arch/x86/boot/compressed/misc.c - linux/kernel/git/bpf/bpf - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * misc.c
  *
  * This is a collection of several routines used to extract the kernel
  * which includes KASLR relocation, decompression, ELF parsing, and
  * relocation processing. Additionally included are the screen and serial
  * output functions and related debugging support functions.
  *
  * malloc by Hannu Savolainen 1993 and Matthias Urlichs 1994
  * puts by Nick Holloway 1993, better puts by Martin Mares 1995
  * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996
  */

 #include "misc.h"
 #include "error.h"
 #include "pgtable.h"
 #include "../string.h"
 #include "../voffset.h"
 #include <asm/bootparam_utils.h>

 /*
  * WARNING!!
  * This code is compiled with -fPIC and it is relocated dynamically at
  * run time, but no relocation processing is performed. This means that
  * it is not safe to place pointers in static structures.
  */

 /* Macros used by the included decompressor code below. */
 #define STATIC		static

 /*
  * Use normal definitions of mem*() from string.c. There are already
  * included header files which expect a definition of memset() and by
  * the time we define memset macro, it is too late.
  */
 #undef memcpy
 #undef memset
 #define memzero(s, n)	memset((s), 0, (n))
 #define memmove		memmove

 /* Functions used by the included decompressor code below. */
 void *memmove(void *dest, const void *src, size_t n);

 /*
  * This is set up by the setup-routine at boot-time
  */
 struct boot_params *boot_params;

 memptr free_mem_ptr;
 memptr free_mem_end_ptr;

 static char *vidmem;
 static int vidport;
 static int lines, cols;

 #ifdef CONFIG_KERNEL_GZIP
 #include "../../../../lib/decompress_inflate.c"
 #endif

 #ifdef CONFIG_KERNEL_BZIP2
 #include "../../../../lib/decompress_bunzip2.c"
 #endif

 #ifdef CONFIG_KERNEL_LZMA
 #include "../../../../lib/decompress_unlzma.c"
 #endif

 #ifdef CONFIG_KERNEL_XZ
 #include "../../../../lib/decompress_unxz.c"
 #endif

 #ifdef CONFIG_KERNEL_LZO
 #include "../../../../lib/decompress_unlzo.c"
 #endif

 #ifdef CONFIG_KERNEL_LZ4
 #include "../../../../lib/decompress_unlz4.c"
 #endif
 /*
  * NOTE: When adding a new decompressor, please update the analysis in
  * ../header.S.
  */

 static void scroll(void)
 {
 	int i;

 	memmove(vidmem, vidmem + cols * 2, (lines - 1) * cols * 2);
 	for (i = (lines - 1) * cols * 2; i < lines * cols * 2; i += 2)
 		vidmem[i] = ' ';
 }

 #define XMTRDY          0x20

 #define TXR             0       /*  Transmit register (WRITE) */
 #define LSR             5       /*  Line Status               */
 static void serial_putchar(int ch)
 {
 	unsigned timeout = 0xffff;

 	while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
 		cpu_relax();

 	outb(ch, early_serial_base + TXR);
 }

 void __putstr(const char *s)
 {
 	int x, y, pos;
 	char c;

 	if (early_serial_base) {
 		const char *str = s;
 		while (*str) {
 			if (*str == '\n')
 				serial_putchar('\r');
 			serial_putchar(*str++);
 		}
 	}

 	if (lines == 0 || cols == 0)
 		return;

 	x = boot_params->screen_info.orig_x;
 	y = boot_params->screen_info.orig_y;

 	while ((c = *s++) != '\0') {
 		if (c == '\n') {
 			x = 0;
 			if (++y >= lines) {
 				scroll();
 				y--;
 			}
 		} else {
 			vidmem[(x + cols * y) * 2] = c;
 			if (++x >= cols) {
 				x = 0;
 				if (++y >= lines) {
 					scroll();
 					y--;
 				}
 			}
 		}
 	}

 	boot_params->screen_info.orig_x = x;
 	boot_params->screen_info.orig_y = y;

 	pos = (x + cols * y) * 2;	/* Update cursor position */
 	outb(14, vidport);
 	outb(0xff & (pos >> 9), vidport+1);
 	outb(15, vidport);
 	outb(0xff & (pos >> 1), vidport+1);
 }

 void __puthex(unsigned long value)
 {
 	char alpha[2] = "0";
 	int bits;

 	for (bits = sizeof(value) * 8 - 4; bits >= 0; bits -= 4) {
 		unsigned long digit = (value >> bits) & 0xf;

 		if (digit < 0xA)
 			alpha[0] = '0' + digit;
 		else
 			alpha[0] = 'a' + (digit - 0xA);

