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authorChristoph Hellwig <hch@lst.de>2022-01-31 21:36:35 +0300
committerAlexei Starovoitov <ast@kernel.org>2022-02-03 20:23:09 +0300
commit63d8c242b9a502f1517b3e8c45d2125649dd5d7b (patch)
tree130dde939bda2cee13ee151812f8050b6c62057f /Documentation/bpf
parentdd33fb571f5cd25c0d0f9d017dba783c85b70b82 (diff)
downloadlinux-63d8c242b9a502f1517b3e8c45d2125649dd5d7b.tar.xz
bpf, docs: Better document the regular load and store instructions
Add a separate section and a little intro blurb for the regular load and store instructions. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20220131183638.3934982-3-hch@lst.de
Diffstat (limited to 'Documentation/bpf')
-rw-r--r--Documentation/bpf/instruction-set.rst17
1 files changed, 12 insertions, 5 deletions
diff --git a/Documentation/bpf/instruction-set.rst b/Documentation/bpf/instruction-set.rst
index 87f6ad62633a..03da88530172 100644
--- a/Documentation/bpf/instruction-set.rst
+++ b/Documentation/bpf/instruction-set.rst
@@ -215,23 +215,30 @@ The mode modifier is one of:
BPF_IMM 0x00 used for 64-bit mov
BPF_ABS 0x20 legacy BPF packet access
BPF_IND 0x40 legacy BPF packet access
- BPF_MEM 0x60 all normal load and store operations
+ BPF_MEM 0x60 regular load and store operations
BPF_ATOMIC 0xc0 atomic operations
============= ===== ====================================
-BPF_MEM | <size> | BPF_STX means::
+
+Regular load and store operations
+---------------------------------
+
+The ``BPF_MEM`` mode modifier is used to encode regular load and store
+instructions that transfer data between a register and memory.
+
+``BPF_MEM | <size> | BPF_STX`` means::
*(size *) (dst_reg + off) = src_reg
-BPF_MEM | <size> | BPF_ST means::
+``BPF_MEM | <size> | BPF_ST`` means::
*(size *) (dst_reg + off) = imm32
-BPF_MEM | <size> | BPF_LDX means::
+``BPF_MEM | <size> | BPF_LDX`` means::
dst_reg = *(size *) (src_reg + off)
-Where size is one of: BPF_B or BPF_H or BPF_W or BPF_DW.
+Where size is one of: ``BPF_B``, ``BPF_H``, ``BPF_W``, or ``BPF_DW``.
Atomic operations
-----------------