1  /*
  2   *
  3   * Copyright (c) 2012 Google Inc.
  4   *
  5   * Redistribution and use in source and binary forms, with or without
  6   * modification, are permitted provided that the following conditions
  7   * are met:
  8   * 1. Redistributions of source code must retain the above copyright
  9   *    notice, this list of conditions and the following disclaimer.
 10   * 2. Redistributions in binary form must reproduce the above copyright
 11   *    notice, this list of conditions and the following disclaimer in the
 12   *    documentation and/or other materials provided with the distribution.
 13   * 3. The name of the author may not be used to endorse or promote products
 14   *    derived from this software without specific prior written permission.
 15   *
 16   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 17   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 18   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 19   * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 20   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 21   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 22   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 23   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 24   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 25   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 26   * SUCH DAMAGE.
 27   */
 28  
 29  #include <libpayload.h>
 30  #include <stdint.h>
 31  
 32  struct cbmem_console {
 33  	uint32_t size;
 34  	uint32_t cursor;
 35  	uint8_t body[];
 36  } __packed;
 37  
 38  #define CURSOR_MASK ((1 << 28) - 1)
 39  #define OVERFLOW (1 << 31)
 40  
 41  static uintptr_t cbmem_console_p;
 42  
 43  static struct console_output_driver cbmem_console_driver =
 44  {
 45  	.write = &cbmem_console_write,
 46  };
 47  
 48  static void do_write(const void *buffer, size_t count)
 49  {
 50  	struct cbmem_console *const cbmem_cons = phys_to_virt(cbmem_console_p);
 51  
 52  	memcpy(cbmem_cons->body + (cbmem_cons->cursor & CURSOR_MASK), buffer, count);
 53  	cbmem_cons->cursor += count;
 54  }
 55  
 56  void cbmem_console_init(void)
 57  {
 58  	const struct cbmem_console *const cbmem_cons = phys_to_virt(lib_sysinfo.cbmem_cons);
 59  
 60  	cbmem_console_p = lib_sysinfo.cbmem_cons;
 61  
 62  	if (cbmem_console_p && cbmem_cons->size)
 63  		console_add_output_driver(&cbmem_console_driver);
 64  }
 65  
 66  void cbmem_console_write(const void *buffer, size_t count)
 67  {
 68  	struct cbmem_console *const cbmem_cons = phys_to_virt(cbmem_console_p);
 69  
 70  	while ((cbmem_cons->cursor & CURSOR_MASK) + count >=
 71  	       cbmem_cons->size) {
 72  		size_t still_fits = cbmem_cons->size - (cbmem_cons->cursor & CURSOR_MASK);
 73  		do_write(buffer, still_fits);
 74  		cbmem_cons->cursor &= ~CURSOR_MASK;
 75  		cbmem_cons->cursor |= OVERFLOW;
 76  		buffer += still_fits;
 77  		count -= still_fits;
 78  	}
 79  
 80  	do_write(buffer, count);
 81  }
 82  
 83  static void snapshot_putc(char *console, uint32_t *cursor, char c)
 84  {
 85  	/* This is BIOS_LOG_IS_MARKER() from coreboot. Due to stupid
 86  	   licensing restrictions, we can't use it directly. */
 87  	if (c >= 0x10 && c <= 0x18)
 88  		return;
 89  
 90  	/* Slight memory corruption may occur between reboots and give us a few
 91  	   unprintable characters like '\0'. Replace them with '?' on output. */
 92  	if (!isprint(c) && !isspace(c))
 93  		console[*cursor] = '?';
 94  	else
 95  		console[*cursor] = c;
 96  
 97  	*cursor += 1;
 98  }
 99  
100  char *cbmem_console_snapshot(void)
101  {
102  	const struct cbmem_console *const console_p = phys_to_virt(cbmem_console_p);
103  	char *console_c;
104  	uint32_t size, cursor, overflow, newc, oldc;
105  
106  	if (!console_p) {
107  		printf("ERROR: No cbmem console found in coreboot table\n");
108  		return NULL;
109  	}
110  
111  	cursor = console_p->cursor & CURSOR_MASK;
112  	overflow = console_p->cursor & OVERFLOW;
113  	if (!overflow && cursor < console_p->size)
114  		size = cursor;
115  	else
116  		size = console_p->size;
117  
118  	console_c = malloc(size + 1);
119  	if (!console_c) {
120  		printf("ERROR: Not enough memory for console (size = %u)\n",
121  		       size);
122  		return NULL;
123  	}
124  
125  	newc = 0;
126  	if (overflow) {
127  		if (cursor >= size) {
128  			printf("ERROR: CBMEM console struct is corrupted\n");
129  			return NULL;
130  		}
131  		for (oldc = cursor; oldc < size; oldc++)
132  			snapshot_putc(console_c, &newc, console_p->body[oldc]);
133  	}
134  	for (oldc = 0; oldc < size && oldc < cursor; oldc++)
135  		snapshot_putc(console_c, &newc, console_p->body[oldc]);
136  	console_c[newc] = '\0';
137  
138  	return console_c;
139  }