pexpert/arm/pe_kprintf.c

   1 /*
   2  * Copyright (c) 2000-2007 Apple Inc. All rights reserved.
   3  */
   4 /*
   5  * file: pe_kprintf.c
   6  *    arm platform expert debugging output initialization.
   7  */
   8 #include <stdarg.h>
   9 #include <machine/machine_routines.h>
  10 #include <pexpert/pexpert.h>
  11 #include <kern/debug.h>
  12 #include <kern/simple_lock.h>
  13 #include <os/log_private.h>
  14 #include <libkern/section_keywords.h>
  15
  16 /* Globals */
  17 void            (*PE_kputc) (char c) = 0;
  18
  19 SECURITY_READ_ONLY_LATE(unsigned int)    disable_serial_output = TRUE;
  20
  21 decl_simple_lock_data(static, kprintf_lock)
  22
  23 void
  24 PE_init_kprintf(boolean_t vm_initialized)
  25 {
  26         unsigned int    boot_arg;
  27
  28         if (PE_state.initialized == FALSE)
  29                 panic("Platform Expert not initialized");
  30
  31         if (!vm_initialized) {
  32                 simple_lock_init(&kprintf_lock, 0);
  33
  34                 if (PE_parse_boot_argn("debug", &boot_arg, sizeof (boot_arg)))
  35                         if (boot_arg & DB_KPRT)
  36                                 disable_serial_output = FALSE;
  37
  38                 if (serial_init())
  39                         PE_kputc = serial_putc;
  40                 else
  41                         PE_kputc = cnputc;
  42         }
  43 }
  44
  45 #ifdef MP_DEBUG
  46 static void
  47 _kprintf(const char *format,...)
  48 {
  49         va_list         listp;
  50
  51         va_start(listp, format);
  52         _doprnt_log(format, &listp, PE_kputc, 16);
  53         va_end(listp);
  54 }
  55 #define MP_DEBUG_KPRINTF(x...)  _kprintf(x)
  56 #else                           /* MP_DEBUG */
  57 #define MP_DEBUG_KPRINTF(x...)
  58 #endif                          /* MP_DEBUG */
  59
  60 #if CONFIG_NO_KPRINTF_STRINGS
  61 /* Prevent CPP from breaking the definition below */
  62 #undef kprintf
  63 #endif
  64
  65 static int      cpu_last_locked = 0;
  66
  67 __attribute__((noinline,not_tail_called))
  68 void kprintf(const char *fmt,...)
  69 {
  70         va_list         listp;
  71         va_list         listp2;
  72         boolean_t       state;
  73         void           *caller = __builtin_return_address(0);
  74
  75         if (!disable_serial_output) {
  76
  77                 /*
  78                  * Spin to get kprintf lock but re-enable interrupts while failing.
  79                  * This allows interrupts to be handled while waiting but
  80                  * interrupts are disabled once we have the lock.
  81                  */
  82                 state = ml_set_interrupts_enabled(FALSE);
  83                 while (!simple_lock_try(&kprintf_lock)) {
  84                         ml_set_interrupts_enabled(state);
  85                         ml_set_interrupts_enabled(FALSE);
  86                 }
  87
  88                 if (cpu_number() != cpu_last_locked) {
  89                         MP_DEBUG_KPRINTF("[cpu%d...]\n", cpu_number());
  90                         cpu_last_locked = cpu_number();
  91                 }
  92
  93                 va_start(listp, fmt);
  94                 va_copy(listp2, listp);
  95                 _doprnt_log(fmt, &listp, PE_kputc, 16);
  96                 va_end(listp);
  97
  98                 simple_unlock(&kprintf_lock);
  99
 100 #if INTERRUPT_MASKED_DEBUG
 101                 /*
 102                  * kprintf holds interrupts disabled for far too long
 103                  * and would trip the spin-debugger.  If we are about to reenable
 104                  * interrupts then clear the timer and avoid panicking on the delay.
 105                  * Otherwise, let the code that printed with interrupt disabled
 106                  * take the panic when it reenables interrupts.
 107                  * Hopefully one day this is fixed so that this workaround is unnecessary.
 108                  */
 109                 if (state == TRUE)
 110                         ml_spin_debug_clear_self();
 111 #endif
 112                 ml_set_interrupts_enabled(state);
 113
 114                 // If interrupts are enabled
 115                 if (ml_get_interrupts_enabled()) {
 116                         os_log_with_args(OS_LOG_DEFAULT, OS_LOG_TYPE_DEFAULT, fmt, listp2, caller);
 117                 }
 118                 va_end(listp2);
 119         }
 120         else {
 121                 // If interrupts are enabled
 122                 if (ml_get_interrupts_enabled()) {
 123                         va_start(listp, fmt);
 124                         os_log_with_args(OS_LOG_DEFAULT, OS_LOG_TYPE_DEFAULT, fmt, listp, caller);
 125                         va_end(listp);
 126                 }
 127         }
 128 }
 129
 130 void
 131 serial_putc(char c)
 132 {
 133         uart_putc(c);
 134 }
 135
 136 int
 137 serial_getc(void)
 138 {
 139         return uart_getc();
 140 }
 141