bpf, arm64: Support signed div/mod instructions

Add JIT for signed div/mod instructions.

Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Florent Revest <revest@chromium.org>
Acked-by: Florent Revest <revest@chromium.org>
Link: https://lore.kernel.org/bpf/20230815154158.717901-7-xukuohai@huaweicloud.com

Author: Xu Kuohai

arch/arm64/net/bpf_jit.h

@@ -234,6 +234,7 @@
 #define A64_DATA2(sf, Rd, Rn, Rm, type) aarch64_insn_gen_data2(Rd, Rn, Rm, \
 	A64_VARIANT(sf), AARCH64_INSN_DATA2_##type)
 #define A64_UDIV(sf, Rd, Rn, Rm) A64_DATA2(sf, Rd, Rn, Rm, UDIV)
+#define A64_SDIV(sf, Rd, Rn, Rm) A64_DATA2(sf, Rd, Rn, Rm, SDIV)
 #define A64_LSLV(sf, Rd, Rn, Rm) A64_DATA2(sf, Rd, Rn, Rm, LSLV)
 #define A64_LSRV(sf, Rd, Rn, Rm) A64_DATA2(sf, Rd, Rn, Rm, LSRV)
 #define A64_ASRV(sf, Rd, Rn, Rm) A64_DATA2(sf, Rd, Rn, Rm, ASRV)

arch/arm64/net/bpf_jit_comp.c

@@ -828,11 +828,17 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
 		break;
 	case BPF_ALU | BPF_DIV | BPF_X:
 	case BPF_ALU64 | BPF_DIV | BPF_X:
-		emit(A64_UDIV(is64, dst, dst, src), ctx);
+		if (!off)
+			emit(A64_UDIV(is64, dst, dst, src), ctx);
+		else
+			emit(A64_SDIV(is64, dst, dst, src), ctx);
 		break;
 	case BPF_ALU | BPF_MOD | BPF_X:
 	case BPF_ALU64 | BPF_MOD | BPF_X:
-		emit(A64_UDIV(is64, tmp, dst, src), ctx);
+		if (!off)
+			emit(A64_UDIV(is64, tmp, dst, src), ctx);
+		else
+			emit(A64_SDIV(is64, tmp, dst, src), ctx);
 		emit(A64_MSUB(is64, dst, dst, tmp, src), ctx);
 		break;
 	case BPF_ALU | BPF_LSH | BPF_X:
@@ -959,12 +965,18 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
 	case BPF_ALU | BPF_DIV | BPF_K:
 	case BPF_ALU64 | BPF_DIV | BPF_K:
 		emit_a64_mov_i(is64, tmp, imm, ctx);
-		emit(A64_UDIV(is64, dst, dst, tmp), ctx);
+		if (!off)
+			emit(A64_UDIV(is64, dst, dst, tmp), ctx);
+		else
+			emit(A64_SDIV(is64, dst, dst, tmp), ctx);
 		break;
 	case BPF_ALU | BPF_MOD | BPF_K:
 	case BPF_ALU64 | BPF_MOD | BPF_K:
 		emit_a64_mov_i(is64, tmp2, imm, ctx);
-		emit(A64_UDIV(is64, tmp, dst, tmp2), ctx);
+		if (!off)
+			emit(A64_UDIV(is64, tmp, dst, tmp2), ctx);
+		else
+			emit(A64_SDIV(is64, tmp, dst, tmp2), ctx);
 		emit(A64_MSUB(is64, dst, dst, tmp, tmp2), ctx);
 		break;
 	case BPF_ALU | BPF_LSH | BPF_K: