diff mbox series

[4/6] bpf, docs: Fully document the ALU opcodes

Message ID 20220103183556.41040-5-hch@lst.de (mailing list archive)
State Accepted
Delegated to: BPF
Headers show
Series [1/6] bpf, docs: Add a setion to explain the basic instruction encoding | expand

Checks

Context Check Description
bpf/vmtest-bpf-next-PR success PR summary
bpf/vmtest-bpf-next success VM_Test
netdev/tree_selection success Not a local patch

Commit Message

Christoph Hellwig Jan. 3, 2022, 6:35 p.m. UTC 
Add pseudo-code to document all the different BPF_ALU / BPF_ALU64
opcodes.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 Documentation/bpf/instruction-set.rst | 30 +++++++++++++--------------
 1 file changed, 15 insertions(+), 15 deletions(-)
diff mbox series

Patch

diff --git a/Documentation/bpf/instruction-set.rst b/Documentation/bpf/instruction-set.rst
index 2987cbb07f7f6..efba4d1931853 100644
--- a/Documentation/bpf/instruction-set.rst
+++ b/Documentation/bpf/instruction-set.rst
@@ -82,24 +82,24 @@  BPF_ALU uses 32-bit wide operands while BPF_ALU64 uses 64-bit wide operands for
 otherwise identical operations.
 The code field encodes the operation as below:
 
-  ========  =====  =========================
+  ========  =====  ==========================
   code      value  description
-  ========  =====  =========================
-  BPF_ADD   0x00
-  BPF_SUB   0x10
-  BPF_MUL   0x20
-  BPF_DIV   0x30
-  BPF_OR    0x40
-  BPF_AND   0x50
-  BPF_LSH   0x60
-  BPF_RSH   0x70
-  BPF_NEG   0x80
-  BPF_MOD   0x90
-  BPF_XOR   0xa0
-  BPF_MOV   0xb0   mov reg to reg
+  ========  =====  ==========================
+  BPF_ADD   0x00   dst += src
+  BPF_SUB   0x10   dst -= src
+  BPF_MUL   0x20   dst \*= src
+  BPF_DIV   0x30   dst /= src
+  BPF_OR    0x40   dst \|= src
+  BPF_AND   0x50   dst &= src
+  BPF_LSH   0x60   dst <<= src
+  BPF_RSH   0x70   dst >>= src
+  BPF_NEG   0x80   dst = ~src
+  BPF_MOD   0x90   dst %= src
+  BPF_XOR   0xa0   dst ^= src
+  BPF_MOV   0xb0   dst = src
   BPF_ARSH  0xc0   sign extending shift right
   BPF_END   0xd0   endianness conversion
-  ========  =====  =========================
+  ========  =====  ==========================
 
 BPF_ADD | BPF_X | BPF_ALU means::