No code change but is a preparatory patch for being able to declare async callbacks from bpf kfuncs.
Signed-off-by: Benjamin Tissoires bentiss@kernel.org
---
This is an RFC, and is not meant to be fully reviewed/applied as it is. I'm posting this to show what I wanted to explain in https://lore.kernel.org/bpf/mhkzkf4e23uvljtmwizwcxyuyat2tmfxn33xb4t7waafgmsa... --- kernel/bpf/verifier.c | 48 +++++++++++++++++++++++++++++------------------- 1 file changed, 29 insertions(+), 19 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 856cb77d0f87..2b1e24c440c5 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -9339,11 +9339,13 @@ static void clear_caller_saved_regs(struct bpf_verifier_env *env, typedef int (*set_callee_state_fn)(struct bpf_verifier_env *env, struct bpf_func_state *caller, struct bpf_func_state *callee, - int insn_idx); + int insn_idx, + struct bpf_kfunc_call_arg_meta *meta);
static int set_callee_state(struct bpf_verifier_env *env, struct bpf_func_state *caller, - struct bpf_func_state *callee, int insn_idx); + struct bpf_func_state *callee, int insn_idx, + struct bpf_kfunc_call_arg_meta *meta);
static int setup_func_entry(struct bpf_verifier_env *env, int subprog, int callsite, set_callee_state_fn set_callee_state_cb, @@ -9381,7 +9383,7 @@ static int setup_func_entry(struct bpf_verifier_env *env, int subprog, int calls subprog /* subprog number within this prog */); /* Transfer references to the callee */ err = copy_reference_state(callee, caller); - err = err ?: set_callee_state_cb(env, caller, callee, callsite); + err = err ?: set_callee_state_cb(env, caller, callee, callsite, NULL); if (err) goto err_out;
@@ -9518,7 +9520,8 @@ static int btf_check_subprog_call(struct bpf_verifier_env *env, int subprog,
static int push_callback_call(struct bpf_verifier_env *env, struct bpf_insn *insn, int insn_idx, int subprog, - set_callee_state_fn set_callee_state_cb) + set_callee_state_fn set_callee_state_cb, + struct bpf_kfunc_call_arg_meta *kfunc_meta) { struct bpf_verifier_state *state = env->cur_state, *callback_state; struct bpf_func_state *caller, *callee; @@ -9560,7 +9563,7 @@ static int push_callback_call(struct bpf_verifier_env *env, struct bpf_insn *ins callee->async_entry_cnt = caller->async_entry_cnt + 1;
/* Convert bpf_timer_set_callback() args into timer callback args */ - err = set_callee_state_cb(env, caller, callee, insn_idx); + err = set_callee_state_cb(env, caller, callee, insn_idx, kfunc_meta); if (err) return err;
@@ -9691,7 +9694,8 @@ int map_set_for_each_callback_args(struct bpf_verifier_env *env,
static int set_callee_state(struct bpf_verifier_env *env, struct bpf_func_state *caller, - struct bpf_func_state *callee, int insn_idx) + struct bpf_func_state *callee, int insn_idx, + struct bpf_kfunc_call_arg_meta *meta) { int i;
@@ -9706,7 +9710,8 @@ static int set_callee_state(struct bpf_verifier_env *env, static int set_map_elem_callback_state(struct bpf_verifier_env *env, struct bpf_func_state *caller, struct bpf_func_state *callee, - int insn_idx) + int insn_idx, + struct bpf_kfunc_call_arg_meta *meta) { struct bpf_insn_aux_data *insn_aux = &env->insn_aux_data[insn_idx]; struct bpf_map *map; @@ -9732,7 +9737,8 @@ static int set_map_elem_callback_state(struct bpf_verifier_env *env, static int set_loop_callback_state(struct bpf_verifier_env *env, struct bpf_func_state *caller, struct bpf_func_state *callee, - int insn_idx) + int insn_idx, + struct bpf_kfunc_call_arg_meta *meta) { /* bpf_loop(u32 nr_loops, void *callback_fn, void *callback_ctx, * u64 flags); @@ -9754,7 +9760,8 @@ static int set_loop_callback_state(struct bpf_verifier_env *env, static int set_timer_callback_state(struct bpf_verifier_env *env, struct bpf_func_state *caller, struct bpf_func_state *callee, - int insn_idx) + int insn_idx, + struct bpf_kfunc_call_arg_meta *meta) { struct bpf_map *map_ptr = caller->regs[BPF_REG_1].map_ptr;
