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v3.1
  1/*
  2 * misc.c
  3 *
  4 * This is a collection of several routines from gzip-1.0.3
  5 * adapted for Linux.
 
 
  6 *
  7 * malloc by Hannu Savolainen 1993 and Matthias Urlichs 1994
  8 * puts by Nick Holloway 1993, better puts by Martin Mares 1995
  9 * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996
 10 */
 11
 12#include "misc.h"
 13
 14/* WARNING!!
 15 * This code is compiled with -fPIC and it is relocated dynamically
 16 * at run time, but no relocation processing is performed.
 17 * This means that it is not safe to place pointers in static structures.
 18 */
 19
 20/*
 21 * Getting to provable safe in place decompression is hard.
 22 * Worst case behaviours need to be analyzed.
 23 * Background information:
 24 *
 25 * The file layout is:
 26 *    magic[2]
 27 *    method[1]
 28 *    flags[1]
 29 *    timestamp[4]
 30 *    extraflags[1]
 31 *    os[1]
 32 *    compressed data blocks[N]
 33 *    crc[4] orig_len[4]
 34 *
 35 * resulting in 18 bytes of non compressed data overhead.
 36 *
 37 * Files divided into blocks
 38 * 1 bit (last block flag)
 39 * 2 bits (block type)
 40 *
 41 * 1 block occurs every 32K -1 bytes or when there 50% compression
 42 * has been achieved. The smallest block type encoding is always used.
 43 *
 44 * stored:
 45 *    32 bits length in bytes.
 46 *
 47 * fixed:
 48 *    magic fixed tree.
 49 *    symbols.
 50 *
 51 * dynamic:
 52 *    dynamic tree encoding.
 53 *    symbols.
 54 *
 55 *
 56 * The buffer for decompression in place is the length of the
 57 * uncompressed data, plus a small amount extra to keep the algorithm safe.
 58 * The compressed data is placed at the end of the buffer.  The output
 59 * pointer is placed at the start of the buffer and the input pointer
 60 * is placed where the compressed data starts.  Problems will occur
 61 * when the output pointer overruns the input pointer.
 62 *
 63 * The output pointer can only overrun the input pointer if the input
 64 * pointer is moving faster than the output pointer.  A condition only
 65 * triggered by data whose compressed form is larger than the uncompressed
 66 * form.
 67 *
 68 * The worst case at the block level is a growth of the compressed data
 69 * of 5 bytes per 32767 bytes.
 70 *
 71 * The worst case internal to a compressed block is very hard to figure.
 72 * The worst case can at least be boundined by having one bit that represents
 73 * 32764 bytes and then all of the rest of the bytes representing the very
 74 * very last byte.
 75 *
 76 * All of which is enough to compute an amount of extra data that is required
 77 * to be safe.  To avoid problems at the block level allocating 5 extra bytes
 78 * per 32767 bytes of data is sufficient.  To avoind problems internal to a
 79 * block adding an extra 32767 bytes (the worst case uncompressed block size)
 80 * is sufficient, to ensure that in the worst case the decompressed data for
 81 * block will stop the byte before the compressed data for a block begins.
 82 * To avoid problems with the compressed data's meta information an extra 18
 83 * bytes are needed.  Leading to the formula:
 84 *
 85 * extra_bytes = (uncompressed_size >> 12) + 32768 + 18 + decompressor_size.
 86 *
 87 * Adding 8 bytes per 32K is a bit excessive but much easier to calculate.
 88 * Adding 32768 instead of 32767 just makes for round numbers.
 89 * Adding the decompressor_size is necessary as it musht live after all
 90 * of the data as well.  Last I measured the decompressor is about 14K.
 91 * 10K of actual data and 4K of bss.
 92 *
 93 */
 94
 95/*
 96 * gzip declarations
 97 */
 98#define STATIC		static
 99
100#undef memset
 
 
 
 
101#undef memcpy
 
102#define memzero(s, n)	memset((s), 0, (n))
 
