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bpf: cleanup explored_states

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clean up explored_states to prep for introduction of hashtable
No functional changes.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Alexei Starovoitov 2019-05-21 20:17:05 -07:00 committed by Daniel Borkmann
parent 29c677c86a
commit 5d83902167
1 changed files with 20 additions and 9 deletions
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29
kernel/bpf/verifier.c
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@ -5437,6 +5437,17 @@ enum {
}; };
#define STATE_LIST_MARK ((struct bpf_verifier_state_list *) -1L) #define STATE_LIST_MARK ((struct bpf_verifier_state_list *) -1L)
static struct bpf_verifier_state_list **explored_state(
struct bpf_verifier_env *env,
int idx)
{
return &env->explored_states[idx];
}
static void init_explored_state(struct bpf_verifier_env *env, int idx)
{
env->explored_states[idx] = STATE_LIST_MARK;
}
/* t, w, e - match pseudo-code above: /* t, w, e - match pseudo-code above:
* t - index of current instruction * t - index of current instruction
@ -5462,7 +5473,7 @@ static int push_insn(int t, int w, int e, struct bpf_verifier_env *env)
if (e == BRANCH) if (e == BRANCH)
/* mark branch target for state pruning */ /* mark branch target for state pruning */
env->explored_states[w] = STATE_LIST_MARK; init_explored_state(env, w);
if (insn_state[w] == 0) { if (insn_state[w] == 0) {
/* tree-edge */ /* tree-edge */
@ -5530,9 +5541,9 @@ static int check_cfg(struct bpf_verifier_env *env)
else if (ret < 0) else if (ret < 0)
goto err_free; goto err_free;
if (t + 1 < insn_cnt) if (t + 1 < insn_cnt)
env->explored_states[t + 1] = STATE_LIST_MARK; init_explored_state(env, t + 1);
if (insns[t].src_reg == BPF_PSEUDO_CALL) { if (insns[t].src_reg == BPF_PSEUDO_CALL) {
env->explored_states[t] = STATE_LIST_MARK; init_explored_state(env, t);
ret = push_insn(t, t + insns[t].imm + 1, BRANCH, env); ret = push_insn(t, t + insns[t].imm + 1, BRANCH, env);
if (ret == 1) if (ret == 1)
goto peek_stack; goto peek_stack;
@ -5555,10 +5566,10 @@ static int check_cfg(struct bpf_verifier_env *env)
* after every call and jump * after every call and jump
*/ */
if (t + 1 < insn_cnt) if (t + 1 < insn_cnt)
env->explored_states[t + 1] = STATE_LIST_MARK; init_explored_state(env, t + 1);
} else { } else {
/* conditional jump with two edges */ /* conditional jump with two edges */
env->explored_states[t] = STATE_LIST_MARK; init_explored_state(env, t);
ret = push_insn(t, t + 1, FALLTHROUGH, env); ret = push_insn(t, t + 1, FALLTHROUGH, env);
if (ret == 1) if (ret == 1)
goto peek_stack; goto peek_stack;
@ -6006,7 +6017,7 @@ static void clean_live_states(struct bpf_verifier_env *env, int insn,
struct bpf_verifier_state_list *sl; struct bpf_verifier_state_list *sl;
int i; int i;
sl = env->explored_states[insn]; sl = *explored_state(env, insn);
if (!sl) if (!sl)
return; return;
@ -6365,7 +6376,7 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx)
struct bpf_verifier_state *cur = env->cur_state, *new; struct bpf_verifier_state *cur = env->cur_state, *new;
int i, j, err, states_cnt = 0; int i, j, err, states_cnt = 0;
pprev = &env->explored_states[insn_idx]; pprev = explored_state(env, insn_idx);
sl = *pprev; sl = *pprev;
if (!sl) if (!sl)
@ -6452,8 +6463,8 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx)
kfree(new_sl); kfree(new_sl);
return err; return err;
} }
new_sl->next = env->explored_states[insn_idx]; new_sl->next = *explored_state(env, insn_idx);
env->explored_states[insn_idx] = new_sl; *explored_state(env, insn_idx) = new_sl;
/* connect new state to parentage chain. Current frame needs all /* connect new state to parentage chain. Current frame needs all
* registers connected. Only r6 - r9 of the callers are alive (pushed * registers connected. Only r6 - r9 of the callers are alive (pushed
* to the stack implicitly by JITs) so in callers' frames connect just * to the stack implicitly by JITs) so in callers' frames connect just