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