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 #include <machine/pal_routines.h>
  39
  40 /* Globals */
  41 void (*PE_kputc)(char c);
  42
  43 #if DEBUG
  44 /* DEBUG kernel starts with true serial, but
  45  * may later disable or switch to video
  46  * console */
  47 unsigned int disable_serial_output = FALSE;
  48 #else
  49 unsigned int disable_serial_output = TRUE;
  50 #endif
  51
  52 decl_simple_lock_data(static, kprintf_lock)
  53
  54 void PE_init_kprintf(boolean_t vm_initialized)
  55 {
  56         unsigned int    boot_arg;
  57
  58         if (PE_state.initialized == FALSE)
  59                 panic("Platform Expert not initialized");
  60
  61         if (!vm_initialized) {
  62                 unsigned int new_disable_serial_output = TRUE;
  63
  64                 simple_lock_init(&kprintf_lock, 0);
  65
  66                 if (PE_parse_boot_argn("debug", &boot_arg, sizeof (boot_arg)))
  67                         if (boot_arg & DB_KPRT)
  68                                 new_disable_serial_output = FALSE;
  69
  70                 /* If we are newly enabling serial, make sure we only
  71                  * call pal_serial_init() if our previous state was
  72                  * not enabled */
  73                 if (!new_disable_serial_output && (!disable_serial_output || pal_serial_init()))
  74                         PE_kputc = pal_serial_putc;
  75                 else
  76                         PE_kputc = cnputc;
  77
  78                 disable_serial_output = new_disable_serial_output;
  79         }
  80 }
  81
  82 #if CONFIG_NO_KPRINTF_STRINGS
  83 /* Prevent CPP from breaking the definition below */
  84 #undef kprintf
  85 #endif
  86
  87 #ifdef MP_DEBUG
  88 static void _kprintf(const char *format, ...)
  89 {
  90         va_list   listp;
  91
  92         va_start(listp, format);
  93         _doprnt(format, &listp, PE_kputc, 16);
  94         va_end(listp);
  95 }
  96 #define MP_DEBUG_KPRINTF(x...)  _kprintf(x)
  97 #else  /* MP_DEBUG */
  98 #define MP_DEBUG_KPRINTF(x...)
  99 #endif /* MP_DEBUG */
 100
 101 static int cpu_last_locked = 0;
 102 void kprintf(const char *fmt, ...)
 103 {
 104         va_list   listp;
 105         boolean_t state;
 106
 107         if (!disable_serial_output) {
 108
 109                 /* If PE_kputc has not yet been initialized, don't
 110                  * take any locks, just dump to serial */
 111                 if (!PE_kputc) {
 112                         va_start(listp, fmt);
 113                         _doprnt(fmt, &listp, pal_serial_putc, 16);
 114                         va_end(listp);
 115                         return;
 116                 }
 117
 118                 /*
 119                  * Spin to get kprintf lock but re-enable interrupts while
 120                  * failing.
 121                  * This allows interrupts to be handled while waiting but
 122                  * interrupts are disabled once we have the lock.
 123                  */
 124                 state = ml_set_interrupts_enabled(FALSE);
 125
 126                 pal_preemption_assert();
 127
 128                 while (!simple_lock_try(&kprintf_lock)) {
 129                         ml_set_interrupts_enabled(state);
 130                         ml_set_interrupts_enabled(FALSE);
 131                 }
 132
 133                 if (cpu_number() != cpu_last_locked) {
 134                         MP_DEBUG_KPRINTF("[cpu%d...]\n", cpu_number());
 135                         cpu_last_locked = cpu_number();
 136                 }
 137
 138                 va_start(listp, fmt);
 139                 _doprnt(fmt, &listp, PE_kputc, 16);
 140                 va_end(listp);
 141
 142                 simple_unlock(&kprintf_lock);
 143                 ml_set_interrupts_enabled(state);
 144         }
 145 }
 146
 147 extern void kprintf_break_lock(void);
 148 void
 149 kprintf_break_lock(void)
 150 {
 151         simple_lock_init(&kprintf_lock, 0);
 152 }