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Diffstat (limited to 'arch/x86/boot/tools/build.c')
-rw-r--r--arch/x86/boot/tools/build.c168
1 files changed, 168 insertions, 0 deletions
diff --git a/arch/x86/boot/tools/build.c b/arch/x86/boot/tools/build.c
new file mode 100644
index 000000000000..b4248740ff0d
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+++ b/arch/x86/boot/tools/build.c
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+/*
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ * Copyright (C) 1997 Martin Mares
+ * Copyright (C) 2007 H. Peter Anvin
+ */
+
+/*
+ * This file builds a disk-image from two different files:
+ *
+ * - setup: 8086 machine code, sets up system parm
+ * - system: 80386 code for actual system
+ *
+ * It does some checking that all files are of the correct type, and
+ * just writes the result to stdout, removing headers and padding to
+ * the right amount. It also writes some system data to stderr.
+ */
+
+/*
+ * Changes by tytso to allow root device specification
+ * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996
+ * Cross compiling fixes by Gertjan van Wingerde, July 1996
+ * Rewritten by Martin Mares, April 1997
+ * Substantially overhauled by H. Peter Anvin, April 2007
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/sysmacros.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <asm/boot.h>
+
+typedef unsigned char u8;
+typedef unsigned short u16;
+typedef unsigned long u32;
+
+#define DEFAULT_MAJOR_ROOT 0
+#define DEFAULT_MINOR_ROOT 0
+
+/* Minimal number of setup sectors */
+#define SETUP_SECT_MIN 5
+#define SETUP_SECT_MAX 64
+
+/* This must be large enough to hold the entire setup */
+u8 buf[SETUP_SECT_MAX*512];
+int is_big_kernel;
+
+static void die(const char * str, ...)
+{
+ va_list args;
+ va_start(args, str);
+ vfprintf(stderr, str, args);
+ fputc('\n', stderr);
+ exit(1);
+}
+
+static void usage(void)
+{
+ die("Usage: build [-b] setup system [rootdev] [> image]");
+}
+
+int main(int argc, char ** argv)
+{
+ unsigned int i, sz, setup_sectors;
+ int c;
+ u32 sys_size;
+ u8 major_root, minor_root;
+ struct stat sb;
+ FILE *file;
+ int fd;
+ void *kernel;
+
+ if (argc > 2 && !strcmp(argv[1], "-b"))
+ {
+ is_big_kernel = 1;
+ argc--, argv++;
+ }
+ if ((argc < 3) || (argc > 4))
+ usage();
+ if (argc > 3) {
+ if (!strcmp(argv[3], "CURRENT")) {
+ if (stat("/", &sb)) {
+ perror("/");
+ die("Couldn't stat /");
+ }
+ major_root = major(sb.st_dev);
+ minor_root = minor(sb.st_dev);
+ } else if (strcmp(argv[3], "FLOPPY")) {
+ if (stat(argv[3], &sb)) {
+ perror(argv[3]);
+ die("Couldn't stat root device.");
+ }
+ major_root = major(sb.st_rdev);
+ minor_root = minor(sb.st_rdev);
+ } else {
+ major_root = 0;
+ minor_root = 0;
+ }
+ } else {
+ major_root = DEFAULT_MAJOR_ROOT;
+ minor_root = DEFAULT_MINOR_ROOT;
+ }
+ fprintf(stderr, "Root device is (%d, %d)\n", major_root, minor_root);
+
+ /* Copy the setup code */
+ file = fopen(argv[1], "r");
+ if (!file)
+ die("Unable to open `%s': %m", argv[1]);
+ c = fread(buf, 1, sizeof(buf), file);
+ if (ferror(file))
+ die("read-error on `setup'");
+ if (c < 1024)
+ die("The setup must be at least 1024 bytes");
+ if (buf[510] != 0x55 || buf[511] != 0xaa)
+ die("Boot block hasn't got boot flag (0xAA55)");
+ fclose(file);
+
+ /* Pad unused space with zeros */
+ setup_sectors = (c + 511) / 512;
+ if (setup_sectors < SETUP_SECT_MIN)
+ setup_sectors = SETUP_SECT_MIN;
+ i = setup_sectors*512;
+ memset(buf+c, 0, i-c);
+
+ /* Set the default root device */
+ buf[508] = minor_root;
+ buf[509] = major_root;
+
+ fprintf(stderr, "Setup is %d bytes (padded to %d bytes).\n", c, i);
+
+ /* Open and stat the kernel file */
+ fd = open(argv[2], O_RDONLY);
+ if (fd < 0)
+ die("Unable to open `%s': %m", argv[2]);
+ if (fstat(fd, &sb))
+ die("Unable to stat `%s': %m", argv[2]);
+ sz = sb.st_size;
+ fprintf (stderr, "System is %d kB\n", (sz+1023)/1024);
+ kernel = mmap(NULL, sz, PROT_READ, MAP_SHARED, fd, 0);
+ if (kernel == MAP_FAILED)
+ die("Unable to mmap '%s': %m", argv[2]);
+ sys_size = (sz + 15) / 16;
+ if (!is_big_kernel && sys_size > DEF_SYSSIZE)
+ die("System is too big. Try using bzImage or modules.");
+
+ /* Patch the setup code with the appropriate size parameters */
+ buf[0x1f1] = setup_sectors-1;
+ buf[0x1f4] = sys_size;
+ buf[0x1f5] = sys_size >> 8;
+ buf[0x1f6] = sys_size >> 16;
+ buf[0x1f7] = sys_size >> 24;
+
+ if (fwrite(buf, 1, i, stdout) != i)
+ die("Writing setup failed");
+
+ /* Copy the kernel code */
+ if (fwrite(kernel, 1, sz, stdout) != sz)
+ die("Writing kernel failed");
+ close(fd);
+
+ /* Everything is OK */
+ return 0;
+}