 		__putstr(alpha);
 	}
 }

 #if CONFIG_X86_NEED_RELOCS
 static void handle_relocations(void *output, unsigned long output_len,
 			       unsigned long virt_addr)
 {
 	int *reloc;
 	unsigned long delta, map, ptr;
 	unsigned long min_addr = (unsigned long)output;
 	unsigned long max_addr = min_addr + (VO___bss_start - VO__text);

 	/*
 	 * Calculate the delta between where vmlinux was linked to load
 	 * and where it was actually loaded.
 	 */
 	delta = min_addr - LOAD_PHYSICAL_ADDR;

 	/*
 	 * The kernel contains a table of relocation addresses. Those
 	 * addresses have the final load address of the kernel in virtual
 	 * memory. We are currently working in the self map. So we need to
 	 * create an adjustment for kernel memory addresses to the self map.
 	 * This will involve subtracting out the base address of the kernel.
 	 */
 	map = delta - __START_KERNEL_map;

 	/*
 	 * 32-bit always performs relocations. 64-bit relocations are only
 	 * needed if KASLR has chosen a different starting address offset
 	 * from __START_KERNEL_map.
 	 */
 	if (IS_ENABLED(CONFIG_X86_64))
 		delta = virt_addr - LOAD_PHYSICAL_ADDR;

 	if (!delta) {
 		debug_putstr("No relocation needed... ");
 		return;
 	}
 	debug_putstr("Performing relocations... ");

 	/*
 	 * Process relocations: 32 bit relocations first then 64 bit after.
 	 * Three sets of binary relocations are added to the end of the kernel
 	 * before compression. Each relocation table entry is the kernel
 	 * address of the location which needs to be updated stored as a
 	 * 32-bit value which is sign extended to 64 bits.
 	 *
 	 * Format is:
 	 *
 	 * kernel bits...
 	 * 0 - zero terminator for 64 bit relocations
 	 * 64 bit relocation repeated
 	 * 0 - zero terminator for inverse 32 bit relocations
 	 * 32 bit inverse relocation repeated
 	 * 0 - zero terminator for 32 bit relocations
 	 * 32 bit relocation repeated
 	 *
 	 * So we work backwards from the end of the decompressed image.
 	 */
 	for (reloc = output + output_len - sizeof(*reloc); *reloc; reloc--) {
 		long extended = *reloc;
 		extended += map;

 		ptr = (unsigned long)extended;
 		if (ptr < min_addr || ptr > max_addr)
 			error("32-bit relocation outside of kernel!\n");

 		*(uint32_t *)ptr += delta;
 	}
 #ifdef CONFIG_X86_64
 	while (*--reloc) {
 		long extended = *reloc;
 		extended += map;

 		ptr = (unsigned long)extended;
 		if (ptr < min_addr || ptr > max_addr)
 			error("inverse 32-bit relocation outside of kernel!\n");

 		*(int32_t *)ptr -= delta;
 	}
 	for (reloc--; *reloc; reloc--) {
 		long extended = *reloc;
 		extended += map;

 		ptr = (unsigned long)extended;
 		if (ptr < min_addr || ptr > max_addr)
 			error("64-bit relocation outside of kernel!\n");

 		*(uint64_t *)ptr += delta;
 	}
 #endif
 }
 #else
 static inline void handle_relocations(void *output, unsigned long output_len,
 				      unsigned long virt_addr)
 { }
 #endif

 static void parse_elf(void *output)
 {
 #ifdef CONFIG_X86_64
 	Elf64_Ehdr ehdr;
 	Elf64_Phdr *phdrs, *phdr;
 #else
 	Elf32_Ehdr ehdr;
 	Elf32_Phdr *phdrs, *phdr;
 #endif
 	void *dest;
 	int i;

 	memcpy(&ehdr, output, sizeof(ehdr));
 	if (ehdr.e_ident[EI_MAG0] != ELFMAG0 ||
 	   ehdr.e_ident[EI_MAG1] != ELFMAG1 ||
 	   ehdr.e_ident[EI_MAG2] != ELFMAG2 ||
 	   ehdr.e_ident[EI_MAG3] != ELFMAG3) {
 		error("Kernel is not a valid ELF file");
 		return;
 	}

 	debug_putstr("Parsing ELF... ");

 	phdrs = malloc(sizeof(*phdrs) * ehdr.e_phnum);
 	if (!phdrs)
 		error("Failed to allocate space for phdrs");

 	memcpy(phdrs, output + ehdr.e_phoff, sizeof(*phdrs) * ehdr.e_phnum);

 	for (i = 0; i < ehdr.e_phnum; i++) {
 		phdr = &phdrs[i];

