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 */
43void (*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 */
49unsigned int disable_serial_output = FALSE;
50#else
51unsigned int disable_serial_output = TRUE;
52#endif
53
54decl_simple_lock_data(static, kprintf_lock)
55
56void 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
90static 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
103static int cpu_last_locked = 0;
104void 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
149extern void kprintf_break_lock(void);
150void
151kprintf_break_lock(void)
152{
153	simple_lock_init(&kprintf_lock, 0);
154}
155