Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 25 insertions, 0 deletions

diff --git a/Documentation/bpf/standardization/abi.rst b/Documentation/bpf/standardization/abi.rst
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+.. 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.