103
104
105static void error(char *m);
106
107/*
108 * This is set up by the setup-routine at boot-time
109 */
110struct boot_params *real_mode;		/* Pointer to real-mode data */
111static int quiet;
112static int debug;
113
114void *memset(void *s, int c, size_t n);
115void *memcpy(void *dest, const void *src, size_t n);
116
117#ifdef CONFIG_X86_64
118#define memptr long
119#else
120#define memptr unsigned
121#endif
122
123static memptr free_mem_ptr;
124static memptr free_mem_end_ptr;
125
126static char *vidmem;
127static int vidport;
128static int lines, cols;
129
130#ifdef CONFIG_KERNEL_GZIP
131#include "../../../../lib/decompress_inflate.c"
132#endif
133
134#ifdef CONFIG_KERNEL_BZIP2
135#include "../../../../lib/decompress_bunzip2.c"
136#endif
137
138#ifdef CONFIG_KERNEL_LZMA
139#include "../../../../lib/decompress_unlzma.c"
140#endif
141
142#ifdef CONFIG_KERNEL_XZ
143#include "../../../../lib/decompress_unxz.c"
144#endif
145
146#ifdef CONFIG_KERNEL_LZO
147#include "../../../../lib/decompress_unlzo.c"
148#endif
149
 
 
 
 
 
 
 
 
150static void scroll(void)
151{
152	int i;
153
154	memcpy(vidmem, vidmem + cols * 2, (lines - 1) * cols * 2);
155	for (i = (lines - 1) * cols * 2; i < lines * cols * 2; i += 2)
156		vidmem[i] = ' ';
157}
158
159#define XMTRDY          0x20
160
161#define TXR             0       /*  Transmit register (WRITE) */
162#define LSR             5       /*  Line Status               */
163static void serial_putchar(int ch)
164{
165	unsigned timeout = 0xffff;
166
167	while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
168		cpu_relax();
169
170	outb(ch, early_serial_base + TXR);
171}
172
173void __putstr(int error, const char *s)
174{
175	int x, y, pos;
176	char c;
177
178#ifndef CONFIG_X86_VERBOSE_BOOTUP
179	if (!error)
180		return;
181#endif
182	if (early_serial_base) {
183		const char *str = s;
184		while (*str) {
185			if (*str == '\n')
186				serial_putchar('\r');
187			serial_putchar(*str++);
188		}
189	}
190
191	if (real_mode->screen_info.orig_video_mode == 0 &&
192	    lines == 0 && cols == 0)
193		return;
194
195	x = real_mode->screen_info.orig_x;
196	y = real_mode->screen_info.orig_y;
197
198	while ((c = *s++) != '\0') {
199		if (c == '\n') {
200			x = 0;
201			if (++y >= lines) {
202				scroll();
203				y--;
204			}
205		} else {
206			vidmem[(x + cols * y) * 2] = c;
207			if (++x >= cols) {
208				x = 0;
209				if (++y >= lines) {
210					scroll();
211					y--;
212				}
213			}
214		}
215	}
216
217	real_mode->screen_info.orig_x = x;
218	real_mode->screen_info.orig_y = y;
219
220	pos = (x + cols * y) * 2;	/* Update cursor position */
221	outb(14, vidport);
222	outb(0xff & (pos >> 9), vidport+1);
223	outb(15, vidport);
224	outb(0xff & (pos >> 1), vidport+1);
225}
226
227void *memset(void *s, int c, size_t n)
228{
229	int i;
230	char *ss = s;
231
232	for (i = 0; i < n; i++)
233		ss[i] = c;
234	return s;
235}
236#ifdef CONFIG_X86_32
237void *memcpy(void *dest, const void *src, size_t n)
238{
239	int d0, d1, d2;
240	asm volatile(
241		"rep ; movsl\n\t"
242		"movl %4,%%ecx\n\t"
243		"rep ; movsb\n\t"
244		: "=&c" (d0), "=&D" (d1), "=&S" (d2)
245		: "0" (n >> 2), "g" (n & 3), "1" (dest), "2" (src)
246		: "memory");
247
248	return dest;
249}
250#else
251void *memcpy(void *dest, const void *src, size_t n)
252{
253	long d0, d1, d2;
254	asm volatile(
255		"rep ; movsq\n\t"
256		"movq %4,%%rcx\n\t"
257		"rep ; movsb\n\t"
258		: "=&c" (d0), "=&D" (d1), "=&S" (d2)
259		: "0" (n >> 3), "g" (n & 7), "1" (dest), "2" (src)
260		: "memory");
261
262	return dest;
 
263}
264#endif
265
266static void error(char *x)
 
 
267{
268	__putstr(1, "\n\n");
269	__putstr(1, x);
270	__putstr(1, "\n\n -- System halted");
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
271
272	while (1)
273		asm("hlt");
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
274}
 
 
 
 
 
