kernel-patches
diff --git a/‎include/linux/bpf_verifier.h
Lines changed: 52 additions & 25 deletions b/‎include/linux/bpf_verifier.h
Lines changed: 52 additions & 25 deletions
@@ -344,7 +344,7 @@ struct bpf_func_state {
 
 #define MAX_CALL_FRAMES 8
 
-/* instruction history flags, used in bpf_insn_hist_entry.flags field */
+/* instruction history flags, used in bpf_jmp_history_entry.flags field */
 enum {
 	/* instruction references stack slot through PTR_TO_STACK register;
 	 * we also store stack's frame number in lower 3 bits (MAX_CALL_FRAMES is 8)
@@ -366,7 +366,7 @@ enum {
 static_assert(INSN_F_FRAMENO_MASK + 1 >= MAX_CALL_FRAMES);
 static_assert(INSN_F_SPI_MASK + 1 >= MAX_BPF_STACK / 8);
 
-struct bpf_insn_hist_entry {
+struct bpf_jmp_history_entry {
 	u32 idx;
 	/* insn idx can't be bigger than 1 million */
 	u32 prev_idx : 20;
@@ -449,32 +449,20 @@ struct bpf_verifier_state {
 	/* first and last insn idx of this verifier state */
 	u32 first_insn_idx;
 	u32 last_insn_idx;
-	/* If this state is a part of states loop this field points to some
-	 * parent of this state such that:
-	 * - it is also a member of the same states loop;
-	 * - DFS states traversal starting from initial state visits loop_entry
-	 *   state before this state.
-	 * Used to compute topmost loop entry for state loops.
-	 * State loops might appear because of open coded iterators logic.
-	 * See get_loop_entry() for more information.
+	/* if this state is a backedge state then equal_state
+	 * records cached state to which this state is equal.
 	 */
-	struct bpf_verifier_state *loop_entry;
-	/* Sub-range of env->insn_hist[] corresponding to this state's
-	 * instruction history.
-	 * Backtracking is using it to go from last to first.
-	 * For most states instruction history is short, 0-3 instructions.
+	struct bpf_verifier_state *equal_state;
+	/* jmp history recorded from first to last.
+	 * backtracking is using it to go from last to first.
+	 * For most states jmp_history_cnt is [0-3].
 	 * For loops can go up to ~40.
 	 */
-	u32 insn_hist_start;
-	u32 insn_hist_end;
+	struct bpf_jmp_history_entry *jmp_history;
+	u32 jmp_history_cnt;
 	u32 dfs_depth;
 	u32 callback_unroll_depth;
 	u32 may_goto_depth;
-	/* If this state was ever pointed-to by other state's loop_entry field
-	 * this flag would be set to true. Used to avoid freeing such states
-	 * while they are still in use.
-	 */
-	u32 used_as_loop_entry;
 };
 
 #define bpf_get_spilled_reg(slot, frame, mask)				\
@@ -610,6 +598,11 @@ struct bpf_insn_aux_data {
 	 * accepts callback function as a parameter.
 	 */
 	bool calls_callback;
+	/*
+	 * CFG strongly connected component this instruction belongs to,
+	 * zero if it is a singleton SCC.
+	 */
+	u32 scc;
 	/* registers alive before this instruction. */
 	u16 live_regs_before;
 };
@@ -719,6 +712,38 @@ struct bpf_idset {
 	u32 ids[BPF_ID_MAP_SIZE];
 };
 
+/* see verifier.c:compute_scc_callchain() */
+struct bpf_scc_callchain {
+	/* call sites from bpf_verifier_state->frame[*]->callsite leading to this SCC */
+	u32 callsites[MAX_CALL_FRAMES - 1];
+	/* last frame in a chain is identified by SCC id */
+	u32 scc;
+};
+
+/* verifier state waiting for propagate_backedges() */
+struct bpf_scc_backedge {
+	struct bpf_scc_backedge *next;
+	struct bpf_verifier_state state;
+};
+
+struct bpf_scc_visit {
+	struct bpf_scc_callchain callchain;
+	/* first state in current verification path that entered SCC
+	 * identified by the callchain
+	 */
+	struct bpf_verifier_state *entry_state;
+	struct bpf_scc_backedge *backedges; /* list of backedges */
+	u32 num_backedges;
+};
+
+/* An array of bpf_scc_visit structs sharing tht same bpf_scc_callchain->scc
+ * but having different bpf_scc_callchain->callsites.
+ */
+struct bpf_scc_info {
+	u32 num_visits;
+	struct bpf_scc_visit visits[];
+};
+
 /* single container for all structs
  * one verifier_env per bpf_check() call
  */
@@ -776,9 +801,7 @@ struct bpf_verifier_env {
 		int cur_postorder;
 	} cfg;
 	struct backtrack_state bt;
-	struct bpf_insn_hist_entry *insn_hist;
-	struct bpf_insn_hist_entry *cur_hist_ent;
-	u32 insn_hist_cap;
+	struct bpf_jmp_history_entry *cur_hist_ent;
 	u32 pass_cnt; /* number of times do_check() was called */
 	u32 subprog_cnt;
 	/* number of instructions analyzed by the verifier */
@@ -800,6 +823,7 @@ struct bpf_verifier_env {
 	u32 longest_mark_read_walk;
 	u32 free_list_size;
 	u32 explored_states_size;
+	u32 num_backedges;
 	bpfptr_t fd_array;
 
 	/* bit mask to keep track of whether a register has been accessed
@@ -817,6 +841,9 @@ struct bpf_verifier_env {
 	char tmp_str_buf[TMP_STR_BUF_LEN];
 	struct bpf_insn insn_buf[INSN_BUF_SIZE];
 	struct bpf_insn epilogue_buf[INSN_BUF_SIZE];
+	/* array of pointers to bpf_scc_info indexed by SCC id */
+	struct bpf_scc_info **scc_info;
+	u32 scc_cnt;
 };
 
 static inline struct bpf_func_info_aux *subprog_aux(struct bpf_verifier_env *env, int subprog)