28 lines
968 B
ReStructuredText
28 lines
968 B
ReStructuredText
.. contents::
|
|
.. sectnum::
|
|
|
|
===================================================
|
|
BPF ABI Recommended Conventions and Guidelines v1.0
|
|
===================================================
|
|
|
|
This is version 1.0 of an informational document containing recommended
|
|
conventions and guidelines for producing portable BPF program binaries.
|
|
|
|
Registers and calling convention
|
|
================================
|
|
|
|
BPF has 10 general purpose registers and a read-only frame pointer register,
|
|
all of which are 64-bits wide.
|
|
|
|
The BPF calling convention is defined as:
|
|
|
|
* R0: return value from function calls, and exit value for BPF programs
|
|
* R1 - R5: arguments for function calls
|
|
* R6 - R9: callee saved registers that function calls will preserve
|
|
* R10: read-only frame pointer to access stack
|
|
|
|
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``.
|