275
276static void parse_elf(void *output)
277{
278#ifdef CONFIG_X86_64
279	Elf64_Ehdr ehdr;
280	Elf64_Phdr *phdrs, *phdr;
281#else
282	Elf32_Ehdr ehdr;
283	Elf32_Phdr *phdrs, *phdr;
284#endif
285	void *dest;
286	int i;
287
288	memcpy(&ehdr, output, sizeof(ehdr));
289	if (ehdr.e_ident[EI_MAG0] != ELFMAG0 ||
290	   ehdr.e_ident[EI_MAG1] != ELFMAG1 ||
291	   ehdr.e_ident[EI_MAG2] != ELFMAG2 ||
292	   ehdr.e_ident[EI_MAG3] != ELFMAG3) {
293		error("Kernel is not a valid ELF file");
294		return;
295	}
296
297	if (!quiet)
298		putstr("Parsing ELF... ");
299
300	phdrs = malloc(sizeof(*phdrs) * ehdr.e_phnum);
301	if (!phdrs)
302		error("Failed to allocate space for phdrs");
303
304	memcpy(phdrs, output + ehdr.e_phoff, sizeof(*phdrs) * ehdr.e_phnum);
305
306	for (i = 0; i < ehdr.e_phnum; i++) {
307		phdr = &phdrs[i];
308
309		switch (phdr->p_type) {
310		case PT_LOAD:
311#ifdef CONFIG_RELOCATABLE
312			dest = output;
313			dest += (phdr->p_paddr - LOAD_PHYSICAL_ADDR);
314#else
315			dest = (void *)(phdr->p_paddr);
316#endif
317			memcpy(dest,
318			       output + phdr->p_offset,
319			       phdr->p_filesz);
320			break;
321		default: /* Ignore other PT_* */ break;
322		}
323	}
 
 
324}
325
326asmlinkage void decompress_kernel(void *rmode, memptr heap,
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
327				  unsigned char *input_data,
328				  unsigned long input_len,
329				  unsigned char *output)
 
330{
331	real_mode = rmode;
 
 
 
 
332
333	if (cmdline_find_option_bool("quiet"))
334		quiet = 1;
335	if (cmdline_find_option_bool("debug"))
336		debug = 1;
337
338	if (real_mode->screen_info.orig_video_mode == 7) {
 
 
339		vidmem = (char *) 0xb0000;
340		vidport = 0x3b4;
341	} else {
342		vidmem = (char *) 0xb8000;
343		vidport = 0x3d4;
344	}
345
346	lines = real_mode->screen_info.orig_video_lines;
347	cols = real_mode->screen_info.orig_video_cols;
348
349	console_init();
350	if (debug)
351		putstr("early console in decompress_kernel\n");
352
353	free_mem_ptr     = heap;	/* Heap */
354	free_mem_end_ptr = heap + BOOT_HEAP_SIZE;
355
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
356	if ((unsigned long)output & (MIN_KERNEL_ALIGN - 1))
357		error("Destination address inappropriately aligned");
 
 
358#ifdef CONFIG_X86_64
359	if (heap > 0x3fffffffffffUL)
360		error("Destination address too large");
361#else
362	if (heap > ((-__PAGE_OFFSET-(128<<20)-1) & 0x7fffffff))
363		error("Destination address too large");
364#endif
365#ifndef CONFIG_RELOCATABLE
366	if ((unsigned long)output != LOAD_PHYSICAL_ADDR)
367		error("Wrong destination address");
 
 
368#endif
369
370	if (!quiet)
371		putstr("\nDecompressing Linux... ");
372	decompress(input_data, input_len, NULL, NULL, output, NULL, error);
373	parse_elf(output);
374	if (!quiet)
375		putstr("done.\nBooting the kernel.\n");
376	return;
377}
v4.10.11
  1/*
  2 * misc.c
  3 *
  4 * This is a collection of several routines used to extract the kernel
  5 * which includes KASLR relocation, decompression, ELF parsing, and
  6 * relocation processing. Additionally included are the screen and serial
  7 * output functions and related debugging support functions.
  8 *
  9 * malloc by Hannu Savolainen 1993 and Matthias Urlichs 1994
 10 * puts by Nick Holloway 1993, better puts by Martin Mares 1995
 11 * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996
 12 */
 13
 14#include "misc.h"
 15#include "error.h"
 16#include "../string.h"
 17#include "../voffset.h"
 
 
 
 18
 19/*
 20 * WARNING!!
 21 * This code is compiled with -fPIC and it is relocated dynamically at
 22 * run time, but no relocation processing is performed. This means that
 23 * it is not safe to place pointers in static structures.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 24 */
 25
 26/* Macros used by the included decompressor code below. */
 
