xnu-792.6.56.tar.gz

[apple/xnu.git] / pexpert / i386 / pe_kprintf.c

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this
 * file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*
 * file: pe_kprintf.c
 *    i386 platform expert debugging output initialization.
 */
#include <stdarg.h>
#include <machine/machine_routines.h>
#include <pexpert/pexpert.h>
#include <kern/debug.h>
#include <kern/simple_lock.h>
#include <i386/mp.h>

/* extern references */
extern void cnputc(char c);
extern int  serial_init(void);
extern void serial_putc(char c);

/* Globals */
void (*PE_kputc)(char c) = 0;

unsigned int disableSerialOuput = TRUE;

decl_simple_lock_data(static, kprintf_lock)

void PE_init_kprintf(boolean_t vm_initialized)
{
	unsigned int	boot_arg;

	if (PE_state.initialized == FALSE)
		panic("Platform Expert not initialized");

	if (!vm_initialized)
	{
        simple_lock_init(&kprintf_lock, 0);

	    if (PE_parse_boot_arg("debug", &boot_arg)) 
	        if (boot_arg & DB_KPRT) disableSerialOuput = FALSE;

        if (!disableSerialOuput && serial_init())
            PE_kputc = serial_putc;
        else
            PE_kputc = cnputc;
    }
}

#ifdef MP_DEBUG
static void _kprintf(const char *format, ...)
{
	va_list   listp;

        va_start(listp, format);
        _doprnt(format, &listp, PE_kputc, 16);
        va_end(listp);
}
#define MP_DEBUG_KPRINTF(x...)	_kprintf(x)
#else  /* MP_DEBUG */
#define MP_DEBUG_KPRINTF(x...)
#endif /* MP_DEBUG */

static int cpu_last_locked = 0;
void kprintf(const char *fmt, ...)
{
	va_list   listp;
    boolean_t state;
    
    if (!disableSerialOuput) {

	/*
	 * Spin to get kprintf lock but re-enable interrupts while failing.
	 * This allows interrupts to be handled while waiting but
	 * interrupts are disabled once we have the lock.
	 */
	state = ml_set_interrupts_enabled(FALSE);
	while (!simple_lock_try(&kprintf_lock)) {
             ml_set_interrupts_enabled(state);
             ml_set_interrupts_enabled(FALSE);
	}

	if (cpu_number() != cpu_last_locked) {
	    MP_DEBUG_KPRINTF("[cpu%d...]\n", cpu_number());
	    cpu_last_locked = cpu_number();
	}

        va_start(listp, fmt);
        _doprnt(fmt, &listp, PE_kputc, 16);
        va_end(listp);

        simple_unlock(&kprintf_lock);
        ml_set_interrupts_enabled(state);
    }
}