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