Commit bb0a1d6b authored by Xu Kuohai's avatar Xu Kuohai Committed by Daniel Borkmann
Browse files

bpf, arm64: Support sign-extension mov instructions 



Add JIT support for BPF sign-extension mov instructions with arm64
SXTB/SXTH/SXTW instructions.

Signed-off-by: default avatarXu Kuohai <xukuohai@huawei.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Tested-by: default avatarFlorent Revest <revest@chromium.org>
Acked-by: default avatarFlorent Revest <revest@chromium.org>
Link: https://lore.kernel.org/bpf/20230815154158.717901-4-xukuohai@huaweicloud.com
parent cc88f540

arch/arm64/net/bpf_jit.h

+5 −0
Original line number Diff line number Diff line
@@ -192,6 +192,11 @@ 
#define A64_UXTH(sf, Rd, Rn) A64_UBFM(sf, Rd, Rn, 0, 15)

#define A64_UXTW(sf, Rd, Rn) A64_UBFM(sf, Rd, Rn, 0, 31)



/* Sign extend */

#define A64_SXTB(sf, Rd, Rn) A64_SBFM(sf, Rd, Rn, 0, 7)

#define A64_SXTH(sf, Rd, Rn) A64_SBFM(sf, Rd, Rn, 0, 15)

#define A64_SXTW(sf, Rd, Rn) A64_SBFM(sf, Rd, Rn, 0, 31)



/* Move wide (immediate) */

#define A64_MOVEW(sf, Rd, imm16, shift, type) \

	aarch64_insn_gen_movewide(Rd, imm16, shift, \

arch/arm64/net/bpf_jit_comp.c

+14 −1
Original line number Diff line number Diff line
@@ -786,8 +786,21 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, 
	/* dst = src */

	case BPF_ALU | BPF_MOV | BPF_X:

	case BPF_ALU64 | BPF_MOV | BPF_X:

		switch (insn->off) {

		case 0:

			emit(A64_MOV(is64, dst, src), ctx);

			break;

		case 8:

			emit(A64_SXTB(is64, dst, src), ctx);

			break;

		case 16:

			emit(A64_SXTH(is64, dst, src), ctx);

			break;

		case 32:

			emit(A64_SXTW(is64, dst, src), ctx);

			break;

		}

		break;

	/* dst = dst OP src */

	case BPF_ALU | BPF_ADD | BPF_X:

	case BPF_ALU64 | BPF_ADD | BPF_X: