bpf: Consistently use reg_state() for register access in the verifier

Replace the pattern of declaring a local regs array from cur_regs()
and then indexing into it with the more concise reg_state() helper.
This simplifies the code by eliminating intermediate variables and
makes register access more consistent throughout the verifier.

Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20260113134826.2214860-1-mykyta.yatsenko5@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 19 insertions, 23 deletions

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 53635ea2e41b..02a43cafbb25 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -5654,8 +5654,8 @@ static int check_stack_write(struct bpf_verifier_env *env,
 static int check_map_access_type(struct bpf_verifier_env *env, u32 regno,
 				 int off, int size, enum bpf_access_type type)
 {
-	struct bpf_reg_state *regs = cur_regs(env);
-	struct bpf_map *map = regs[regno].map_ptr;
+	struct bpf_reg_state *reg = reg_state(env, regno);
+	struct bpf_map *map = reg->map_ptr;
 	u32 cap = bpf_map_flags_to_cap(map);
 
 	if (type == BPF_WRITE && !(cap & BPF_MAP_CAN_WRITE)) {
@@ -6168,8 +6168,7 @@ static bool may_access_direct_pkt_data(struct bpf_verifier_env *env,
 static int check_packet_access(struct bpf_verifier_env *env, u32 regno, int off,
 			       int size, bool zero_size_allowed)
 {
-	struct bpf_reg_state *regs = cur_regs(env);
-	struct bpf_reg_state *reg = &regs[regno];
+	struct bpf_reg_state *reg = reg_state(env, regno);
 	int err;
 
 	/* We may have added a variable offset to the packet pointer; but any
@@ -6256,8 +6255,7 @@ static int check_sock_access(struct bpf_verifier_env *env, int insn_idx,
 			     u32 regno, int off, int size,
 			     enum bpf_access_type t)
 {
-	struct bpf_reg_state *regs = cur_regs(env);
-	struct bpf_reg_state *reg = &regs[regno];
+	struct bpf_reg_state *reg = reg_state(env, regno);
 	struct bpf_insn_access_aux info = {};
 	bool valid;
 
@@ -7453,8 +7451,7 @@ static int check_stack_access_within_bounds(
 		int regno, int off, int access_size,
 		enum bpf_access_type type)
 {
-	struct bpf_reg_state *regs = cur_regs(env);
-	struct bpf_reg_state *reg = regs + regno;
+	struct bpf_reg_state *reg = reg_state(env, regno);
 	struct bpf_func_state *state = func(env, reg);
 	s64 min_off, max_off;
 	int err;
@@ -8408,7 +8405,7 @@ static int process_spin_lock(struct bpf_verifier_env *env, int regno, int flags)
 {
 	bool is_lock = flags & PROCESS_SPIN_LOCK, is_res_lock = flags & PROCESS_RES_LOCK;
 	const char *lock_str = is_res_lock ? "bpf_res_spin" : "bpf_spin";
-	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
+	struct bpf_reg_state *reg = reg_state(env, regno);
 	struct bpf_verifier_state *cur = env->cur_state;
 	bool is_const = tnum_is_const(reg->var_off);
 	bool is_irq = flags & PROCESS_LOCK_IRQ;
@@ -8524,7 +8521,7 @@ static int process_spin_lock(struct bpf_verifier_env *env, int regno, int flags)
 static int check_map_field_pointer(struct bpf_verifier_env *env, u32 regno,
 				   enum btf_field_type field_type)
 {
-	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
+	struct bpf_reg_state *reg = reg_state(env, regno);
 	bool is_const = tnum_is_const(reg->var_off);
 	struct bpf_map *map = reg->map_ptr;
 	u64 val = reg->var_off.value;
@@ -8571,7 +8568,7 @@ static int check_map_field_pointer(struct bpf_verifier_env *env, u32 regno,
 static int process_timer_func(struct bpf_verifier_env *env, int regno,
 			      struct bpf_call_arg_meta *meta)
 {
-	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
+	struct bpf_reg_state *reg = reg_state(env, regno);
 	struct bpf_map *map = reg->map_ptr;
 	int err;
 
@@ -8595,7 +8592,7 @@ static int process_timer_func(struct bpf_verifier_env *env, int regno,
 static int process_wq_func(struct bpf_verifier_env *env, int regno,
 			   struct bpf_kfunc_call_arg_meta *meta)
 {
-	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
+	struct bpf_reg_state *reg = reg_state(env, regno);
 	struct bpf_map *map = reg->map_ptr;
 	int err;
 
