pexpert/i386/pe_kprintf.c

   1 /*
   2  * Copyright (c) 2000-2019 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*
  29  * file: pe_kprintf.c
  30  *    i386 platform expert debugging output initialization.
  31  */
  32 #include <stdarg.h>
  33 #include <machine/machine_routines.h>
  34 #include <pexpert/pexpert.h>
  35 #include <kern/debug.h>
  36 #include <kern/simple_lock.h>
  37 #include <i386/machine_cpu.h>
  38 #include <i386/mp.h>
  39 #include <machine/pal_routines.h>
  40 #include <i386/proc_reg.h>
  41 #include <os/log_private.h>
  42 #include <libkern/section_keywords.h>
  43 #include <kern/processor.h>
  44 #include <kern/clock.h>
  45 #include <mach/clock_types.h>
  46
  47 extern uint64_t LockTimeOut;
  48
  49 /* Globals */
  50 typedef void (*PE_kputc_t)(char);
  51
  52 #if XNU_TARGET_OS_OSX
  53 PE_kputc_t PE_kputc;
  54 #else
  55 SECURITY_READ_ONLY_LATE(PE_kputc_t) PE_kputc;
  56 #endif
  57
  58 #if DEVELOPMENT || DEBUG
  59 /* DEBUG kernel starts with true serial, but
  60  * may later disable or switch to video
  61  * console */
  62 SECURITY_READ_ONLY_LATE(unsigned int) disable_serial_output = FALSE;
  63 #else
  64 SECURITY_READ_ONLY_LATE(unsigned int) disable_serial_output = TRUE;
  65 #endif
  66
  67 static SIMPLE_LOCK_DECLARE(kprintf_lock, 0);
  68
  69 __startup_func
  70 static void
  71 PE_init_kprintf(void)
  72 {
  73         if (PE_state.initialized == FALSE) {
  74                 panic("Platform Expert not initialized");
  75         }
  76
  77         unsigned int new_disable_serial_output = TRUE;
  78
  79         if (debug_boot_arg & DB_KPRT) {
  80                 new_disable_serial_output = FALSE;
  81         }
  82
  83         /* If we are newly enabling serial, make sure we only
  84          * call pal_serial_init() if our previous state was
  85          * not enabled */
  86         if (!new_disable_serial_output && (!disable_serial_output || pal_serial_init())) {
  87                 PE_kputc = pal_serial_putc;
  88         } else {
  89                 PE_kputc = cnputc_unbuffered;
  90         }
  91
  92         disable_serial_output = new_disable_serial_output;
  93 }
  94 STARTUP(KPRINTF, STARTUP_RANK_FIRST, PE_init_kprintf);
  95
  96 #if CONFIG_NO_KPRINTF_STRINGS
  97 /* Prevent CPP from breaking the definition below */
  98 #undef kprintf
  99 #endif
 100
 101 #ifdef MP_DEBUG
 102 static void
 103 _kprintf(const char *format, ...)
 104 {
 105         va_list   listp;
 106
 107         va_start(listp, format);
 108         _doprnt(format, &listp, PE_kputc, 16);
 109         va_end(listp);
 110 }
 111 #define MP_DEBUG_KPRINTF(x...)  _kprintf(x)
 112 #else  /* MP_DEBUG */
 113 #define MP_DEBUG_KPRINTF(x...)
 114 #endif /* MP_DEBUG */
 115
 116 static int cpu_last_locked = 0;
 117
 118 #define KPRINTF_LOCKWAIT_PATIENT (LockTimeOut)
 119 #define KPRINTF_LOCKWAIT_IMPATIENT (LockTimeOut >> 4)
 120
 121 __attribute__((noinline, not_tail_called))
 122 void
 123 kprintf(const char *fmt, ...)
 124 {
 125         va_list    listp;
 126         va_list    listp2;
 127         boolean_t  state;
 128         boolean_t  in_panic_context = FALSE;
 129         unsigned int kprintf_lock_grabbed;
 130         void      *caller = __builtin_return_address(0);
 131
 132         if (!disable_serial_output) {
 133                 boolean_t early = FALSE;
 134                 uint64_t gsbase = rdmsr64(MSR_IA32_GS_BASE);
 135                 if (gsbase == EARLY_GSBASE_MAGIC || gsbase == 0) {
 136                         early = TRUE;
 137                 }
 138                 /* If PE_kputc has not yet been initialized, don't
 139                  * take any locks, just dump to serial */
 140                 if (!PE_kputc || early) {
 141                         va_start(listp, fmt);
 142                         va_copy(listp2, listp);
 143
 144                         _doprnt_log(fmt, &listp, pal_serial_putc, 16);
 145                         va_end(listp);
 146
 147                         // If interrupts are enabled
 148                         if (ml_get_interrupts_enabled()) {
 149                                 os_log_with_args(OS_LOG_DEFAULT, OS_LOG_TYPE_DEFAULT, fmt, listp2, caller);
 150                         }
 151                         va_end(listp2);
 152                         return;
 153                 }
 154
 155                 va_start(listp, fmt);
 156                 va_copy(listp2, listp);
 157
 158                 state = ml_set_interrupts_enabled(FALSE);
 159
 160                 pal_preemption_assert();
 161
 162                 in_panic_context = debug_is_current_cpu_in_panic_state();
 163
 164                 // If current CPU is in panic context, be a little more impatient.
 165                 kprintf_lock_grabbed = simple_lock_try_lock_mp_signal_safe_loop_duration(&kprintf_lock,
 166                     in_panic_context ? KPRINTF_LOCKWAIT_IMPATIENT : KPRINTF_LOCKWAIT_PATIENT,
 167                     LCK_GRP_NULL);
 168
 169                 if (cpu_number() != cpu_last_locked) {
 170                         MP_DEBUG_KPRINTF("[cpu%d...]\n", cpu_number());
 171                         cpu_last_locked = cpu_number();
 172                 }
 173
 174                 _doprnt(fmt, &listp, PE_kputc, 16);
 175
 176                 if (kprintf_lock_grabbed) {
 177                         simple_unlock(&kprintf_lock);
 178                 }
 179
 180                 ml_set_interrupts_enabled(state);
 181
 182                 va_end(listp);
 183
 184                 // If interrupts are enabled
 185                 if (ml_get_interrupts_enabled()) {
 186                         os_log_with_args(OS_LOG_DEFAULT, OS_LOG_TYPE_DEFAULT, fmt, listp2, caller);
 187                 }
 188                 va_end(listp2);
 189         } else {
 190                 if (ml_get_interrupts_enabled()) {
 191                         va_start(listp, fmt);
 192                         os_log_with_args(OS_LOG_DEFAULT, OS_LOG_TYPE_DEFAULT, fmt, listp, caller);
 193                         va_end(listp);
 194                 }
 195         }
 196 }
 197
 198 extern void kprintf_break_lock(void);
 199 void
 200 kprintf_break_lock(void)
 201 {
 202         simple_lock_init(&kprintf_lock, 0);
 203 }