payloads/libpayload/drivers/cbmem_console.c

   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[0];
  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 }