1/*
2 * Copyright (c) 2000-2019 Apple Inc. All rights reserved.
3 */
4/*
5 * file: pe_kprintf.c
6 * arm platform expert debugging output initialization.
7 */
8#include <stdarg.h>
9#include <machine/machine_routines.h>
10#include <pexpert/pexpert.h>
11#include <kern/debug.h>
12#include <kern/simple_lock.h>
13#include <os/log_private.h>
14#include <libkern/section_keywords.h>
15
16/* Globals */
17typedef void (*PE_kputc_t)(char);
18SECURITY_READ_ONLY_LATE(PE_kputc_t) PE_kputc;
19
20// disable_serial_output disables kprintf() *and* unbuffered panic output.
21SECURITY_READ_ONLY_LATE(bool) disable_serial_output = true;
22// disable_kprintf_output only disables kprintf().
23SECURITY_READ_ONLY_LATE(bool) disable_kprintf_output = true;
24// disable_iolog_serial_output only disables IOLog, controlled by
25// SERIALMODE_NO_IOLOG.
26SECURITY_READ_ONLY_LATE(bool) disable_iolog_serial_output = false;
27SECURITY_READ_ONLY_LATE(bool) enable_dklog_serial_output = false;
28
29static SIMPLE_LOCK_DECLARE(kprintf_lock, 0);
30
31static void serial_putc_crlf(char c);
32
33__startup_func
34static void
35PE_init_kprintf_config(void)
36{
37 if (PE_state.initialized == FALSE) {
38 panic("Platform Expert not initialized");
39 }
40
41 if (debug_boot_arg & DB_KPRT) {
42 disable_serial_output = false;
43 }
44
45#if DEBUG
46 disable_kprintf_output = false;
47#elif DEVELOPMENT
48 bool enable_kprintf_spam = false;
49 if (PE_parse_boot_argn("-enable_kprintf_spam", &enable_kprintf_spam, sizeof(enable_kprintf_spam))) {
50 disable_kprintf_output = false;
51 }
52#endif
53}
54// Do this early, so other code can depend on whether kprintf is enabled.
55STARTUP(TUNABLES, STARTUP_RANK_LAST, PE_init_kprintf_config);
56
57__startup_func
58static void
59PE_init_kprintf(void)
60{
61 if (serial_init()) {
62 PE_kputc = serial_putc_crlf;
63 } else {
64 /**
65 * If serial failed to initialize then fall back to using the console,
66 * and assume the console is using the video console (because clearly
67 * serial doesn't work).
68 */
69 PE_kputc = console_write_unbuffered;
70 }
71}
72STARTUP(KPRINTF, STARTUP_RANK_FIRST, PE_init_kprintf);
73
74#ifdef MP_DEBUG
75static void
76_kprintf(const char *format, ...)
77{
78 va_list listp;
79
80 va_start(listp, format);
81 _doprnt_log(format, &listp, PE_kputc, 16);
82 va_end(listp);
83}
84#define MP_DEBUG_KPRINTF(x...) _kprintf(x)
85#else /* MP_DEBUG */
86#define MP_DEBUG_KPRINTF(x...)
87#endif /* MP_DEBUG */
88
89#if CONFIG_NO_KPRINTF_STRINGS
90/* Prevent CPP from breaking the definition below */
91#undef kprintf
92#endif
93
94static int cpu_last_locked = 0;
95
96__attribute__((noinline, not_tail_called))
97void
98kprintf(const char *fmt, ...)
99{
100 va_list listp;
101 va_list listp2;
102 boolean_t state;
103 void *caller = __builtin_return_address(0);
104
105 if (!disable_serial_output && !disable_kprintf_output) {
106 va_start(listp, fmt);
107 va_copy(listp2, listp);
108 /*
109 * Spin to get kprintf lock but re-enable interrupts while failing.
110 * This allows interrupts to be handled while waiting but
111 * interrupts are disabled once we have the lock.
112 */
113 state = ml_set_interrupts_enabled(FALSE);
114 while (!simple_lock_try(&kprintf_lock, LCK_GRP_NULL)) {
115 ml_set_interrupts_enabled(enable: state);
116 ml_set_interrupts_enabled(FALSE);
117 }
118
119 if (cpu_number() != cpu_last_locked) {
120 MP_DEBUG_KPRINTF("[cpu%d...]\n", cpu_number());
121 cpu_last_locked = cpu_number();
122 }
123
124 _doprnt_log(fmt, argp: &listp, putc: PE_kputc, radix: 16);
125
126 simple_unlock(&kprintf_lock);
127
128#if SCHED_HYGIENE_DEBUG
129 /*
130 * kprintf holds interrupts disabled for far too long
131 * and would trip the spin-debugger. If we are about to reenable
132 * interrupts then clear the timer and avoid panicking on the delay.
133 * Otherwise, let the code that printed with interrupt disabled
134 * take the panic when it reenables interrupts.
135 * Hopefully one day this is fixed so that this workaround is unnecessary.
136 */
137 if (state == TRUE) {
138 ml_spin_debug_clear_self();
139 }
140#endif
141 ml_set_interrupts_enabled(enable: state);
142 va_end(listp);
143
144#pragma clang diagnostic push
145#pragma clang diagnostic ignored "-Wformat-nonliteral"
146 os_log_with_args(OS_LOG_DEFAULT, type: OS_LOG_TYPE_DEFAULT, format: fmt, args: listp2, ret_addr: caller);
147 va_end(listp2);
148 } else {
149 va_start(listp, fmt);
150 os_log_with_args(OS_LOG_DEFAULT, type: OS_LOG_TYPE_DEFAULT, format: fmt, args: listp, ret_addr: caller);
151 va_end(listp);
152 }
153#pragma clang diagnostic pop
154}
155
156static void
157serial_putc_crlf(char c)
158{
159 if (c == '\n') {
160 uart_putc('\r');
161 }
162 uart_putc(c);
163}
164
165void
166serial_putc_options(char c, bool poll)
167{
168 uart_putc_options(c, poll);
169}
170
171void
172serial_putc(char c)
173{
174 uart_putc(c);
175}
176
177int
178serial_getc(void)
179{
180 return uart_getc();
181}
182