 
 27#define STATIC		static
 28
 29/*
 30 * Use normal definitions of mem*() from string.c. There are already
 31 * included header files which expect a definition of memset() and by
 32 * the time we define memset macro, it is too late.
 33 */
 34#undef memcpy
 35#undef memset
 36#define memzero(s, n)	memset((s), 0, (n))
 37#define memmove		memmove
 38
 39/* Functions used by the included decompressor code below. */
 40void *memmove(void *dest, const void *src, size_t n);
 41
 42/*
 43 * This is set up by the setup-routine at boot-time
 44 */
 45struct boot_params *boot_params;
 
 
 
 
 
 
 
 
 
 
 
 46
 47memptr free_mem_ptr;
 48memptr free_mem_end_ptr;
 49
 50static char *vidmem;
 51static int vidport;
 52static int lines, cols;
 53
 54#ifdef CONFIG_KERNEL_GZIP
 55#include "../../../../lib/decompress_inflate.c"
 56#endif
 57
 58#ifdef CONFIG_KERNEL_BZIP2
 59#include "../../../../lib/decompress_bunzip2.c"
 60#endif
 61
 62#ifdef CONFIG_KERNEL_LZMA
 63#include "../../../../lib/decompress_unlzma.c"
 64#endif
 65
 66#ifdef CONFIG_KERNEL_XZ
 67#include "../../../../lib/decompress_unxz.c"
 68#endif
 69
 70#ifdef CONFIG_KERNEL_LZO
 71#include "../../../../lib/decompress_unlzo.c"
 72#endif
 73
 74#ifdef CONFIG_KERNEL_LZ4
 75#include "../../../../lib/decompress_unlz4.c"
 76#endif
 77/*
 78 * NOTE: When adding a new decompressor, please update the analysis in
 79 * ../header.S.
 80 */
 81
 82static void scroll(void)
 83{
 84	int i;
 85
 86	memmove(vidmem, vidmem + cols * 2, (lines - 1) * cols * 2);
 87	for (i = (lines - 1) * cols * 2; i < lines * cols * 2; i += 2)
 88		vidmem[i] = ' ';
 89}
 90
 91#define XMTRDY          0x20
 92
 93#define TXR             0       /*  Transmit register (WRITE) */
 94#define LSR             5       /*  Line Status               */
 95static void serial_putchar(int ch)
 96{
 97	unsigned timeout = 0xffff;
 98
 99	while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
100		cpu_relax();
101
102	outb(ch, early_serial_base + TXR);
103}
104
105void __putstr(const char *s)
106{
107	int x, y, pos;
108	char c;
109
 
 
 
 
110	if (early_serial_base) {
111		const char *str = s;
112		while (*str) {
113			if (*str == '\n')
114				serial_putchar('\r');
115			serial_putchar(*str++);
116		}
117	}
118
119	if (boot_params->screen_info.orig_video_mode == 0 &&
120	    lines == 0 && cols == 0)
121		return;
122
123	x = boot_params->screen_info.orig_x;
124	y = boot_params->screen_info.orig_y;
125
126	while ((c = *s++) != '\0') {
127		if (c == '\n') {
128			x = 0;
129			if (++y >= lines) {
130				scroll();
131				y--;
132			}
133		} else {
134			vidmem[(x + cols * y) * 2] = c;
135			if (++x >= cols) {
136				x = 0;
137				if (++y >= lines) {
138					scroll();
139					y--;
140				}
141			}
142		}
143	}
144
145	boot_params->screen_info.orig_x = x;
146	boot_params->screen_info.orig_y = y;
147
148	pos = (x + cols * y) * 2;	/* Update cursor position */
149	outb(14, vidport);
150	outb(0xff & (pos >> 9), vidport+1);
151	outb(15, vidport);
152	outb(0xff & (pos >> 1), vidport+1);
153}
154
155void __puthex(unsigned long value)
156{
157	char alpha[2] = "0";
158	int bits;
159
160	for (bits = sizeof(value) * 8 - 4; bits >= 0; bits -= 4) {
161		unsigned long digit = (value >> bits) & 0xf;
 
 
 
 
 
 
 
 
 
 
 
 
 
162
163		if (digit < 0xA)
164			alpha[0] = '0' + digit;
165		else
166			alpha[0] = 'a' + (digit - 0xA);
 
 
 
 
 
 
 
 
 
