arch/x86/boot/compressed/mkpiggy.c

   1 /* ----------------------------------------------------------------------- *
   2  *
   3  *  Copyright (C) 2009 Intel Corporation. All rights reserved.
   4  *
   5  *  This program is free software; you can redistribute it and/or
   6  *  modify it under the terms of the GNU General Public License version
   7  *  2 as published by the Free Software Foundation.
   8  *
   9  *  This program is distributed in the hope that it will be useful,
  10  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  *  GNU General Public License for more details.
  13  *
  14  *  You should have received a copy of the GNU General Public License
  15  *  along with this program; if not, write to the Free Software
  16  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  17  *  02110-1301, USA.
  18  *
  19  *  H. Peter Anvin <hpa@linux.intel.com>
  20  *
  21  * ----------------------------------------------------------------------- */
  22
  23 /*
  24  * Compute the desired load offset from a compressed program; outputs
  25  * a small assembly wrapper with the appropriate symbols defined.
  26  */
  27
  28 #include <stdlib.h>
  29 #include <stdio.h>
  30 #include <string.h>
  31 #include <inttypes.h>
  32
  33 static uint32_t getle32(const void *p)
  34 {
  35         const uint8_t *cp = p;
  36
  37         return (uint32_t)cp[0] + ((uint32_t)cp[1] << 8) +
  38                 ((uint32_t)cp[2] << 16) + ((uint32_t)cp[3] << 24);
  39 }
  40
  41 int main(int argc, char *argv[])
  42 {
  43         uint32_t olen;
  44         long ilen;
  45         unsigned long offs;
  46         FILE *f;
  47
  48         if (argc < 2) {
  49                 fprintf(stderr, "Usage: %s compressed_file\n", argv[0]);
  50                 return 1;
  51         }
  52
  53         /* Get the information for the compressed kernel image first */
  54
  55         f = fopen(argv[1], "r");
  56         if (!f) {
  57                 perror(argv[1]);
  58                 return 1;
  59         }
  60
  61
  62         if (fseek(f, -4L, SEEK_END)) {
  63                 perror(argv[1]);
  64         }
  65         fread(&olen, sizeof olen, 1, f);
  66         ilen = ftell(f);
  67         olen = getle32(&olen);
  68         fclose(f);
  69
  70         /*
  71          * Now we have the input (compressed) and output (uncompressed)
  72          * sizes, compute the necessary decompression offset...
  73          */
  74
  75         offs = (olen > ilen) ? olen - ilen : 0;
  76         offs += olen >> 12;     /* Add 8 bytes for each 32K block */
  77         offs += 32*1024 + 18;   /* Add 32K + 18 bytes slack */
  78         offs = (offs+4095) & ~4095; /* Round to a 4K boundary */
  79
  80         printf(".section \".rodata..compressed\",\"a\",@progbits\n");
  81         printf(".globl z_input_len\n");
  82         printf("z_input_len = %lu\n", ilen);
  83         printf(".globl z_output_len\n");
  84         printf("z_output_len = %lu\n", (unsigned long)olen);
  85         printf(".globl z_extract_offset\n");
  86         printf("z_extract_offset = 0x%lx\n", offs);
  87         /* z_extract_offset_negative allows simplification of head_32.S */
  88         printf(".globl z_extract_offset_negative\n");
  89         printf("z_extract_offset_negative = -0x%lx\n", offs);
  90
  91         printf(".globl input_data, input_data_end\n");
  92         printf("input_data:\n");
  93         printf(".incbin \"%s\"\n", argv[1]);
  94         printf("input_data_end:\n");
  95
  96         return 0;
  97 }