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 */
17 typedef void (*PE_kputc_t)(char);
18 SECURITY_READ_ONLY_LATE(PE_kputc_t) PE_kputc;
19
20 // disable_serial_output disables kprintf() *and* unbuffered panic output.
21 SECURITY_READ_ONLY_LATE(bool) disable_serial_output = true;
22 // disable_kprintf_output only disables kprintf().
23 SECURITY_READ_ONLY_LATE(bool) disable_kprintf_output = true;
24 // disable_iolog_serial_output only disables IOLog, controlled by
25 // SERIALMODE_NO_IOLOG.
26 SECURITY_READ_ONLY_LATE(bool) disable_iolog_serial_output = false;
27 SECURITY_READ_ONLY_LATE(bool) enable_dklog_serial_output = false;
28
29 static SIMPLE_LOCK_DECLARE(kprintf_lock, 0);
30
31 static void serial_putc_crlf(char c);
32
33 __startup_func
34 static void
PE_init_kprintf_config(void)35 PE_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.
55 STARTUP(TUNABLES, STARTUP_RANK_LAST, PE_init_kprintf_config);
56
57 __startup_func
58 static void
PE_init_kprintf(void)59 PE_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 }
72 STARTUP(KPRINTF, STARTUP_RANK_FIRST, PE_init_kprintf);
73
74 #ifdef MP_DEBUG
75 static void
_kprintf(const char * format,...)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
94 static int cpu_last_locked = 0;
95
96 __attribute__((noinline, not_tail_called))
97 void
kprintf(const char * fmt,...)98 kprintf(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(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, &listp, PE_kputc, 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(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, OS_LOG_TYPE_DEFAULT, fmt, listp2, caller);
147 va_end(listp2);
148 } else {
149 va_start(listp, fmt);
150 os_log_with_args(OS_LOG_DEFAULT, OS_LOG_TYPE_DEFAULT, fmt, listp, caller);
151 va_end(listp);
152 }
153 #pragma clang diagnostic pop
154 }
155
156 static void
serial_putc_crlf(char c)157 serial_putc_crlf(char c)
158 {
159 if (c == '\n') {
160 uart_putc('\r');
161 }
162 uart_putc(c);
163 }
164
165 void
serial_putc_options(char c,bool poll)166 serial_putc_options(char c, bool poll)
167 {
168 uart_putc_options(c, poll);
169 }
170
171 void
serial_putc(char c)172 serial_putc(char c)
173 {
174 uart_putc(c);
175 }
176
177 int
serial_getc(void)178 serial_getc(void)
179 {
180 return uart_getc();
181 }
182