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v3.15
 
  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#include "../string.h"
 14
 15/* WARNING!!
 16 * This code is compiled with -fPIC and it is relocated dynamically
 17 * at run time, but no relocation processing is performed.
 18 * This means that it is not safe to place pointers in static structures.
 19 */
 20
 21/*
 22 * Getting to provable safe in place decompression is hard.
 23 * Worst case behaviours need to be analyzed.
 24 * Background information:
 25 *
 26 * The file layout is:
 27 *    magic[2]
 28 *    method[1]
 29 *    flags[1]
 30 *    timestamp[4]
 31 *    extraflags[1]
 32 *    os[1]
 33 *    compressed data blocks[N]
 34 *    crc[4] orig_len[4]
 35 *
 36 * resulting in 18 bytes of non compressed data overhead.
 37 *
 38 * Files divided into blocks
 39 * 1 bit (last block flag)
 40 * 2 bits (block type)
 41 *
 42 * 1 block occurs every 32K -1 bytes or when there 50% compression
 43 * has been achieved. The smallest block type encoding is always used.
 44 *
 45 * stored:
 46 *    32 bits length in bytes.
 47 *
 48 * fixed:
 49 *    magic fixed tree.
 50 *    symbols.
 51 *
 52 * dynamic:
 53 *    dynamic tree encoding.
 54 *    symbols.
 55 *
 56 *
 57 * The buffer for decompression in place is the length of the
 58 * uncompressed data, plus a small amount extra to keep the algorithm safe.
 59 * The compressed data is placed at the end of the buffer.  The output
 60 * pointer is placed at the start of the buffer and the input pointer
 61 * is placed where the compressed data starts.  Problems will occur
 62 * when the output pointer overruns the input pointer.
 63 *
 64 * The output pointer can only overrun the input pointer if the input
 65 * pointer is moving faster than the output pointer.  A condition only
 66 * triggered by data whose compressed form is larger than the uncompressed
 67 * form.
 68 *
 69 * The worst case at the block level is a growth of the compressed data
 70 * of 5 bytes per 32767 bytes.
 71 *
 72 * The worst case internal to a compressed block is very hard to figure.
 73 * The worst case can at least be boundined by having one bit that represents
 74 * 32764 bytes and then all of the rest of the bytes representing the very
 75 * very last byte.
 76 *
 77 * All of which is enough to compute an amount of extra data that is required
 78 * to be safe.  To avoid problems at the block level allocating 5 extra bytes
 79 * per 32767 bytes of data is sufficient.  To avoind problems internal to a
 80 * block adding an extra 32767 bytes (the worst case uncompressed block size)
 81 * is sufficient, to ensure that in the worst case the decompressed data for
 82 * block will stop the byte before the compressed data for a block begins.
 83 * To avoid problems with the compressed data's meta information an extra 18
 84 * bytes are needed.  Leading to the formula:
 85 *
 86 * extra_bytes = (uncompressed_size >> 12) + 32768 + 18 + decompressor_size.
 87 *
 88 * Adding 8 bytes per 32K is a bit excessive but much easier to calculate.
 89 * Adding 32768 instead of 32767 just makes for round numbers.
 90 * Adding the decompressor_size is necessary as it musht live after all
 91 * of the data as well.  Last I measured the decompressor is about 14K.
 92 * 10K of actual data and 4K of bss.
 93 *
 94 */
 95
 96/*
 97 * gzip declarations
 98 */
 99#define STATIC		static
100
101#undef memcpy
102
103/*
104 * Use a normal definition of memset() from string.c. There are already
105 * included header files which expect a definition of memset() and by
106 * the time we define memset macro, it is too late.
107 */
108#undef memset
109#define memzero(s, n)	memset((s), 0, (n))
 
