verifier_bounds_deduction_non_const(void) { RUN(verifier_bounds_deduction_non_const); } 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..8fe355a19ba6 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/verifier_bitfield_write.c @@ -0,0 +1,100 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <linux/bpf.h> +#include <stdint.h> + +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_core_read.h> + +#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 __failure_unpriv +__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 __failure_unpriv +__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 __failure_unpriv +__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 __failure_unpriv +__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";