Commit 3f8cafa4 authored by Jiong Wang's avatar Jiong Wang Committed by Alexei Starovoitov
Browse files

bpf: refactor propagate_liveness to eliminate code redundance 



Access to reg states were not factored out, the consequence is long code
for dereferencing them which made the indentation not good for reading.

This patch factor out these code so the core code in the loop could be
easier to follow.

Reviewed-by: default avatarJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: default avatarJiong Wang <jiong.wang@netronome.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 1b04aee7

kernel/bpf/verifier.c

+20 −14
Original line number Diff line number Diff line
@@ -6232,8 +6232,9 @@ static int propagate_liveness(struct bpf_verifier_env *env, 
			      const struct bpf_verifier_state *vstate,

			      struct bpf_verifier_state *vparent)

{

	int i, frame, err = 0;

	struct bpf_reg_state *state_reg, *parent_reg;

	struct bpf_func_state *state, *parent;

	int i, frame, err = 0;



	if (vparent->curframe != vstate->curframe) {

		WARN(1, "propagate_live: parent frame %d current frame %d\n",
@@ -6243,28 +6244,33 @@ static int propagate_liveness(struct bpf_verifier_env *env, 
	/* Propagate read liveness of registers... */

	BUILD_BUG_ON(BPF_REG_FP + 1 != MAX_BPF_REG);

	for (frame = 0; frame <= vstate->curframe; frame++) {

		parent = vparent->frame[frame];

		state = vstate->frame[frame];

		parent_reg = parent->regs;

		state_reg = state->regs;

		/* We don't need to worry about FP liveness, it's read-only */

		for (i = frame < vstate->curframe ? BPF_REG_6 : 0; i < BPF_REG_FP; i++) {

			if (vparent->frame[frame]->regs[i].live & REG_LIVE_READ)

			if (parent_reg[i].live & REG_LIVE_READ)

				continue;

			if (!(state_reg[i].live & REG_LIVE_READ))

				continue;

			if (vstate->frame[frame]->regs[i].live & REG_LIVE_READ) {

				err = mark_reg_read(env, &vstate->frame[frame]->regs[i],

						    &vparent->frame[frame]->regs[i]);

			err = mark_reg_read(env, &state_reg[i], &parent_reg[i]);

			if (err)

				return err;

		}

		}



		/* Propagate stack slots. */

		state = vstate->frame[frame];

		parent = vparent->frame[frame];

		for (i = 0; i < state->allocated_stack / BPF_REG_SIZE &&

			    i < parent->allocated_stack / BPF_REG_SIZE; i++) {

			if (parent->stack[i].spilled_ptr.live & REG_LIVE_READ)

			parent_reg = &parent->stack[i].spilled_ptr;

			state_reg = &state->stack[i].spilled_ptr;

			if (parent_reg->live & REG_LIVE_READ)

				continue;

			if (!(state_reg->live & REG_LIVE_READ))

				continue;

			if (state->stack[i].spilled_ptr.live & REG_LIVE_READ)

				mark_reg_read(env, &state->stack[i].spilled_ptr,

					      &parent->stack[i].spilled_ptr);

			err = mark_reg_read(env, state_reg, parent_reg);

			if (err)

				return err;

		}

	}

	return err;

CRA Git | Maintained and supported by SUSTech CRA and CCSE