From 4652072e7b9d643edc9ebb04e3e2c021461b7af0 Mon Sep 17 00:00:00 2001 From: Dave Thaler Date: Fri, 17 May 2024 08:34:45 -0700 Subject: bpf, docs: Move sentence about returning R0 to abi.rst As discussed at LSF/MM/BPF, the sentence about using R0 for returning values from calls is part of the calling convention and belongs in abi.rst. Any further additions or clarifications to this text are left for future patches on abi.rst. The current patch is simply to unblock progression of instruction-set.rst to a standard. In contrast, the restriction of register numbers to the range 0-10 is untouched, left in the instruction-set.rst definition of the src_reg and dst_reg fields. Signed-off-by: Dave Thaler Link: https://lore.kernel.org/r/20240517153445.3914-1-dthaler1968@gmail.com Signed-off-by: Alexei Starovoitov --- Documentation/bpf/standardization/abi.rst | 3 +++ 1 file changed, 3 insertions(+) (limited to 'Documentation/bpf/standardization/abi.rst') diff --git a/Documentation/bpf/standardization/abi.rst b/Documentation/bpf/standardization/abi.rst index 0c2e10eeb89a..41514137cb7b 100644 --- a/Documentation/bpf/standardization/abi.rst +++ b/Documentation/bpf/standardization/abi.rst @@ -23,3 +23,6 @@ The BPF calling convention is defined as: R0 - R5 are scratch registers and BPF programs needs to spill/fill them if necessary across calls. + +The BPF program needs to store the return value into register R0 before doing an +``EXIT``. -- cgit v1.2.3-58-ga151