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authorMartin KaFai Lau <kafai@fb.com>2018-07-19 22:14:31 -0700
committerDaniel Borkmann <daniel@iogearbox.net>2018-07-20 10:25:48 +0200
commit36fc3c8c282c01ad1570bd864de52f128d731b75 (patch)
tree3ae71065624e4b4321f13045b6ad2f16f612792f /kernel
parent759b94a00a207ef605f3fd6f6e99570799688145 (diff)
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>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/bpf/btf.c16
1 files changed, 10 insertions, 6 deletions
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)) {