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 #include <i386/proc_reg.h>
  40
  41 /* Globals */
  42 void (*PE_kputc)(char c);
  43
  44 #if DEBUG
  45 /* DEBUG kernel starts with true serial, but
  46  * may later disable or switch to video
  47  * console */
  48 unsigned int disable_serial_output = FALSE;
  49 #else
  50 unsigned int disable_serial_output = TRUE;
  51 #endif
  52
  53 decl_simple_lock_data(static, kprintf_lock)
  54
  55 void PE_init_kprintf(boolean_t vm_initialized)
  56 {
  57         unsigned int    boot_arg;
  58
  59         if (PE_state.initialized == FALSE)
  60                 panic("Platform Expert not initialized");
  61
  62         if (!vm_initialized) {
  63                 unsigned int new_disable_serial_output = TRUE;
  64
  65                 simple_lock_init(&kprintf_lock, 0);
  66
  67                 if (PE_parse_boot_argn("debug", &boot_arg, sizeof (boot_arg)))
  68                         if (boot_arg & DB_KPRT)
  69                                 new_disable_serial_output = FALSE;
  70
  71                 /* If we are newly enabling serial, make sure we only
  72                  * call pal_serial_init() if our previous state was
  73                  * not enabled */
  74                 if (!new_disable_serial_output && (!disable_serial_output || pal_serial_init()))
  75                         PE_kputc = pal_serial_putc;
  76                 else
  77                         PE_kputc = cnputc;
  78
  79                 disable_serial_output = new_disable_serial_output;
  80         }
  81 }
  82
  83 #if CONFIG_NO_KPRINTF_STRINGS
  84 /* Prevent CPP from breaking the definition below */
  85 #undef kprintf
  86 #endif
  87
  88 #ifdef MP_DEBUG
  89 static void _kprintf(const char *format, ...)
  90 {
  91         va_list   listp;
  92
  93         va_start(listp, format);
  94         _doprnt(format, &listp, PE_kputc, 16);
  95         va_end(listp);
  96 }
  97 #define MP_DEBUG_KPRINTF(x...)  _kprintf(x)
  98 #else  /* MP_DEBUG */
  99 #define MP_DEBUG_KPRINTF(x...)
 100 #endif /* MP_DEBUG */
 101
 102 static int cpu_last_locked = 0;
 103 void kprintf(const char *fmt, ...)
 104 {
 105         va_list   listp;
 106         boolean_t state;
 107
 108         if (!disable_serial_output) {
 109                 boolean_t early = FALSE;
 110                 if (rdmsr64(MSR_IA32_GS_BASE) == 0) {
 111                         early = TRUE;
 112                 }
 113                 /* If PE_kputc has not yet been initialized, don't
 114                  * take any locks, just dump to serial */
 115                 if (!PE_kputc || early) {
 116                         va_start(listp, fmt);
 117                         _doprnt(fmt, &listp, pal_serial_putc, 16);
 118                         va_end(listp);
 119                         return;
 120                 }
 121
 122                 /*
 123                  * Spin to get kprintf lock but re-enable interrupts while
 124                  * failing.
 125                  * This allows interrupts to be handled while waiting but
 126                  * interrupts are disabled once we have the lock.
 127                  */
 128                 state = ml_set_interrupts_enabled(FALSE);
 129
 130                 pal_preemption_assert();
 131
 132                 while (!simple_lock_try(&kprintf_lock)) {
 133                         ml_set_interrupts_enabled(state);
 134                         ml_set_interrupts_enabled(FALSE);
 135                 }
 136
 137                 if (cpu_number() != cpu_last_locked) {
 138                         MP_DEBUG_KPRINTF("[cpu%d...]\n", cpu_number());
 139                         cpu_last_locked = cpu_number();
 140                 }
 141
 142                 va_start(listp, fmt);
 143                 _doprnt(fmt, &listp, PE_kputc, 16);
 144                 va_end(listp);
 145
 146                 simple_unlock(&kprintf_lock);
 147                 ml_set_interrupts_enabled(state);
 148         }
 149 }
 150
 151 extern void kprintf_break_lock(void);
 152 void
 153 kprintf_break_lock(void)
 154 {
 155         simple_lock_init(&kprintf_lock, 0);
 156 }