167
168		__putstr(alpha);
169	}
170}
 
171
172#if CONFIG_X86_NEED_RELOCS
173static void handle_relocations(void *output, unsigned long output_len,
174			       unsigned long virt_addr)
175{
176	int *reloc;
177	unsigned long delta, map, ptr;
178	unsigned long min_addr = (unsigned long)output;
179	unsigned long max_addr = min_addr + (VO___bss_start - VO__text);
180
181	/*
182	 * Calculate the delta between where vmlinux was linked to load
183	 * and where it was actually loaded.
184	 */
185	delta = min_addr - LOAD_PHYSICAL_ADDR;
186
187	/*
188	 * The kernel contains a table of relocation addresses. Those
189	 * addresses have the final load address of the kernel in virtual
190	 * memory. We are currently working in the self map. So we need to
191	 * create an adjustment for kernel memory addresses to the self map.
192	 * This will involve subtracting out the base address of the kernel.
193	 */
194	map = delta - __START_KERNEL_map;
195
196	/*
197	 * 32-bit always performs relocations. 64-bit relocations are only
198	 * needed if KASLR has chosen a different starting address offset
199	 * from __START_KERNEL_map.
200	 */
201	if (IS_ENABLED(CONFIG_X86_64))
202		delta = virt_addr - LOAD_PHYSICAL_ADDR;
203
204	if (!delta) {
205		debug_putstr("No relocation needed... ");
206		return;
207	}
208	debug_putstr("Performing relocations... ");
209
210	/*
211	 * Process relocations: 32 bit relocations first then 64 bit after.
212	 * Three sets of binary relocations are added to the end of the kernel
213	 * before compression. Each relocation table entry is the kernel
214	 * address of the location which needs to be updated stored as a
215	 * 32-bit value which is sign extended to 64 bits.
216	 *
217	 * Format is:
218	 *
219	 * kernel bits...
220	 * 0 - zero terminator for 64 bit relocations
221	 * 64 bit relocation repeated
222	 * 0 - zero terminator for inverse 32 bit relocations
223	 * 32 bit inverse relocation repeated
224	 * 0 - zero terminator for 32 bit relocations
225	 * 32 bit relocation repeated
226	 *
227	 * So we work backwards from the end of the decompressed image.
228	 */
229	for (reloc = output + output_len - sizeof(*reloc); *reloc; reloc--) {
230		long extended = *reloc;
231		extended += map;
232
233		ptr = (unsigned long)extended;
234		if (ptr < min_addr || ptr > max_addr)
235			error("32-bit relocation outside of kernel!\n");
236
237		*(uint32_t *)ptr += delta;
238	}
239#ifdef CONFIG_X86_64
240	while (*--reloc) {
241		long extended = *reloc;
242		extended += map;
243
244		ptr = (unsigned long)extended;
245		if (ptr < min_addr || ptr > max_addr)
246			error("inverse 32-bit relocation outside of kernel!\n");
247
248		*(int32_t *)ptr -= delta;
249	}
250	for (reloc--; *reloc; reloc--) {
251		long extended = *reloc;
252		extended += map;
253
254		ptr = (unsigned long)extended;
255		if (ptr < min_addr || ptr > max_addr)
256			error("64-bit relocation outside of kernel!\n");
257
258		*(uint64_t *)ptr += delta;
259	}
260#endif
261}
262#else
263static inline void handle_relocations(void *output, unsigned long output_len,
264				      unsigned long virt_addr)
265{ }
266#endif
267
268static void parse_elf(void *output)
269{
270#ifdef CONFIG_X86_64
271	Elf64_Ehdr ehdr;
272	Elf64_Phdr *phdrs, *phdr;
273#else
274	Elf32_Ehdr ehdr;
275	Elf32_Phdr *phdrs, *phdr;
276#endif
277	void *dest;
278	int i;
279
280	memcpy(&ehdr, output, sizeof(ehdr));
281	if (ehdr.e_ident[EI_MAG0] != ELFMAG0 ||
282	   ehdr.e_ident[EI_MAG1] != ELFMAG1 ||
283	   ehdr.e_ident[EI_MAG2] != ELFMAG2 ||
284	   ehdr.e_ident[EI_MAG3] != ELFMAG3) {
285		error("Kernel is not a valid ELF file");
286		return;
287	}
288
289	debug_putstr("Parsing ELF... ");
 
