commit 52954ff5050c83af36f6de76f6834c2068825699
author Patrick Rohr <prohr@google.com> Wed May 17 16:22:05 2023 -0700
committer Patrick Rohr <prohr@google.com> Thu May 18 14:08:37 2023 -0700
tree 566811604fd654457f4bcf43c24eba91c67d0045
parent 0d6edeef83505b4abf7a926c4d5189b23320b428

BpfRingbuf: Add support for 32 bit kernels

This change adds support for 32 bit kernels by capping mProducerPos to
4 bytes. mConsumerPos (which is written to by userspace) continues to
use 8 bytes. (This can be done because an entire page is allocated for
mConsumerPos to control access permissions). In a 32 bit kernel, that
means that the top order bits are just ignored. In addition, comparisons
in userspace only use the bottom 4 bytes to be bitness agnostic.

Test: atest BpfRingbufTest
Change-Id: I7fe6d9000a151512785f1aa2a53fa97d31967d19