 		switch (phdr->p_type) {
 		case PT_LOAD:
 #ifdef CONFIG_X86_64
 			if ((phdr->p_align % 0x200000) != 0)
 				error("Alignment of LOAD segment isn't multiple of 2MB");
 #endif
 #ifdef CONFIG_RELOCATABLE
 			dest = output;
 			dest += (phdr->p_paddr - LOAD_PHYSICAL_ADDR);
 #else
 			dest = (void *)(phdr->p_paddr);
 #endif
 			memmove(dest, output + phdr->p_offset, phdr->p_filesz);
 			break;
 		default: /* Ignore other PT_* */ break;
 		}
 	}

 	free(phdrs);
 }

 /*
  * The compressed kernel image (ZO), has been moved so that its position
  * is against the end of the buffer used to hold the uncompressed kernel
  * image (VO) and the execution environment (.bss, .brk), which makes sure
  * there is room to do the in-place decompression. (See header.S for the
  * calculations.)
  *
  *                             |-----compressed kernel image------|
  *                             V                                  V
  * 0                       extract_offset                      +INIT_SIZE
  * |-----------|---------------|-------------------------|--------|
  *             |               |                         |        |
  *           VO__text      startup_32 of ZO          VO__end    ZO__end
  *             ^                                         ^
  *             |-------uncompressed kernel image---------|
  *
  */
 asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
 				  unsigned char *input_data,
 				  unsigned long input_len,
 				  unsigned char *output,
 				  unsigned long output_len)
 {
 	const unsigned long kernel_total_size = VO__end - VO__text;
 	unsigned long virt_addr = LOAD_PHYSICAL_ADDR;
 	unsigned long needed_size;

 	/* Retain x86 boot parameters pointer passed from startup_32/64. */
 	boot_params = rmode;

 	/* Clear flags intended for solely in-kernel use. */
 	boot_params->hdr.loadflags &= ~KASLR_FLAG;

 	sanitize_boot_params(boot_params);

 	if (boot_params->screen_info.orig_video_mode == 7) {
 		vidmem = (char *) 0xb0000;
 		vidport = 0x3b4;
 	} else {
 		vidmem = (char *) 0xb8000;
 		vidport = 0x3d4;
 	}

 	lines = boot_params->screen_info.orig_video_lines;
 	cols = boot_params->screen_info.orig_video_cols;

 	console_init();

 	/*
 	 * Save RSDP address for later use. Have this after console_init()
 	 * so that early debugging output from the RSDP parsing code can be
 	 * collected.
 	 */
 	boot_params->acpi_rsdp_addr = get_rsdp_addr();

 	debug_putstr("early console in extract_kernel\n");

 	free_mem_ptr     = heap;	/* Heap */
 	free_mem_end_ptr = heap + BOOT_HEAP_SIZE;

 	/*
 	 * The memory hole needed for the kernel is the larger of either
 	 * the entire decompressed kernel plus relocation table, or the
 	 * entire decompressed kernel plus .bss and .brk sections.
 	 *
 	 * On X86_64, the memory is mapped with PMD pages. Round the
 	 * size up so that the full extent of PMD pages mapped is
 	 * included in the check against the valid memory table
 	 * entries. This ensures the full mapped area is usable RAM
 	 * and doesn't include any reserved areas.
 	 */
 	needed_size = max(output_len, kernel_total_size);
 #ifdef CONFIG_X86_64
 	needed_size = ALIGN(needed_size, MIN_KERNEL_ALIGN);
 #endif

 	/* Report initial kernel position details. */
 	debug_putaddr(input_data);
 	debug_putaddr(input_len);
 	debug_putaddr(output);
 	debug_putaddr(output_len);
 	debug_putaddr(kernel_total_size);
 	debug_putaddr(needed_size);

 #ifdef CONFIG_X86_64
 	/* Report address of 32-bit trampoline */
 	debug_putaddr(trampoline_32bit);
 #endif

 	choose_random_location((unsigned long)input_data, input_len,
 				(unsigned long *)&output,
 				needed_size,
 				&virt_addr);

 	/* Validate memory location choices. */
 	if ((unsigned long)output & (MIN_KERNEL_ALIGN - 1))
 		error("Destination physical address inappropriately aligned");
 	if (virt_addr & (MIN_KERNEL_ALIGN - 1))
 		error("Destination virtual address inappropriately aligned");
 #ifdef CONFIG_X86_64
 	if (heap > 0x3fffffffffffUL)
 		error("Destination address too large");
 	if (virt_addr + max(output_len, kernel_total_size) > KERNEL_IMAGE_SIZE)
 		error("Destination virtual address is beyond the kernel mapping area");
 #else
 	if (heap > ((-__PAGE_OFFSET-(128<<20)-1) & 0x7fffffff))
 		error("Destination address too large");
 #endif
 #ifndef CONFIG_RELOCATABLE
 	if ((unsigned long)output != LOAD_PHYSICAL_ADDR)
 		error("Destination address does not match LOAD_PHYSICAL_ADDR");
 	if (virt_addr != LOAD_PHYSICAL_ADDR)
 		error("Destination virtual address changed when not relocatable");
 #endif

