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Commit 2dc6b100 authored by Jiong Wang's avatar Jiong Wang Committed by Alexei Starovoitov
Browse files

bpf: interpreter support BPF_ALU | BPF_ARSH 



This patch implements interpreting BPF_ALU | BPF_ARSH. Do arithmetic right
shift on low 32-bit sub-register, and zero the high 32 bits.

Reviewed-by: default avatarJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: default avatarJiong Wang <jiong.wang@netronome.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 84708c13

kernel/bpf/core.c

+30 −22
Original line number Diff line number Diff line
@@ -942,6 +942,7 @@ EXPORT_SYMBOL_GPL(__bpf_call_base); 
	INSN_3(ALU, XOR,  X),			\

	INSN_3(ALU, MUL,  X),			\

	INSN_3(ALU, MOV,  X),			\

	INSN_3(ALU, ARSH, X),			\

	INSN_3(ALU, DIV,  X),			\

	INSN_3(ALU, MOD,  X),			\

	INSN_2(ALU, NEG),			\
@@ -957,6 +958,7 @@ EXPORT_SYMBOL_GPL(__bpf_call_base); 
	INSN_3(ALU, XOR,  K),			\

	INSN_3(ALU, MUL,  K),			\

	INSN_3(ALU, MOV,  K),			\

	INSN_3(ALU, ARSH, K),			\

	INSN_3(ALU, DIV,  K),			\

	INSN_3(ALU, MOD,  K),			\

	/* 64 bit ALU operations. */		\
@@ -1137,6 +1139,12 @@ static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn, u64 *stack) 
		DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32;

		insn++;

		CONT;

	ALU_ARSH_X:

		DST = (u64) (u32) ((*(s32 *) &DST) >> SRC);

		CONT;

	ALU_ARSH_K:

		DST = (u64) (u32) ((*(s32 *) &DST) >> IMM);

		CONT;

	ALU64_ARSH_X:

		(*(s64 *) &DST) >>= SRC;

		CONT;