bpf: refactor "check_reg_arg" to eliminate code redundancy (c342dc10) · Commits · 戴 / test

kernel/bpf/verifier.c

+8 −6

Original line number	Diff line number	Diff line
		@@ -1177,30 +1177,32 @@ static int check_reg_arg(struct bpf_verifier_env *env, u32 regno,
		{
		struct bpf_verifier_state *vstate = env->cur_state;
		struct bpf_func_state *state = vstate->frame[vstate->curframe];
		struct bpf_reg_state *regs = state->regs;
		struct bpf_reg_state reg, regs = state->regs;

		if (regno >= MAX_BPF_REG) {
		verbose(env, "R%d is invalid\n", regno);
		return -EINVAL;
		}

		reg = &regs[regno];
		if (t == SRC_OP) {
		/* check whether register used as source operand can be read */
		if (regs[regno].type == NOT_INIT) {
		if (reg->type == NOT_INIT) {
		verbose(env, "R%d !read_ok\n", regno);
		return -EACCES;
		}
		/* We don't need to worry about FP liveness because it's read-only */
		if (regno != BPF_REG_FP)
		return mark_reg_read(env, &regs[regno],
		regs[regno].parent);
		if (regno == BPF_REG_FP)
		return 0;

		return mark_reg_read(env, reg, reg->parent);
		} else {
		/* check whether register used as dest operand can be written to */
		if (regno == BPF_REG_FP) {
		verbose(env, "frame pointer is read only\n");
		return -EACCES;
		}
		regs[regno].live \|= REG_LIVE_WRITTEN;
		reg->live \|= REG_LIVE_WRITTEN;
		if (t == DST_OP)
		mark_reg_unknown(env, regs, regno);
		}