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authorDave Thaler <[email protected]>2022-09-27 18:59:47 +0000
committerAlexei Starovoitov <[email protected]>2022-09-30 13:41:25 -0700
commitee159bdbdbce293e66d7b9249208f367faff5d81 (patch)
tree20fd3190d032d059639ed23a001f18a7ef4d69bb
parent6c7aaffb24efbd5d1ae067b2b629b3ffcc37e18e (diff)
bpf, docs: Add Clang note about BPF_ALU
Add Clang note about BPF_ALU. Signed-off-by: Dave Thaler <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Alexei Starovoitov <[email protected]>
-rw-r--r--Documentation/bpf/clang-notes.rst6
1 files changed, 6 insertions, 0 deletions
diff --git a/Documentation/bpf/clang-notes.rst b/Documentation/bpf/clang-notes.rst
index b15179cb5117..528feddf2db9 100644
--- a/Documentation/bpf/clang-notes.rst
+++ b/Documentation/bpf/clang-notes.rst
@@ -14,6 +14,12 @@ Clang defined "CPU" versions, where a CPU version of 3 corresponds to the curren
Clang can select the eBPF ISA version using ``-mcpu=v3`` for example to select version 3.
+Arithmetic instructions
+=======================
+
+For CPU versions prior to 3, Clang v7.0 and later can enable ``BPF_ALU`` support with
+``-Xclang -target-feature -Xclang +alu32``. In CPU version 3, support is automatically included.
+
Atomic operations
=================