@@ -8616,7 +8613,7 @@ static int process_wq_func(struct bpf_verifier_env *env, int regno,
 static int process_task_work_func(struct bpf_verifier_env *env, int regno,
 				  struct bpf_kfunc_call_arg_meta *meta)
 {
-	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
+	struct bpf_reg_state *reg = reg_state(env, regno);
 	struct bpf_map *map = reg->map_ptr;
 	int err;
 
@@ -8636,7 +8633,7 @@ static int process_task_work_func(struct bpf_verifier_env *env, int regno,
 static int process_kptr_func(struct bpf_verifier_env *env, int regno,
 			     struct bpf_call_arg_meta *meta)
 {
-	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
+	struct bpf_reg_state *reg = reg_state(env, regno);
 	struct btf_field *kptr_field;
 	struct bpf_map *map_ptr;
 	struct btf_record *rec;
@@ -8709,7 +8706,7 @@ static int process_kptr_func(struct bpf_verifier_env *env, int regno,
 static int process_dynptr_func(struct bpf_verifier_env *env, int regno, int insn_idx,
 			       enum bpf_arg_type arg_type, int clone_ref_obj_id)
 {
-	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
+	struct bpf_reg_state *reg = reg_state(env, regno);
 	int err;
 
 	if (reg->type != PTR_TO_STACK && reg->type != CONST_PTR_TO_DYNPTR) {
@@ -8829,7 +8826,7 @@ static bool is_kfunc_arg_iter(struct bpf_kfunc_call_arg_meta *meta, int arg_idx,
 static int process_iter_arg(struct bpf_verifier_env *env, int regno, int insn_idx,
 			    struct bpf_kfunc_call_arg_meta *meta)
 {
-	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
+	struct bpf_reg_state *reg = reg_state(env, regno);
 	const struct btf_type *t;
 	int spi, err, i, nr_slots, btf_id;
 
@@ -9301,7 +9298,7 @@ static int check_reg_type(struct bpf_verifier_env *env, u32 regno,
 			  const u32 *arg_btf_id,
 			  struct bpf_call_arg_meta *meta)
 {
-	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
+	struct bpf_reg_state *reg = reg_state(env, regno);
 	enum bpf_reg_type expected, type = reg->type;
 	const struct bpf_reg_types *compatible;
 	int i, j;
@@ -9714,7 +9711,7 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg,
 			  int insn_idx)
 {
 	u32 regno = BPF_REG_1 + arg;
-	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
+	struct bpf_reg_state *reg = reg_state(env, regno);
 	enum bpf_arg_type arg_type = fn->arg_type[arg];
 	enum bpf_reg_type type = reg->type;
 	u32 *arg_btf_id = NULL;
@@ -11247,7 +11244,7 @@ record_func_key(struct bpf_verifier_env *env, struct bpf_call_arg_meta *meta,
 		int func_id, int insn_idx)
 {
 	struct bpf_insn_aux_data *aux = &env->insn_aux_data[insn_idx];
-	struct bpf_reg_state *regs = cur_regs(env), *reg;
+	struct bpf_reg_state *reg;
 	struct bpf_map *map = meta->map_ptr;
 	u64 val, max;
 	int err;
@@ -11259,7 +11256,7 @@ record_func_key(struct bpf_verifier_env *env, struct bpf_call_arg_meta *meta,
 		return -EINVAL;
 	}
 
-	reg = &regs[BPF_REG_3];
+	reg = reg_state(env, BPF_REG_3);
 	val = reg->var_off.value;
 	max = map->max_entries;
 
@@ -11405,8 +11402,7 @@ static struct bpf_insn_aux_data *cur_aux(const struct bpf_verifier_env *env)
 
 static bool loop_flag_is_zero(struct bpf_verifier_env *env)
 {
-	struct bpf_reg_state *regs = cur_regs(env);
-	struct bpf_reg_state *reg = &regs[BPF_REG_4];
+	struct bpf_reg_state *reg = reg_state(env, BPF_REG_4);
 	bool reg_is_null = register_is_null(reg);
 
 	if (reg_is_null)
@@ -12668,7 +12664,7 @@ static int process_kf_arg_ptr_to_btf_id(struct bpf_verifier_env *env,
 static int process_irq_flag(struct bpf_verifier_env *env, int regno,
 			     struct bpf_kfunc_call_arg_meta *meta)
 {
-	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
+	struct bpf_reg_state *reg = reg_state(env, regno);
 	int err, kfunc_class = IRQ_NATIVE_KFUNC;
 	bool irq_save;