110
111
112static void error(char *m);
113
114/*
115 * This is set up by the setup-routine at boot-time
116 */
117struct boot_params *real_mode;		/* Pointer to real-mode data */
118
119memptr free_mem_ptr;
120memptr free_mem_end_ptr;
121
122static char *vidmem;
123static int vidport;
124static int lines, cols;
125
126#ifdef CONFIG_KERNEL_GZIP
127#include "../../../../lib/decompress_inflate.c"
128#endif
129
130#ifdef CONFIG_KERNEL_BZIP2
131#include "../../../../lib/decompress_bunzip2.c"
132#endif
133
134#ifdef CONFIG_KERNEL_LZMA
135#include "../../../../lib/decompress_unlzma.c"
136#endif
137
138#ifdef CONFIG_KERNEL_XZ
139#include "../../../../lib/decompress_unxz.c"
140#endif
141
142#ifdef CONFIG_KERNEL_LZO
143#include "../../../../lib/decompress_unlzo.c"
144#endif
145
146#ifdef CONFIG_KERNEL_LZ4
147#include "../../../../lib/decompress_unlz4.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(const char *s)
174{
175	int x, y, pos;
176	char c;
177
178	if (early_serial_base) {
179		const char *str = s;
180		while (*str) {
181			if (*str == '\n')
182				serial_putchar('\r');
183			serial_putchar(*str++);
184		}
185	}
186
187	if (real_mode->screen_info.orig_video_mode == 0 &&
188	    lines == 0 && cols == 0)
189		return;
190
191	x = real_mode->screen_info.orig_x;
192	y = real_mode->screen_info.orig_y;
193
194	while ((c = *s++) != '\0') {
195		if (c == '\n') {
196			x = 0;
197			if (++y >= lines) {
198				scroll();
199				y--;
200			}
201		} else {
202			vidmem[(x + cols * y) * 2] = c;
203			if (++x >= cols) {
204				x = 0;
205				if (++y >= lines) {
206					scroll();
207					y--;
208				}
209			}
210		}
211	}
212
213	real_mode->screen_info.orig_x = x;
214	real_mode->screen_info.orig_y = y;
215
216	pos = (x + cols * y) * 2;	/* Update cursor position */
217	outb(14, vidport);
218	outb(0xff & (pos >> 9), vidport+1);
219	outb(15, vidport);
220	outb(0xff & (pos >> 1), vidport+1);
221}
222
223static void error(char *x)
224{
225	error_putstr("\n\n");
226	error_putstr(x);
227	error_putstr("\n\n -- System halted");
 
 
 
 
 
 
 
228
229	while (1)
230		asm("hlt");
231}
232
233#if CONFIG_X86_NEED_RELOCS
234static void handle_relocations(void *output, unsigned long output_len)
 
235{
236	int *reloc;
237	unsigned long delta, map, ptr;
238	unsigned long min_addr = (unsigned long)output;
239	unsigned long max_addr = min_addr + output_len;
240
241	/*
242	 * Calculate the delta between where vmlinux was linked to load
243	 * and where it was actually loaded.
244	 */
245	delta = min_addr - LOAD_PHYSICAL_ADDR;
246	if (!delta) {
247		debug_putstr("No relocation needed... ");
248		return;
249	}
250	debug_putstr("Performing relocations... ");
251
252	/*
253	 * The kernel contains a table of relocation addresses. Those
254	 * addresses have the final load address of the kernel in virtual
255	 * memory. We are currently working in the self map. So we need to
256	 * create an adjustment for kernel memory addresses to the self map.
257	 * This will involve subtracting out the base address of the kernel.
258	 */
259	map = delta - __START_KERNEL_map;
260
261	/*
 
 
 
 
 
 
 
 
 
 
 
 
 
 
262	 * Process relocations: 32 bit relocations first then 64 bit after.
263	 * Two sets of binary relocations are added to the end of the kernel
264	 * before compression. Each relocation table entry is the kernel
265	 * address of the location which needs to be updated stored as a
266	 * 32-bit value which is sign extended to 64 bits.
267	 *
268	 * Format is:
269	 *
270	 * kernel bits...
271	 * 0 - zero terminator for 64 bit relocations
272	 * 64 bit relocation repeated
 
 
273	 * 0 - zero terminator for 32 bit relocations
274	 * 32 bit relocation repeated
275	 *
276	 * So we work backwards from the end of the decompressed image.
277	 */
278	for (reloc = output + output_len - sizeof(*reloc); *reloc; reloc--) {
279		int extended = *reloc;
280		extended += map;
281
282		ptr = (unsigned long)extended;
283		if (ptr < min_addr || ptr > max_addr)
284			error("32-bit relocation outside of kernel!\n");
285
286		*(uint32_t *)ptr += delta;
287	}
288#ifdef CONFIG_X86_64
 
 
 
 
 
 
 
 
 
 
289	for (reloc--; *reloc; reloc--) {
290		long extended = *reloc;
291		extended += map;
292
293		ptr = (unsigned long)extended;
294		if (ptr < min_addr || ptr > max_addr)
295			error("64-bit relocation outside of kernel!\n");
296
297		*(uint64_t *)ptr += delta;
298	}
299#endif
300}
301#else
302static inline void handle_relocations(void *output, unsigned long output_len)
 
