1/* 2 * Copyright 2010 Tilera Corporation. All Rights Reserved. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation, version 2. 7 * 8 * This program is distributed in the hope that it will be useful, but 9 * WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or 11 * NON INFRINGEMENT. See the GNU General Public License for 12 * more details. 13 */ 14 15#include <linux/console.h> 16#include <linux/kernel.h> 17#include <linux/init.h> 18#include <linux/string.h> 19#include <asm/setup.h> 20#include <hv/hypervisor.h> 21 22static void early_hv_write(struct console *con, const char *s, unsigned n) 23{ 24 hv_console_write((HV_VirtAddr) s, n); 25} 26 27static struct console early_hv_console = { 28 .name = "earlyhv", 29 .write = early_hv_write, 30 .flags = CON_PRINTBUFFER, 31 .index = -1, 32}; 33 34/* Direct interface for emergencies */ 35static struct console *early_console = &early_hv_console; 36static int early_console_initialized; 37static int early_console_complete; 38 39static void early_vprintk(const char *fmt, va_list ap) 40{ 41 char buf[512]; 42 int n = vscnprintf(buf, sizeof(buf), fmt, ap); 43 early_console->write(early_console, buf, n); 44} 45 46void early_printk(const char *fmt, ...) 47{ 48 va_list ap; 49 va_start(ap, fmt); 50 early_vprintk(fmt, ap); 51 va_end(ap); 52} 53 54void early_panic(const char *fmt, ...) 55{ 56 va_list ap; 57 raw_local_irq_disable_all(); 58 va_start(ap, fmt); 59 early_printk("Kernel panic - not syncing: "); 60 early_vprintk(fmt, ap); 61 early_console->write(early_console, "\n", 1); 62 va_end(ap); 63 dump_stack(); 64 hv_halt(); 65} 66 67static int __initdata keep_early; 68 69static int __init setup_early_printk(char *str) 70{ 71 if (early_console_initialized) 72 return 1; 73 74 if (str != NULL && strncmp(str, "keep", 4) == 0) 75 keep_early = 1; 76 77 early_console = &early_hv_console; 78 early_console_initialized = 1; 79 register_console(early_console); 80 81 return 0; 82} 83 84void __init disable_early_printk(void) 85{ 86 early_console_complete = 1; 87 if (!early_console_initialized || !early_console) 88 return; 89 if (!keep_early) { 90 early_printk("disabling early console\n"); 91 unregister_console(early_console); 92 early_console_initialized = 0; 93 } else { 94 early_printk("keeping early console\n"); 95 } 96} 97 98void warn_early_printk(void) 99{ 100 if (early_console_complete || early_console_initialized) 101 return; 102 early_printk("\ 103Machine shutting down before console output is fully initialized.\n\ 104You may wish to reboot and add the option 'earlyprintk' to your\n\ 105boot command line to see any diagnostic early console output.\n\ 106"); 107} 108 109early_param("earlyprintk", setup_early_printk); 110