riscv, bpf: Add support for far jumps and exits (33203c02) · Commits · 戴 / test

arch/riscv/net/bpf_jit_comp.c

+17 −20

Original line number	Diff line number	Diff line
		@@ -496,16 +496,6 @@ static int is_12b_check(int off, int insn)
		return 0;
		}

		static int is_21b_check(int off, int insn)
		{
		if (!is_21b_int(off)) {
		pr_err("bpf-jit: insn=%d 21b < offset=%d not supported yet!\n",
		insn, (int)off);
		return -1;
		}
		return 0;
		}

		static void emit_imm(u8 rd, s64 val, struct rv_jit_context *ctx)
		{
		/* Note that the immediate from the add is sign-extended,
		@@ -820,6 +810,21 @@ static void emit_sext_32_rd(u8 rd, struct rv_jit_context ctx)
		*rd = RV_REG_T2;
		}

		static void emit_jump_and_link(u8 rd, int rvoff, struct rv_jit_context *ctx)
		{
		s64 upper, lower;

		if (is_21b_int(rvoff)) {
		emit(rv_jal(rd, rvoff >> 1), ctx);
		return;
		}

		upper = (rvoff + (1 << 11)) >> 12;
		lower = rvoff & 0xfff;
		emit(rv_auipc(RV_REG_T1, upper), ctx);
		emit(rv_jalr(rd, RV_REG_T1, lower), ctx);
		}

		static bool is_signed_bpf_cond(u8 cond)
		{
		return cond == BPF_JSGT \|\| cond == BPF_JSLT \|\|
		@@ -1101,13 +1106,7 @@ out_be:
		/* JUMP off */
		case BPF_JMP \| BPF_JA:
		rvoff = rv_offset(i, off, ctx);
		if (!is_21b_int(rvoff)) {
		pr_err("bpf-jit: insn=%d offset=%d not supported yet!\n",
		i, rvoff);
		return -1;
		}

		emit(rv_jal(RV_REG_ZERO, rvoff >> 1), ctx);
		emit_jump_and_link(RV_REG_ZERO, rvoff, ctx);
		break;

		/* IF (dst COND src) JUMP off */
		@@ -1245,9 +1244,7 @@ out_be:
		break;

		rvoff = epilogue_offset(ctx);
		if (is_21b_check(rvoff, i))
		return -1;
		emit(rv_jal(RV_REG_ZERO, rvoff >> 1), ctx);
		emit_jump_and_link(RV_REG_ZERO, rvoff, ctx);
		break;

		/* dst = imm64 */