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

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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: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Jiong Wang 2019-04-12 22:59:36 +01:00 committed by Alexei Starovoitov
parent 3f8cafa413
commit 55e7f3b5ac
1 changed files with 20 additions and 10 deletions
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30
kernel/bpf/verifier.c
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@ -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;
}