riscv, bpf: Add support for far branching when emitting tail call (29d92edd) · Commits · 戴 / test

arch/riscv/net/bpf_jit_comp.c

+3 −19

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_13b_check(int off, int insn)
		{
		if (!is_13b_int(off)) {
		pr_err("bpf-jit: insn=%d 13b < offset=%d not supported yet!\n",
		insn, (int)off);
		return -1;
		}
		return 0;
		}

		static int is_21b_check(int off, int insn)
		{
		if (!is_21b_int(off)) {
		@@ -744,18 +734,14 @@ static int emit_bpf_tail_call(int insn, struct rv_jit_context *ctx)
		return -1;
		emit(rv_lwu(RV_REG_T1, off, RV_REG_A1), ctx);
		off = (tc_ninsn - (ctx->ninsns - start_insn)) << 2;
		if (is_13b_check(off, insn))
		return -1;
		emit(rv_bgeu(RV_REG_A2, RV_REG_T1, off >> 1), ctx);
		emit_branch(BPF_JGE, RV_REG_A2, RV_REG_T1, off, ctx);

		/* if (--TCC < 0)
		* goto out;
		*/
		emit(rv_addi(RV_REG_T1, tcc, -1), ctx);
		off = (tc_ninsn - (ctx->ninsns - start_insn)) << 2;
		if (is_13b_check(off, insn))
		return -1;
		emit(rv_blt(RV_REG_T1, RV_REG_ZERO, off >> 1), ctx);
		emit_branch(BPF_JSLT, RV_REG_T1, RV_REG_ZERO, off, ctx);

		/* prog = array->ptrs[index];
		* if (!prog)
		@@ -768,9 +754,7 @@ static int emit_bpf_tail_call(int insn, struct rv_jit_context *ctx)
		return -1;
		emit(rv_ld(RV_REG_T2, off, RV_REG_T2), ctx);
		off = (tc_ninsn - (ctx->ninsns - start_insn)) << 2;
		if (is_13b_check(off, insn))
		return -1;
		emit(rv_beq(RV_REG_T2, RV_REG_ZERO, off >> 1), ctx);
		emit_branch(BPF_JEQ, RV_REG_T2, RV_REG_ZERO, off, ctx);

		/* goto (prog->bpf_func + 4); /
		off = offsetof(struct bpf_prog, bpf_func);