303{ }
304#endif
305
306static void parse_elf(void *output)
307{
308#ifdef CONFIG_X86_64
309	Elf64_Ehdr ehdr;
310	Elf64_Phdr *phdrs, *phdr;
311#else
312	Elf32_Ehdr ehdr;
313	Elf32_Phdr *phdrs, *phdr;
314#endif
315	void *dest;
316	int i;
317
318	memcpy(&ehdr, output, sizeof(ehdr));
319	if (ehdr.e_ident[EI_MAG0] != ELFMAG0 ||
320	   ehdr.e_ident[EI_MAG1] != ELFMAG1 ||
321	   ehdr.e_ident[EI_MAG2] != ELFMAG2 ||
322	   ehdr.e_ident[EI_MAG3] != ELFMAG3) {
323		error("Kernel is not a valid ELF file");
324		return;
325	}
326
327	debug_putstr("Parsing ELF... ");
328
329	phdrs = malloc(sizeof(*phdrs) * ehdr.e_phnum);
330	if (!phdrs)
331		error("Failed to allocate space for phdrs");
332
333	memcpy(phdrs, output + ehdr.e_phoff, sizeof(*phdrs) * ehdr.e_phnum);
334
335	for (i = 0; i < ehdr.e_phnum; i++) {
336		phdr = &phdrs[i];
337
338		switch (phdr->p_type) {
339		case PT_LOAD:
 
 
 
 
340#ifdef CONFIG_RELOCATABLE
341			dest = output;
342			dest += (phdr->p_paddr - LOAD_PHYSICAL_ADDR);
343#else
344			dest = (void *)(phdr->p_paddr);
345#endif
346			memcpy(dest,
347			       output + phdr->p_offset,
348			       phdr->p_filesz);
349			break;
350		default: /* Ignore other PT_* */ break;
351		}
352	}
353
354	free(phdrs);
355}
356
357asmlinkage __visible void *decompress_kernel(void *rmode, memptr heap,
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
358				  unsigned char *input_data,
359				  unsigned long input_len,
360				  unsigned char *output,
361				  unsigned long output_len)
362{
363	real_mode = rmode;
 
 
 
 
 
 
 
 
364
365	sanitize_boot_params(real_mode);
366
367	if (real_mode->screen_info.orig_video_mode == 7) {
368		vidmem = (char *) 0xb0000;
369		vidport = 0x3b4;
370	} else {
371		vidmem = (char *) 0xb8000;
372		vidport = 0x3d4;
373	}
374
375	lines = real_mode->screen_info.orig_video_lines;
376	cols = real_mode->screen_info.orig_video_cols;
377
378	console_init();
379	debug_putstr("early console in decompress_kernel\n");
 
 
 
 
 
 
 
 
380
381	free_mem_ptr     = heap;	/* Heap */
382	free_mem_end_ptr = heap + BOOT_HEAP_SIZE;
383
384	output = choose_kernel_location(input_data, input_len,
385					output, output_len);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
386
387	/* Validate memory location choices. */
388	if ((unsigned long)output & (MIN_KERNEL_ALIGN - 1))
389		error("Destination 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("Wrong destination address");
400#endif
401
402	debug_putstr("\nDecompressing Linux... ");
403	decompress(input_data, input_len, NULL, NULL, output, NULL, error);
 
404	parse_elf(output);
405	handle_relocations(output, output_len);
406	debug_putstr("done.\nBooting the kernel.\n");
 
 
 
 
407	return output;
 
 
 
 
 
408}
v5.14.15
  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * misc.c
  4 *
  5 * This is a collection of several routines used to extract the kernel
  6 * which includes KASLR relocation, decompression, ELF parsing, and
  7 * relocation processing. Additionally included are the screen and serial
  8 * output functions and related debugging support functions.
  9 *
 10 * malloc by Hannu Savolainen 1993 and Matthias Urlichs 1994
 11 * puts by Nick Holloway 1993, better puts by Martin Mares 1995
 12 * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996
 13 */
 14
 15#include "misc.h"
 16#include "error.h"
 17#include "pgtable.h"
 18#include "../string.h"
 19#include "../voffset.h"
 20#include <asm/bootparam_utils.h>
 
 
 
 
 21
 22/*
 23 * WARNING!!
 24 * This code is compiled with -fPIC and it is relocated dynamically at
 25 * run time, but no relocation processing is performed. This means that
 26 * it is not safe to place pointers in static structures.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 27 */
 28
 29/* Macros used by the included decompressor code below. */
 
 
 30#define STATIC		static
 31
 
 
 32/*
 33 * Provide definitions of memzero and memmove as some of the decompressors will
 34 * try to define their own functions if these are not defined as macros.
 
