pexpert/i386/pe_kprintf.c

   1 /*
   2  * Copyright (c) 2000-2006 Apple Computer, 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/mp.h>
  38
  39 /* Globals */
  40 void (*PE_kputc)(char c);
  41
  42 #if DEBUG
  43 /* DEBUG kernel starts with true serial, but
  44  * may later disable or switch to video
  45  * console */
  46 unsigned int disable_serial_output = FALSE;
  47 #else
  48 unsigned int disable_serial_output = TRUE;
  49 #endif
  50
  51 decl_simple_lock_data(static, kprintf_lock)
  52
  53 void PE_init_kprintf(boolean_t vm_initialized)
  54 {
  55         unsigned int    boot_arg;
  56
  57         if (PE_state.initialized == FALSE)
  58                 panic("Platform Expert not initialized");
  59
  60         if (!vm_initialized) {
  61                 unsigned int new_disable_serial_output = TRUE;
  62
  63                 simple_lock_init(&kprintf_lock, 0);
  64
  65                 if (PE_parse_boot_argn("debug", &boot_arg, sizeof (boot_arg)))
  66                         if (boot_arg & DB_KPRT)
  67                                 new_disable_serial_output = FALSE;
  68
  69                 /* If we are newly enabling serial, make sure we only call serial_init()
  70                  * if our previous state was not enabled */
  71                 if (!new_disable_serial_output && (!disable_serial_output || serial_init()))
  72                         PE_kputc = serial_putc;
  73                 else
  74                         PE_kputc = cnputc;
  75
  76                 disable_serial_output = new_disable_serial_output;
  77         }
  78 }
  79
  80 #if CONFIG_NO_KPRINTF_STRINGS
  81 /* Prevent CPP from breaking the definition below */
  82 #undef kprintf
  83 #endif
  84
  85 #ifdef MP_DEBUG
  86 static void _kprintf(const char *format, ...)
  87 {
  88         va_list   listp;
  89
  90         va_start(listp, format);
  91         _doprnt(format, &listp, PE_kputc, 16);
  92         va_end(listp);
  93 }
  94 #define MP_DEBUG_KPRINTF(x...)  _kprintf(x)
  95 #else  /* MP_DEBUG */
  96 #define MP_DEBUG_KPRINTF(x...)
  97 #endif /* MP_DEBUG */
  98
  99 static int cpu_last_locked = 0;
 100 void kprintf(const char *fmt, ...)
 101 {
 102         va_list   listp;
 103         boolean_t state;
 104
 105         if (!disable_serial_output) {
 106
 107                 /* If PE_kputc has not yet been initialized, don't
 108                  * take any locks, just dump to serial */
 109                 if (!PE_kputc) {
 110                         va_start(listp, fmt);
 111                         _doprnt(fmt, &listp, serial_putc, 16);
 112                         va_end(listp);
 113                         return;
 114                 }
 115
 116                 /*
 117                  * Spin to get kprintf lock but re-enable interrupts while
 118                  * failing.
 119                  * This allows interrupts to be handled while waiting but
 120                  * interrupts are disabled once we have the lock.
 121                  */
 122                 state = ml_set_interrupts_enabled(FALSE);
 123                 while (!simple_lock_try(&kprintf_lock)) {
 124                         ml_set_interrupts_enabled(state);
 125                         ml_set_interrupts_enabled(FALSE);
 126                 }
 127
 128                 if (cpu_number() != cpu_last_locked) {
 129                         MP_DEBUG_KPRINTF("[cpu%d...]\n", cpu_number());
 130                         cpu_last_locked = cpu_number();
 131                 }
 132
 133                 va_start(listp, fmt);
 134                 _doprnt(fmt, &listp, PE_kputc, 16);
 135                 va_end(listp);
 136
 137                 simple_unlock(&kprintf_lock);
 138                 ml_set_interrupts_enabled(state);
 139         }
 140 }
 141
 142 extern void kprintf_break_lock(void);
 143 void
 144 kprintf_break_lock(void)
 145 {
 146         simple_lock_init(&kprintf_lock, 0);
 147 }