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Commit 55e7f3b5 authored by Jiong Wang's avatar Jiong Wang Committed by Alexei Starovoitov
Browse files

bpf: factor out reg and stack slot propagation into "propagate_liveness_reg" 



After code refactor in previous patches, the propagation logic inside the
for loop in "propagate_liveness" becomes clear that they are good enough to
be factored out into a common function "propagate_liveness_reg".

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 3f8cafa4

kernel/bpf/verifier.c

+20 −10
Original line number Diff line number Diff line
@@ -6221,6 +6221,22 @@ static bool states_equal(struct bpf_verifier_env *env, 
	return true;

}



static int propagate_liveness_reg(struct bpf_verifier_env *env,

				  struct bpf_reg_state *reg,

				  struct bpf_reg_state *parent_reg)

{

	int err;



	if (parent_reg->live & REG_LIVE_READ || !(reg->live & REG_LIVE_READ))

		return 0;



	err = mark_reg_read(env, reg, parent_reg);

	if (err)

		return err;



	return 0;

}



/* A write screens off any subsequent reads; but write marks come from the

 * straight-line code between a state and its parent.  When we arrive at an

 * equivalent state (jump target or such) we didn't arrive by the straight-line
@@ -6250,11 +6266,8 @@ static int propagate_liveness(struct bpf_verifier_env *env, 
		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 (parent_reg[i].live & REG_LIVE_READ)

				continue;

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

				continue;

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

			err = propagate_liveness_reg(env, &state_reg[i],

						     &parent_reg[i]);

			if (err)

				return err;

		}
@@ -6264,11 +6277,8 @@ static int propagate_liveness(struct bpf_verifier_env *env, 
			    i < parent->allocated_stack / BPF_REG_SIZE; i++) {

			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;

			err = mark_reg_read(env, state_reg, parent_reg);

			err = propagate_liveness_reg(env, state_reg,

						     parent_reg);

			if (err)

				return err;

		}