From f5c27da4e3c8a2e42fb4f41a0c685debcb9af294 Mon Sep 17 00:00:00 2001 From: Benjamin Tissoires Date: Thu, 3 Nov 2022 16:57:44 +0100 Subject: HID: initial BPF implementation Declare an entry point that can use fmod_ret BPF programs, and also an API to access and change the incoming data. A simpler implementation would consist in just calling hid_bpf_device_event() for any incoming event and let users deal with the fact that they will be called for any event of any device. The goal of HID-BPF is to partially replace drivers, so this situation can be problematic because we might have programs which will step on each other toes. For that, we add a new API hid_bpf_attach_prog() that can be called from a syscall and we manually deal with a jump table in hid-bpf. Whenever we add a program to the jump table (in other words, when we attach a program to a HID device), we keep the number of time we added this program in the jump table so we can release it whenever there are no other users. HID devices have an RCU protected list of available programs in the jump table, and those programs are called one after the other thanks to bpf_tail_call(). To achieve the detection of users losing their fds on the programs we attached, we add 2 tracing facilities on bpf_prog_release() (for when a fd is closed) and bpf_free_inode() (for when a pinned program gets unpinned). Reviewed-by: Greg Kroah-Hartman Signed-off-by: Benjamin Tissoires Signed-off-by: Jiri Kosina --- drivers/hid/Makefile | 2 ++ 1 file changed, 2 insertions(+) (limited to 'drivers/hid/Makefile') diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile index e8014c1a2f8b..c45b516eb767 100644 --- a/drivers/hid/Makefile +++ b/drivers/hid/Makefile @@ -5,6 +5,8 @@ hid-y := hid-core.o hid-input.o hid-quirks.o hid-$(CONFIG_DEBUG_FS) += hid-debug.o +obj-$(CONFIG_HID_BPF) += bpf/ + obj-$(CONFIG_HID) += hid.o obj-$(CONFIG_UHID) += uhid.o -- cgit v1.2.3