From 5ca5889b971ff65cd6843abb03d763e2886cedeb Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Thu, 10 Aug 2017 01:39:55 +0200 Subject: bpf: add BPF_J{LT,LE,SLT,SLE} instructions Currently, eBPF only understands BPF_JGT (>), BPF_JGE (>=), BPF_JSGT (s>), BPF_JSGE (s>=) instructions, this means that particularly *JLT/*JLE counterparts involving immediates need to be rewritten from e.g. X < [IMM] by swapping arguments into [IMM] > X, meaning the immediate first is required to be loaded into a register Y := [IMM], such that then we can compare with Y > X. Note that the destination operand is always required to be a register. This has the downside of having unnecessarily increased register pressure, meaning complex program would need to spill other registers temporarily to stack in order to obtain an unused register for the [IMM]. Loading to registers will thus also affect state pruning since we need to account for that register use and potentially those registers that had to be spilled/filled again. As a consequence slightly more stack space might have been used due to spilling, and BPF programs are a bit longer due to extra code involving the register load and potentially required spill/fills. Thus, add BPF_JLT (<), BPF_JLE (<=), BPF_JSLT (s<), BPF_JSLE (s<=) counterparts to the eBPF instruction set. Modifying LLVM to remove the NegateCC() workaround in a PoC patch at [1] and allowing it to also emit the new instructions resulted in cilium's BPF programs that are injected into the fast-path to have a reduced program length in the range of 2-3% (e.g. accumulated main and tail call sections from one of the object file reduced from 4864 to 4729 insns), reduced complexity in the range of 10-30% (e.g. accumulated sections reduced in one of the cases from 116432 to 88428 insns), and reduced stack usage in the range of 1-5% (e.g. accumulated sections from one of the object files reduced from 824 to 784b). The modification for LLVM will be incorporated in a backwards compatible way. Plan is for LLVM to have i) a target specific option to offer a possibility to explicitly enable the extension by the user (as we have with -m target specific extensions today for various CPU insns), and ii) have the kernel checked for presence of the extensions and enable them transparently when the user is selecting more aggressive options such as -march=native in a bpf target context. (Other frontends generating BPF byte code, e.g. ply can probe the kernel directly for its code generation.) [1] https://github.com/borkmann/llvm/tree/bpf-insns Change-Id: Ic56500aaeaf5f3ebdfda094ad6ef4666c82e18c5 Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- include/uapi/linux/bpf.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include/uapi/linux') diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index bbbf36a963e6..4f415fcb2006 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -30,9 +30,14 @@ #define BPF_FROM_LE BPF_TO_LE #define BPF_FROM_BE BPF_TO_BE +/* jmp encodings */ #define BPF_JNE 0x50 /* jump != */ +#define BPF_JLT 0xa0 /* LT is unsigned, '<' */ +#define BPF_JLE 0xb0 /* LE is unsigned, '<=' */ #define BPF_JSGT 0x60 /* SGT is signed '>', GT in x86 */ #define BPF_JSGE 0x70 /* SGE is signed '>=', GE in x86 */ +#define BPF_JSLT 0xc0 /* SLT is signed, '<' */ +#define BPF_JSLE 0xd0 /* SLE is signed, '<=' */ #define BPF_CALL 0x80 /* function call */ #define BPF_EXIT 0x90 /* function return */ -- cgit v1.2.3 From b04baa6223d275019e028c83e815fccb6616b06e Mon Sep 17 00:00:00 2001 From: Han Wang <416810799@qq.com> Date: Sat, 19 Mar 2022 08:17:00 +0100 Subject: input: Drop INPUT_PROP_NO_DUMMY_RELEASE bit * INPUT_PROP_NO_DUMMY_RELEASE definition in this kernel collides with INPUT_PROP_ACCELEROMETER definition in bionic and upstream kernel. As a result, Android recognizes normal input devices like accelerometers and causes strange behaviors. There are no references to this bit in userspace and it is not in 4.9+ kernels, so let's drop this CAF jank. Change-Id: Id9b4ec8d31470e663f533249c4bc4b9e94fd38be --- include/uapi/linux/input.h | 1 - 1 file changed, 1 deletion(-) (limited to 'include/uapi/linux') diff --git a/include/uapi/linux/input.h b/include/uapi/linux/input.h index 7a89b7b62ab8..f6a44010e84a 100644 --- a/include/uapi/linux/input.h +++ b/include/uapi/linux/input.h @@ -181,7 +181,6 @@ struct input_mask { #define INPUT_PROP_SEMI_MT 0x03 /* touch rectangle only */ #define INPUT_PROP_TOPBUTTONPAD 0x04 /* softbuttons at top of pad */ #define INPUT_PROP_POINTING_STICK 0x05 /* is a pointing stick */ -#define INPUT_PROP_NO_DUMMY_RELEASE 0x06 /* no dummy event */ #define INPUT_PROP_MAX 0x1f #define INPUT_PROP_CNT (INPUT_PROP_MAX + 1) -- cgit v1.2.3