1# zygote-start is what officially starts netd (see //system/core/rootdir/init.rc)
2# However, on some hardware it's started from post-fs-data as well, which is just
3# a tad earlier.  There's no benefit to that though, since on 4.9+ P+ devices netd
4# will just block until bpfloader finishes and sets the bpf.progs_loaded property.
5#
6# It is important that we start bpfloader after:
7#   - /sys/fs/bpf is already mounted,
8#   - apex (incl. rollback) is initialized (so that in the future we can load bpf
9#     programs shipped as part of apex mainline modules)
10#   - logd is ready for us to log stuff
11#
12# At the same time we want to be as early as possible to reduce races and thus
13# failures (before memory is fragmented, and cpu is busy running tons of other
14# stuff) and we absolutely want to be before netd and the system boot slot is
15# considered to have booted successfully.
16#
17on load_bpf_programs
18    # Enable the eBPF JIT -- but do note that on 64-bit kernels it is likely
19    # already force enabled by the kernel config option BPF_JIT_ALWAYS_ON
20    write /proc/sys/net/core/bpf_jit_enable 1
21    # Enable JIT kallsyms export for privileged users only
22    write /proc/sys/net/core/bpf_jit_kallsyms 1
23    exec_start bpfloader
24
25service bpfloader /system/bin/bpfloader
26    capabilities CHOWN SYS_ADMIN NET_ADMIN
27    #
28    # Set RLIMIT_MEMLOCK to 1GiB for bpfloader
29    #
30    # Actually only 8MiB would be needed if bpfloader ran as its own uid.
31    #
32    # However, while the rlimit is per-thread, the accounting is system wide.
33    # So, for example, if the graphics stack has already allocated 10MiB of
34    # memlock data before bpfloader even gets a chance to run, it would fail
35    # if its memlock rlimit is only 8MiB - since there would be none left for it.
36    #
37    # bpfloader succeeding is critical to system health, since a failure will
38    # cause netd crashloop and thus system server crashloop... and the only
39    # recovery is a full kernel reboot.
40    #
41    # We've had issues where devices would sometimes (rarely) boot into
42    # a crashloop because bpfloader would occasionally lose a boot time
43    # race against the graphics stack's boot time locked memory allocation.
44    #
45    # Thus bpfloader's memlock has to be 8MB higher then the locked memory
46    # consumption of the root uid anywhere else in the system...
47    # But we don't know what that is for all possible devices...
48    #
49    # Ideally, we'd simply grant bpfloader the IPC_LOCK capability and it
50    # would simply ignore it's memlock rlimit... but it turns that this
51    # capability is not even checked by the kernel's bpf system call.
52    #
53    # As such we simply use 1GiB as a reasonable approximation of infinity.
54    #
55    rlimit memlock 1073741824 1073741824
56    oneshot
57    reboot_on_failure reboot,bpfloader-failed
58    # we're not really updatable, but want to be able to load bpf programs shipped in apexes
59    updatable
60