290
291	phdrs = malloc(sizeof(*phdrs) * ehdr.e_phnum);
292	if (!phdrs)
293		error("Failed to allocate space for phdrs");
294
295	memcpy(phdrs, output + ehdr.e_phoff, sizeof(*phdrs) * ehdr.e_phnum);
296
297	for (i = 0; i < ehdr.e_phnum; i++) {
298		phdr = &phdrs[i];
299
300		switch (phdr->p_type) {
301		case PT_LOAD:
302#ifdef CONFIG_RELOCATABLE
303			dest = output;
304			dest += (phdr->p_paddr - LOAD_PHYSICAL_ADDR);
305#else
306			dest = (void *)(phdr->p_paddr);
307#endif
308			memmove(dest, output + phdr->p_offset, phdr->p_filesz);
 
 
309			break;
310		default: /* Ignore other PT_* */ break;
311		}
312	}
313
314	free(phdrs);
315}
316
317/*
318 * The compressed kernel image (ZO), has been moved so that its position
319 * is against the end of the buffer used to hold the uncompressed kernel
320 * image (VO) and the execution environment (.bss, .brk), which makes sure
321 * there is room to do the in-place decompression. (See header.S for the
322 * calculations.)
323 *
324 *                             |-----compressed kernel image------|
325 *                             V                                  V
326 * 0                       extract_offset                      +INIT_SIZE
327 * |-----------|---------------|-------------------------|--------|
328 *             |               |                         |        |
329 *           VO__text      startup_32 of ZO          VO__end    ZO__end
330 *             ^                                         ^
331 *             |-------uncompressed kernel image---------|
332 *
333 */
334asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
335				  unsigned char *input_data,
336				  unsigned long input_len,
337				  unsigned char *output,
338				  unsigned long output_len)
339{
340	const unsigned long kernel_total_size = VO__end - VO__text;
341	unsigned long virt_addr = (unsigned long)output;
342
343	/* Retain x86 boot parameters pointer passed from startup_32/64. */
344	boot_params = rmode;
345
346	/* Clear flags intended for solely in-kernel use. */
347	boot_params->hdr.loadflags &= ~KASLR_FLAG;
 
 
348
349	sanitize_boot_params(boot_params);
350
351	if (boot_params->screen_info.orig_video_mode == 7) {
352		vidmem = (char *) 0xb0000;
353		vidport = 0x3b4;
354	} else {
355		vidmem = (char *) 0xb8000;
356		vidport = 0x3d4;
357	}
358
359	lines = boot_params->screen_info.orig_video_lines;
360	cols = boot_params->screen_info.orig_video_cols;
361
362	console_init();
363	debug_putstr("early console in extract_kernel\n");
 
364
365	free_mem_ptr     = heap;	/* Heap */
366	free_mem_end_ptr = heap + BOOT_HEAP_SIZE;
367
368	/* Report initial kernel position details. */
369	debug_putaddr(input_data);
370	debug_putaddr(input_len);
371	debug_putaddr(output);
372	debug_putaddr(output_len);
373	debug_putaddr(kernel_total_size);
374
375	/*
376	 * The memory hole needed for the kernel is the larger of either
377	 * the entire decompressed kernel plus relocation table, or the
378	 * entire decompressed kernel plus .bss and .brk sections.
379	 */
380	choose_random_location((unsigned long)input_data, input_len,
381				(unsigned long *)&output,
382				max(output_len, kernel_total_size),
383				&virt_addr);
384
385	/* Validate memory location choices. */
386	if ((unsigned long)output & (MIN_KERNEL_ALIGN - 1))
387		error("Destination physical address inappropriately aligned");
388	if (virt_addr & (MIN_KERNEL_ALIGN - 1))
389		error("Destination virtual address inappropriately aligned");
390#ifdef CONFIG_X86_64
391	if (heap > 0x3fffffffffffUL)
392		error("Destination address too large");
393#else
394	if (heap > ((-__PAGE_OFFSET-(128<<20)-1) & 0x7fffffff))
395		error("Destination address too large");
396#endif
397#ifndef CONFIG_RELOCATABLE
398	if ((unsigned long)output != LOAD_PHYSICAL_ADDR)
399		error("Destination address does not match LOAD_PHYSICAL_ADDR");
400	if ((unsigned long)output != virt_addr)
401		error("Destination virtual address changed when not relocatable");
402#endif
403
404	debug_putstr("\nDecompressing Linux... ");
405	__decompress(input_data, input_len, NULL, NULL, output, output_len,
406			NULL, error);
407	parse_elf(output);
408	handle_relocations(output, output_len, virt_addr);
409	debug_putstr("done.\nBooting the kernel.\n");
410	return output;
411}