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 */
42void (*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 */
48unsigned int disable_serial_output = FALSE;
49#else
50unsigned int disable_serial_output = TRUE;
51#endif
52
53decl_simple_lock_data(static, kprintf_lock)
54
55void 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
89static 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
102static int cpu_last_locked = 0;
103void 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
151extern void kprintf_break_lock(void);
152void
153kprintf_break_lock(void)
154{
155	simple_lock_init(&kprintf_lock, 0);
156}
157