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Diffstat (limited to 'Documentation/bpf')
| -rw-r--r-- | Documentation/bpf/btf.rst | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/Documentation/bpf/btf.rst b/Documentation/bpf/btf.rst index 8820360d00da..4d565d202ce3 100644 --- a/Documentation/bpf/btf.rst +++ b/Documentation/bpf/btf.rst @@ -131,7 +131,7 @@ The following sections detail encoding of each kind. ``btf_type`` is followed by a ``u32`` with the following bits arrangement:: #define BTF_INT_ENCODING(VAL) (((VAL) & 0x0f000000) >> 24) - #define BTF_INT_OFFSET(VAL) (((VAL & 0x00ff0000)) >> 16) + #define BTF_INT_OFFSET(VAL) (((VAL) & 0x00ff0000) >> 16) #define BTF_INT_BITS(VAL) ((VAL) & 0x000000ff) The ``BTF_INT_ENCODING`` has the following attributes:: @@ -151,6 +151,7 @@ for the type. The maximum value of ``BTF_INT_BITS()`` is 128. The ``BTF_INT_OFFSET()`` specifies the starting bit offset to calculate values for this int. For example, a bitfield struct member has: + * btf member bit offset 100 from the start of the structure, * btf member pointing to an int type, * the int type has ``BTF_INT_OFFSET() = 2`` and ``BTF_INT_BITS() = 4`` @@ -160,6 +161,7 @@ from bits ``100 + 2 = 102``. Alternatively, the bitfield struct member can be the following to access the same bits as the above: + * btf member bit offset 102, * btf member pointing to an int type, * the int type has ``BTF_INT_OFFSET() = 0`` and ``BTF_INT_BITS() = 4`` |