 35 */
 
 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#ifdef CONFIG_KERNEL_ZSTD
 79#include "../../../../lib/decompress_unzstd.c"
 80#endif
 81/*
 82 * NOTE: When adding a new decompressor, please update the analysis in
 83 * ../header.S.
 84 */
 85
 86static void scroll(void)
 87{
 88	int i;
 89
 90	memmove(vidmem, vidmem + cols * 2, (lines - 1) * cols * 2);
 91	for (i = (lines - 1) * cols * 2; i < lines * cols * 2; i += 2)
 92		vidmem[i] = ' ';
 93}
 94
 95#define XMTRDY          0x20
 96
 97#define TXR             0       /*  Transmit register (WRITE) */
 98#define LSR             5       /*  Line Status               */
 99static void serial_putchar(int ch)
100{
101	unsigned timeout = 0xffff;
102
103	while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
104		cpu_relax();
105
106	outb(ch, early_serial_base + TXR);
107}
108
109void __putstr(const char *s)
110{
111	int x, y, pos;
112	char c;
113
114	if (early_serial_base) {
115		const char *str = s;
116		while (*str) {
117			if (*str == '\n')
118				serial_putchar('\r');
119			serial_putchar(*str++);
120		}
121	}
122
123	if (lines == 0 || cols == 0)
 
124		return;
125
126	x = boot_params->screen_info.orig_x;
127	y = boot_params->screen_info.orig_y;
128
129	while ((c = *s++) != '\0') {
130		if (c == '\n') {
131			x = 0;
132			if (++y >= lines) {
133				scroll();
134				y--;
135			}
136		} else {
137			vidmem[(x + cols * y) * 2] = c;
138			if (++x >= cols) {
139				x = 0;
140				if (++y >= lines) {
141					scroll();
142					y--;
143				}
144			}
145		}
146	}
147
148	boot_params->screen_info.orig_x = x;
149	boot_params->screen_info.orig_y = y;
150
151	pos = (x + cols * y) * 2;	/* Update cursor position */
152	outb(14, vidport);
153	outb(0xff & (pos >> 9), vidport+1);
154	outb(15, vidport);
155	outb(0xff & (pos >> 1), vidport+1);
156}
157
158void __puthex(unsigned long value)
159{
160	char alpha[2] = "0";
161	int bits;
162
163	for (bits = sizeof(value) * 8 - 4; bits >= 0; bits -= 4) {
164		unsigned long digit = (value >> bits) & 0xf;
165
166		if (digit < 0xA)
167			alpha[0] = '0' + digit;
168		else
169			alpha[0] = 'a' + (digit - 0xA);
170
171		__putstr(alpha);
172	}
173}
174
175#ifdef CONFIG_X86_NEED_RELOCS
176static void handle_relocations(void *output, unsigned long output_len,
177			       unsigned long virt_addr)
178{
179	int *reloc;
180	unsigned long delta, map, ptr;
181	unsigned long min_addr = (unsigned long)output;
182	unsigned long max_addr = min_addr + (VO___bss_start - VO__text);
183
184	/*
185	 * Calculate the delta between where vmlinux was linked to load
186	 * and where it was actually loaded.
187	 */
188	delta = min_addr - LOAD_PHYSICAL_ADDR;
 
 
 
 
 
