diff options
| author | Martin KaFai Lau <kafai@fb.com> | 2018-07-20 08:14:31 +0300 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2018-07-20 11:25:48 +0300 |
| commit | 36fc3c8c282c01ad1570bd864de52f128d731b75 (patch) | |
| tree | 3ae71065624e4b4321f13045b6ad2f16f612792f | |
| parent | 759b94a00a207ef605f3fd6f6e99570799688145 (diff) | |
| download | linux-36fc3c8c282c01ad1570bd864de52f128d731b75.tar.xz | |
bpf: btf: Clean up BTF_INT_BITS() in uapi btf.h
This patch shrinks the BTF_INT_BITS() mask. The current
btf_int_check_meta() ensures the nr_bits of an integer
cannot exceed 64. Hence, it is mostly an uapi cleanup.
The actual btf usage (i.e. seq_show()) is also modified
to use u8 instead of u16. The verification (e.g. btf_int_check_meta())
path stays as is to deal with invalid BTF situation.
Fixes: 69b693f0aefa ("bpf: btf: Introduce BPF Type Format (BTF)")
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
| -rw-r--r-- | include/uapi/linux/btf.h | 2 | ||||
| -rw-r--r-- | kernel/bpf/btf.c | 16 |
2 files changed, 11 insertions, 7 deletions
diff --git a/include/uapi/linux/btf.h b/include/uapi/linux/btf.h index 0b5ddbe135a4..972265f32871 100644 --- a/include/uapi/linux/btf.h +++ b/include/uapi/linux/btf.h @@ -76,7 +76,7 @@ struct btf_type { */ #define BTF_INT_ENCODING(VAL) (((VAL) & 0x0f000000) >> 24) #define BTF_INT_OFFSET(VAL) (((VAL & 0x00ff0000)) >> 16) -#define BTF_INT_BITS(VAL) ((VAL) & 0x0000ffff) +#define BTF_INT_BITS(VAL) ((VAL) & 0x000000ff) /* Attributes stored in the BTF_INT_ENCODING */ #define BTF_INT_SIGNED (1 << 0) diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index e016ac3afa24..9704934252b3 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -450,7 +450,7 @@ static const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id) */ static bool btf_type_int_is_regular(const struct btf_type *t) { - u16 nr_bits, nr_bytes; + u8 nr_bits, nr_bytes; u32 int_data; int_data = btf_type_int(t); @@ -993,12 +993,16 @@ static void btf_int_bits_seq_show(const struct btf *btf, { u16 left_shift_bits, right_shift_bits; u32 int_data = btf_type_int(t); - u16 nr_bits = BTF_INT_BITS(int_data); - u16 total_bits_offset; - u16 nr_copy_bytes; - u16 nr_copy_bits; + u8 nr_bits = BTF_INT_BITS(int_data); + u8 total_bits_offset; + u8 nr_copy_bytes; + u8 nr_copy_bits; u64 print_num; + /* + * bits_offset is at most 7. + * BTF_INT_OFFSET() cannot exceed 64 bits. + */ total_bits_offset = bits_offset + BTF_INT_OFFSET(int_data); data += BITS_ROUNDDOWN_BYTES(total_bits_offset); bits_offset = BITS_PER_BYTE_MASKED(total_bits_offset); @@ -1028,7 +1032,7 @@ static void btf_int_seq_show(const struct btf *btf, const struct btf_type *t, u32 int_data = btf_type_int(t); u8 encoding = BTF_INT_ENCODING(int_data); bool sign = encoding & BTF_INT_SIGNED; - u32 nr_bits = BTF_INT_BITS(int_data); + u8 nr_bits = BTF_INT_BITS(int_data); if (bits_offset || BTF_INT_OFFSET(int_data) || BITS_PER_BYTE_MASKED(nr_bits)) { |