Linux Kernel  3.7.1
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main.c
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1 /*
2  * Copyright (C) Paul Mackerras 1997.
3  *
4  * Updates for PPC64 by Todd Inglett, Dave Engebretsen & Peter Bergner.
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License
8  * as published by the Free Software Foundation; either version
9  * 2 of the License, or (at your option) any later version.
10  */
11 #include <stdarg.h>
12 #include <stddef.h>
13 #include "elf.h"
14 #include "page.h"
15 #include "string.h"
16 #include "stdio.h"
17 #include "ops.h"
18 #include "gunzip_util.h"
19 #include "reg.h"
20 
21 static struct gunzip_state gzstate;
22 
23 struct addr_range {
24  void *addr;
25  unsigned long size;
26 };
27 
28 #undef DEBUG
29 
30 static struct addr_range prep_kernel(void)
31 {
32  char elfheader[256];
33  void *vmlinuz_addr = _vmlinux_start;
34  unsigned long vmlinuz_size = _vmlinux_end - _vmlinux_start;
35  void *addr = 0;
36  struct elf_info ei;
37  int len;
38 
39  /* gunzip the ELF header of the kernel */
40  gunzip_start(&gzstate, vmlinuz_addr, vmlinuz_size);
41  gunzip_exactly(&gzstate, elfheader, sizeof(elfheader));
42 
43  if (!parse_elf64(elfheader, &ei) && !parse_elf32(elfheader, &ei))
44  fatal("Error: not a valid PPC32 or PPC64 ELF file!\n\r");
45 
47  platform_ops.image_hdr(elfheader);
48 
49  /* We need to alloc the memsize: gzip will expand the kernel
50  * text/data, then possible rubbish we don't care about. But
51  * the kernel bss must be claimed (it will be zero'd by the
52  * kernel itself)
53  */
54  printf("Allocating 0x%lx bytes for kernel ...\n\r", ei.memsize);
55 
58  } else {
59  /*
60  * Check if the kernel image (without bss) would overwrite the
61  * bootwrapper. The device tree has been moved in fdt_init()
62  * to an area allocated with malloc() (somewhere past _end).
63  */
64  if ((unsigned long)_start < ei.loadsize)
65  fatal("Insufficient memory for kernel at address 0!"
66  " (_start=%p, uncompressed size=%08lx)\n\r",
67  _start, ei.loadsize);
68 
69  if ((unsigned long)_end < ei.memsize)
70  fatal("The final kernel image would overwrite the "
71  "device tree\n\r");
72  }
73 
74  /* Finally, gunzip the kernel */
75  printf("gunzipping (0x%p <- 0x%p:0x%p)...", addr,
76  vmlinuz_addr, vmlinuz_addr+vmlinuz_size);
77  /* discard up to the actual load data */
78  gunzip_discard(&gzstate, ei.elfoffset - sizeof(elfheader));
79  len = gunzip_finish(&gzstate, addr, ei.loadsize);
80  if (len != ei.loadsize)
81  fatal("ran out of data! only got 0x%x of 0x%lx bytes.\n\r",
82  len, ei.loadsize);
83  printf("done 0x%x bytes\n\r", len);
84 
86 
87  return (struct addr_range){addr, ei.memsize};
88 }
89 
90 static struct addr_range prep_initrd(struct addr_range vmlinux, void *chosen,
91  unsigned long initrd_addr,
92  unsigned long initrd_size)
93 {
94  /* If we have an image attached to us, it overrides anything
95  * supplied by the loader. */
96  if (_initrd_end > _initrd_start) {
97  printf("Attached initrd image at 0x%p-0x%p\n\r",
98  _initrd_start, _initrd_end);
99  initrd_addr = (unsigned long)_initrd_start;
100  initrd_size = _initrd_end - _initrd_start;
101  } else if (initrd_size > 0) {
102  printf("Using loader supplied ramdisk at 0x%lx-0x%lx\n\r",
103  initrd_addr, initrd_addr + initrd_size);
104  }
105 
106  /* If there's no initrd at all, we're done */
107  if (! initrd_size)
108  return (struct addr_range){0, 0};
109 
110  /*
111  * If the initrd is too low it will be clobbered when the
112  * kernel relocates to its final location. In this case,
113  * allocate a safer place and move it.
