netdev - [PATCH 2/5] bpf, docs: Better document the regular load and store instructions

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Message-Id: <20220131183638.3934982-3-hch@lst.de>
Date:   Mon, 31 Jan 2022 19:36:35 +0100
From:   Christoph Hellwig <hch@....de>
To:     Jonathan Corbet <corbet@....net>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>
Cc:     Martin KaFai Lau <kafai@...com>, Song Liu <songliubraving@...com>,
        Yonghong Song <yhs@...com>,
        John Fastabend <john.fastabend@...il.com>,
        KP Singh <kpsingh@...nel.org>, linux-doc@...r.kernel.org,
        netdev@...r.kernel.org, bpf@...r.kernel.org
Subject: [PATCH 2/5] 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@....de>
---
 Documentation/bpf/instruction-set.rst | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/Documentation/bpf/instruction-set.rst b/Documentation/bpf/instruction-set.rst
index 87f6ad62633a5..03da885301722 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
 -----------------
-- 
2.30.2