@@ -9784,7 +9791,8 @@ static int set_timer_callback_state(struct bpf_verifier_env *env, static int set_find_vma_callback_state(struct bpf_verifier_env *env, struct bpf_func_state *caller, struct bpf_func_state *callee, - int insn_idx) + int insn_idx, + struct bpf_kfunc_call_arg_meta *meta) { /* bpf_find_vma(struct task_struct *task, u64 addr, * void *callback_fn, void *callback_ctx, u64 flags) @@ -9812,7 +9820,8 @@ static int set_find_vma_callback_state(struct bpf_verifier_env *env, static int set_user_ringbuf_callback_state(struct bpf_verifier_env *env, struct bpf_func_state *caller, struct bpf_func_state *callee, - int insn_idx) + int insn_idx, + struct bpf_kfunc_call_arg_meta *meta) { /* bpf_user_ringbuf_drain(struct bpf_map *map, void *callback_fn, void * callback_ctx, u64 flags); @@ -9835,7 +9844,8 @@ static int set_user_ringbuf_callback_state(struct bpf_verifier_env *env, static int set_rbtree_add_callback_state(struct bpf_verifier_env *env, struct bpf_func_state *caller, struct bpf_func_state *callee, - int insn_idx) + int insn_idx, + struct bpf_kfunc_call_arg_meta *meta) { /* void bpf_rbtree_add_impl(struct bpf_rb_root *root, struct bpf_rb_node *node, * bool (less)(struct bpf_rb_node *a, const struct bpf_rb_node *b)); @@ -10411,15 +10421,15 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn break; case BPF_FUNC_for_each_map_elem: err = push_callback_call(env, insn, insn_idx, meta.subprogno, - set_map_elem_callback_state); + set_map_elem_callback_state, NULL); break; case BPF_FUNC_timer_set_callback: err = push_callback_call(env, insn, insn_idx, meta.subprogno, - set_timer_callback_state); + set_timer_callback_state, NULL); break; case BPF_FUNC_find_vma: err = push_callback_call(env, insn, insn_idx, meta.subprogno, - set_find_vma_callback_state); + set_find_vma_callback_state, NULL); break; case BPF_FUNC_snprintf: err = check_bpf_snprintf_call(env, regs); @@ -10434,7 +10444,7 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn return err; if (cur_func(env)->callback_depth < regs[BPF_REG_1].umax_value) { err = push_callback_call(env, insn, insn_idx, meta.subprogno, - set_loop_callback_state); + set_loop_callback_state, NULL); } else { cur_func(env)->callback_depth = 0; if (env->log.level & BPF_LOG_LEVEL2) @@ -10537,7 +10547,7 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn } case BPF_FUNC_user_ringbuf_drain: err = push_callback_call(env, insn, insn_idx, meta.subprogno, - set_user_ringbuf_callback_state); + set_user_ringbuf_callback_state, NULL); break; }
@@ -12285,7 +12295,7 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
if (meta.func_id == special_kfunc_list[KF_bpf_rbtree_add_impl]) { err = push_callback_call(env, insn, insn_idx, meta.subprogno, - set_rbtree_add_callback_state); + set_rbtree_add_callback_state, &meta); if (err) { verbose(env, "kfunc %s#%d failed callback verification\n", func_name, meta.func_id); @@ -12295,7 +12305,7 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
if (is_bpf_wq_set_callback_impl_kfunc(meta.func_id)) { err = push_callback_call(env, insn, insn_idx, meta.subprogno, - set_timer_callback_state); + set_timer_callback_state, &meta); if (err) { verbose(env, "kfunc %s#%d failed callback verification\n", func_name, meta.func_id);