114  */
115  if (initrd_addr < vmlinux.size) {
116  void *old_addr = (void *)initrd_addr;
117 
118  printf("Allocating 0x%lx bytes for initrd ...\n\r",
119  initrd_size);
120  initrd_addr = (unsigned long)malloc(initrd_size);
121  if (! initrd_addr)
122  fatal("Can't allocate memory for initial "
123  "ramdisk !\n\r");
124  printf("Relocating initrd 0x%lx <- 0x%p (0x%lx bytes)\n\r",
125  initrd_addr, old_addr, initrd_size);
126  memmove((void *)initrd_addr, old_addr, initrd_size);
127  }
128 
129  printf("initrd head: 0x%lx\n\r", *((unsigned long *)initrd_addr));
130 
131  /* Tell the kernel initrd address via device tree */
132  setprop_val(chosen, "linux,initrd-start", (u32)(initrd_addr));
133  setprop_val(chosen, "linux,initrd-end", (u32)(initrd_addr+initrd_size));
134 
135  return (struct addr_range){(void *)initrd_addr, initrd_size};
136 }
137 
138 /* A buffer that may be edited by tools operating on a zImage binary so as to
139  * edit the command line passed to vmlinux (by setting /chosen/bootargs).
140  * The buffer is put in it's own section so that tools may locate it easier.
141  */
142 static char cmdline[COMMAND_LINE_SIZE]
143  __attribute__((__section__("__builtin_cmdline")));
144 
145 static void prep_cmdline(void *chosen)
146 {
147  if (cmdline[0] == '\0')
148  getprop(chosen, "bootargs", cmdline, COMMAND_LINE_SIZE-1);
149 
150  printf("\n\rLinux/PowerPC load: %s", cmdline);
151  /* If possible, edit the command line */
154  printf("\n\r");
155 
156  /* Put the command line back into the devtree for the kernel */
157  setprop_str(chosen, "bootargs", cmdline);
158 }
159 
161 struct dt_ops dt_ops;
164 
165 void start(void)
166 {
167  struct addr_range vmlinux, initrd;
168  kernel_entry_t kentry;
169  unsigned long ft_addr = 0;
170  void *chosen;
171 
172  /* Do this first, because malloc() could clobber the loader's
173  * command line. Only use the loader command line if a
174  * built-in command line wasn't set by an external tool */
175  if ((loader_info.cmdline_len > 0) && (cmdline[0] == '\0'))
178 
179  if (console_ops.open && (console_ops.open() < 0))
180  exit();
181  if (platform_ops.fixups)
183 
184  printf("\n\rzImage starting: loaded at 0x%p (sp: 0x%p)\n\r",
185  _start, get_sp());
186 
187  /* Ensure that the device tree has a /chosen node */
188  chosen = finddevice("/chosen");
189  if (!chosen)
190  chosen = create_node(NULL, "chosen");
191 
192  vmlinux = prep_kernel();
193  initrd = prep_initrd(vmlinux, chosen,
195  prep_cmdline(chosen);
196 
197  printf("Finalizing device tree...");
198  if (dt_ops.finalize)
199  ft_addr = dt_ops.finalize();
200  if (ft_addr)
201  printf(" flat tree at 0x%lx\n\r", ft_addr);
202  else
203  printf(" using OF tree (promptr=%p)\n\r", loader_info.promptr);
204 
205  if (console_ops.close)
206  console_ops.close();
207 
208  kentry = (kernel_entry_t) vmlinux.addr;
209  if (ft_addr)
210  kentry(ft_addr, 0, NULL);
211  else
212  kentry((unsigned long)initrd.addr, initrd.size,
214 
215  /* console closed so printf in fatal below may not work */
216  fatal("Error: Linux kernel returned to zImage boot wrapper!\n\r");
217 }