189
190	/*
191	 * The kernel contains a table of relocation addresses. Those
192	 * addresses have the final load address of the kernel in virtual
193	 * memory. We are currently working in the self map. So we need to
194	 * create an adjustment for kernel memory addresses to the self map.
195	 * This will involve subtracting out the base address of the kernel.
196	 */
197	map = delta - __START_KERNEL_map;
198
199	/*
200	 * 32-bit always performs relocations. 64-bit relocations are only
201	 * needed if KASLR has chosen a different starting address offset
202	 * from __START_KERNEL_map.
203	 */
204	if (IS_ENABLED(CONFIG_X86_64))
205		delta = virt_addr - LOAD_PHYSICAL_ADDR;
206
207	if (!delta) {
208		debug_putstr("No relocation needed... ");
209		return;
210	}
211	debug_putstr("Performing relocations... ");
212
213	/*
214	 * Process relocations: 32 bit relocations first then 64 bit after.
215	 * Three sets of binary relocations are added to the end of the kernel
216	 * before compression. Each relocation table entry is the kernel
217	 * address of the location which needs to be updated stored as a
218	 * 32-bit value which is sign extended to 64 bits.
219	 *
220	 * Format is:
221	 *
222	 * kernel bits...
223	 * 0 - zero terminator for 64 bit relocations
224	 * 64 bit relocation repeated
225	 * 0 - zero terminator for inverse 32 bit relocations
226	 * 32 bit inverse relocation repeated
227	 * 0 - zero terminator for 32 bit relocations
228	 * 32 bit relocation repeated
229	 *
230	 * So we work backwards from the end of the decompressed image.
231	 */
232	for (reloc = output + output_len - sizeof(*reloc); *reloc; reloc--) {
233		long extended = *reloc;
234		extended += map;
235
236		ptr = (unsigned long)extended;
237		if (ptr < min_addr || ptr > max_addr)
238			error("32-bit relocation outside of kernel!\n");
239
240		*(uint32_t *)ptr += delta;
241	}
242#ifdef CONFIG_X86_64
243	while (*--reloc) {
244		long extended = *reloc;
245		extended += map;
246
247		ptr = (unsigned long)extended;
248		if (ptr < min_addr || ptr > max_addr)
249			error("inverse 32-bit relocation outside of kernel!\n");
250
251		*(int32_t *)ptr -= delta;
252	}
253	for (reloc--; *reloc; reloc--) {
254		long extended = *reloc;
255		extended += map;
256
257		ptr = (unsigned long)extended;
258		if (ptr < min_addr || ptr > max_addr)
259			error("64-bit relocation outside of kernel!\n");
260
261		*(uint64_t *)ptr += delta;
262	}
263#endif
264}
265#else
266static inline void handle_relocations(void *output, unsigned long output_len,
267				      unsigned long virt_addr)
268{ }
269#endif
270
271static void parse_elf(void *output)
272{
273#ifdef CONFIG_X86_64
274	Elf64_Ehdr ehdr;
275	Elf64_Phdr *phdrs, *phdr;
276#else
277	Elf32_Ehdr ehdr;
278	Elf32_Phdr *phdrs, *phdr;
279#endif
280	void *dest;
281	int i;
282
283	memcpy(&ehdr, output, sizeof(ehdr));
284	if (ehdr.e_ident[EI_MAG0] != ELFMAG0 ||
285	   ehdr.e_ident[EI_MAG1] != ELFMAG1 ||
286	   ehdr.e_ident[EI_MAG2] != ELFMAG2 ||
287	   ehdr.e_ident[EI_MAG3] != ELFMAG3) {
288		error("Kernel is not a valid ELF file");
289		return;
290	}
291
292	debug_putstr("Parsing ELF... ");
293
294	phdrs = malloc(sizeof(*phdrs) * ehdr.e_phnum);
295	if (!phdrs)
296		error("Failed to allocate space for phdrs");
297
298	memcpy(phdrs, output + ehdr.e_phoff, sizeof(*phdrs) * ehdr.e_phnum);
299
300	for (i = 0; i < ehdr.e_phnum; i++) {
301		phdr = &phdrs[i];
302
303		switch (phdr->p_type) {
304		case PT_LOAD:
305#ifdef CONFIG_X86_64
306			if ((phdr->p_align % 0x200000) != 0)
307				error("Alignment of LOAD segment isn't multiple of 2MB");
308#endif
309#ifdef CONFIG_RELOCATABLE
310			dest = output;
311			dest += (phdr->p_paddr - LOAD_PHYSICAL_ADDR);
312#else
313			dest = (void *)(phdr->p_paddr);
314#endif
315			memmove(dest, output + phdr->p_offset, phdr->p_filesz);
 
