1// Copyright 2016 The Fuchsia Authors
2// Copyright (c) 2013 Travis Geiselbrecht
3//
4// Use of this source code is governed by a MIT-style
5// license that can be found in the LICENSE file or at
6// https://opensource.org/licenses/MIT
7
8/*
9 * Global init hook mechanism. Allows code anywhere in the system to define
10 * a init hook that is called at increasing init levels as the system is
11 * initialized.
12 */
13#include <arch/ops.h>
14#include <lk/init.h>
15
16#include <assert.h>
17#include <debug.h>
18#include <trace.h>
19#include <zircon/compiler.h>
20
21#define LOCAL_TRACE 0
22#define TRACE_INIT (LK_DEBUGLEVEL >= 2)
23#ifndef EARLIEST_TRACE_LEVEL
24#define EARLIEST_TRACE_LEVEL LK_INIT_LEVEL_TARGET_EARLY
25#endif
26
27extern const struct lk_init_struct __start_lk_init[];
28extern const struct lk_init_struct __stop_lk_init[];
29
30void lk_init_level(enum lk_init_flags required_flag, uint start_level, uint stop_level) {
31    LTRACEF("flags %#x, start_level %#x, stop_level %#x\n",
32            (uint)required_flag, start_level, stop_level);
33
34    ASSERT(start_level > 0);
35    uint last_called_level = start_level - 1;
36    const struct lk_init_struct* last = NULL;
37    for (;;) {
38        /* search for the lowest uncalled hook to call */
39        LTRACEF("last %p, last_called_level %#x\n", last, last_called_level);
40
41        const struct lk_init_struct* found = NULL;
42        bool seen_last = false;
43        for (const struct lk_init_struct* ptr = __start_lk_init; ptr != __stop_lk_init; ptr++) {
44            LTRACEF("looking at %p (%s) level %#x, flags %#x, seen_last %d\n", ptr, ptr->name, ptr->level, ptr->flags, seen_last);
45
46            if (ptr == last)
47                seen_last = true;
48
49            /* reject the easy ones */
50            if (!(ptr->flags & required_flag))
51                continue;
52            if (ptr->level > stop_level)
53                continue;
54            if (ptr->level < last_called_level)
55                continue;
56            if (found && found->level <= ptr->level)
57                continue;
58
59            /* keep the lowest one we haven't called yet */
60            if (ptr->level >= start_level && ptr->level > last_called_level) {
61                found = ptr;
62                continue;
63            }
64
65            /* if we're at the same level as the last one we called and we've
66             * already passed over it this time around, we can mark this one
67             * and early terminate the loop.
68             */
69            if (ptr->level == last_called_level && ptr != last && seen_last) {
70                found = ptr;
71                break;
72            }
73        }
74
75        if (!found)
76            break;
77
78        if (TRACE_INIT) {
79            if (found->level >= EARLIEST_TRACE_LEVEL) {
80                printf("INIT: cpu %u, calling hook %p (%s) at level %#x, flags %#x\n",
81                       arch_curr_cpu_num(), found->hook, found->name, found->level, found->flags);
82            }
83        }
84
85        found->hook(found->level);
86        last_called_level = found->level;
87        last = found;
88    }
89}
90