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