 
316			break;
317		default: /* Ignore other PT_* */ break;
318		}
319	}
320
321	free(phdrs);
322}
323
324/*
325 * The compressed kernel image (ZO), has been moved so that its position
326 * is against the end of the buffer used to hold the uncompressed kernel
327 * image (VO) and the execution environment (.bss, .brk), which makes sure
328 * there is room to do the in-place decompression. (See header.S for the
329 * calculations.)
330 *
331 *                             |-----compressed kernel image------|
332 *                             V                                  V
333 * 0                       extract_offset                      +INIT_SIZE
334 * |-----------|---------------|-------------------------|--------|
335 *             |               |                         |        |
336 *           VO__text      startup_32 of ZO          VO__end    ZO__end
337 *             ^                                         ^
338 *             |-------uncompressed kernel image---------|
339 *
340 */
341asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
342				  unsigned char *input_data,
343				  unsigned long input_len,
344				  unsigned char *output,
345				  unsigned long output_len)
346{
347	const unsigned long kernel_total_size = VO__end - VO__text;
348	unsigned long virt_addr = LOAD_PHYSICAL_ADDR;
349	unsigned long needed_size;
350
351	/* Retain x86 boot parameters pointer passed from startup_32/64. */
352	boot_params = rmode;
353
354	/* Clear flags intended for solely in-kernel use. */
355	boot_params->hdr.loadflags &= ~KASLR_FLAG;
356
357	sanitize_boot_params(boot_params);
358
359	if (boot_params->screen_info.orig_video_mode == 7) {
360		vidmem = (char *) 0xb0000;
361		vidport = 0x3b4;
362	} else {
363		vidmem = (char *) 0xb8000;
364		vidport = 0x3d4;
365	}
366
367	lines = boot_params->screen_info.orig_video_lines;
368	cols = boot_params->screen_info.orig_video_cols;
369
370	console_init();
371
372	/*
373	 * Save RSDP address for later use. Have this after console_init()
374	 * so that early debugging output from the RSDP parsing code can be
375	 * collected.
376	 */
377	boot_params->acpi_rsdp_addr = get_rsdp_addr();
378
379	debug_putstr("early console in extract_kernel\n");
380
381	free_mem_ptr     = heap;	/* Heap */
382	free_mem_end_ptr = heap + BOOT_HEAP_SIZE;
383
384	/*
385	 * The memory hole needed for the kernel is the larger of either
386	 * the entire decompressed kernel plus relocation table, or the
387	 * entire decompressed kernel plus .bss and .brk sections.
388	 *
389	 * On X86_64, the memory is mapped with PMD pages. Round the
390	 * size up so that the full extent of PMD pages mapped is
391	 * included in the check against the valid memory table
392	 * entries. This ensures the full mapped area is usable RAM
393	 * and doesn't include any reserved areas.
394	 */
395	needed_size = max(output_len, kernel_total_size);
396#ifdef CONFIG_X86_64
397	needed_size = ALIGN(needed_size, MIN_KERNEL_ALIGN);
398#endif
399
400	/* Report initial kernel position details. */
401	debug_putaddr(input_data);
402	debug_putaddr(input_len);
403	debug_putaddr(output);
404	debug_putaddr(output_len);
405	debug_putaddr(kernel_total_size);
406	debug_putaddr(needed_size);
407
408#ifdef CONFIG_X86_64
409	/* Report address of 32-bit trampoline */
410	debug_putaddr(trampoline_32bit);
411#endif
412
413	choose_random_location((unsigned long)input_data, input_len,
414				(unsigned long *)&output,
415				needed_size,
416				&virt_addr);
417
418	/* Validate memory location choices. */
419	if ((unsigned long)output & (MIN_KERNEL_ALIGN - 1))
420		error("Destination physical address inappropriately aligned");
421	if (virt_addr & (MIN_KERNEL_ALIGN - 1))
422		error("Destination virtual address inappropriately aligned");
423#ifdef CONFIG_X86_64
424	if (heap > 0x3fffffffffffUL)
425		error("Destination address too large");
426	if (virt_addr + max(output_len, kernel_total_size) > KERNEL_IMAGE_SIZE)
427		error("Destination virtual address is beyond the kernel mapping area");
428#else
429	if (heap > ((-__PAGE_OFFSET-(128<<20)-1) & 0x7fffffff))
430		error("Destination address too large");
431#endif
432#ifndef CONFIG_RELOCATABLE
433	if (virt_addr != LOAD_PHYSICAL_ADDR)
434		error("Destination virtual address changed when not relocatable");
435#endif
436
437	debug_putstr("\nDecompressing Linux... ");
438	__decompress(input_data, input_len, NULL, NULL, output, output_len,
439			NULL, error);
440	parse_elf(output);
441	handle_relocations(output, output_len, virt_addr);
442	debug_putstr("done.\nBooting the kernel.\n");
443
444	/* Disable exception handling before booting the kernel */
445	cleanup_exception_handling();
446
447	return output;
448}
449
450void fortify_panic(const char *name)
451{
452	error("detected buffer overflow");
453}