 	debug_putstr("\nDecompressing Linux... ");
 	__decompress(input_data, input_len, NULL, NULL, output, output_len,
 			NULL, error);
 	parse_elf(output);
 	handle_relocations(output, output_len, virt_addr);
 	debug_putstr("done.\nBooting the kernel.\n");
 	return output;
 }

 void fortify_panic(const char *name)
 {
 	error("detected buffer overflow");
 }
	// SPDX-License-Identifier: GPL-2.0
	/*
	* misc.c
	*
	* This is a collection of several routines used to extract the kernel
	* which includes KASLR relocation, decompression, ELF parsing, and
	* relocation processing. Additionally included are the screen and serial
	* output functions and related debugging support functions.
	*
	* malloc by Hannu Savolainen 1993 and Matthias Urlichs 1994
	* puts by Nick Holloway 1993, better puts by Martin Mares 1995
	* High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996
	*/

	#include "misc.h"
	#include "error.h"
	#include "pgtable.h"
	#include "../string.h"
	#include "../voffset.h"
	#include <asm/bootparam_utils.h>

	/*
	* WARNING!!
	* This code is compiled with -fPIC and it is relocated dynamically at
	* run time, but no relocation processing is performed. This means that
	* it is not safe to place pointers in static structures.
	*/

	/* Macros used by the included decompressor code below. */
	#define STATIC static

	/*
	* Use normal definitions of mem*() from string.c. There are already
	* included header files which expect a definition of memset() and by
	* the time we define memset macro, it is too late.
	*/
	#undef memcpy
	#undef memset
	#define memzero(s, n) memset((s), 0, (n))
	#define memmove memmove

	/* Functions used by the included decompressor code below. */
	void memmove(void dest, const void *src, size_t n);

	/*
	* This is set up by the setup-routine at boot-time
	*/
	struct boot_params *boot_params;

	memptr free_mem_ptr;
	memptr free_mem_end_ptr;

	static char *vidmem;
	static int vidport;
	static int lines, cols;

	#ifdef CONFIG_KERNEL_GZIP
	#include "../../../../lib/decompress_inflate.c"
	#endif

	#ifdef CONFIG_KERNEL_BZIP2
	#include "../../../../lib/decompress_bunzip2.c"
	#endif

	#ifdef CONFIG_KERNEL_LZMA
	#include "../../../../lib/decompress_unlzma.c"
	#endif

	#ifdef CONFIG_KERNEL_XZ
	#include "../../../../lib/decompress_unxz.c"
	#endif

	#ifdef CONFIG_KERNEL_LZO
	#include "../../../../lib/decompress_unlzo.c"
	#endif

	#ifdef CONFIG_KERNEL_LZ4
	#include "../../../../lib/decompress_unlz4.c"
	#endif
	/*
	* NOTE: When adding a new decompressor, please update the analysis in
	* ../header.S.
	*/

	static void scroll(void)
	{
	int i;

	memmove(vidmem, vidmem + cols * 2, (lines - 1) * cols * 2);
	for (i = (lines - 1) * cols * 2; i < lines * cols * 2; i += 2)
	vidmem[i] = ' ';
	}

	#define XMTRDY 0x20

	#define TXR 0 /* Transmit register (WRITE) */
	#define LSR 5 /* Line Status */
	static void serial_putchar(int ch)
	{
	unsigned timeout = 0xffff;

	while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
	cpu_relax();

	outb(ch, early_serial_base + TXR);
	}

	void __putstr(const char *s)
	{
	int x, y, pos;
	char c;

	if (early_serial_base) {
	const char *str = s;
	while (*str) {
	if (*str == '\n')
	serial_putchar('\r');
	serial_putchar(*str++);
	}
	}

	if (lines == 0 \|\| cols == 0)
	return;

	x = boot_params->screen_info.orig_x;
	y = boot_params->screen_info.orig_y;

	while ((c = *s++) != '\0') {
	if (c == '\n') {
	x = 0;
	if (++y >= lines) {
	scroll();
	y--;
	}
	} else {
	vidmem[(x + cols * y) * 2] = c;
	if (++x >= cols) {
	x = 0;
	if (++y >= lines) {
	scroll();
	y--;
	}
	}
	}
	}

	boot_params->screen_info.orig_x = x;
	boot_params->screen_info.orig_y = y;

	pos = (x + cols * y) * 2; /* Update cursor position */
	outb(14, vidport);
	outb(0xff & (pos >> 9), vidport+1);
	outb(15, vidport);
	outb(0xff & (pos >> 1), vidport+1);
	}

	void __puthex(unsigned long value)
	{
	char alpha[2] = "0";
	int bits;

	for (bits = sizeof(value) * 8 - 4; bits >= 0; bits -= 4) {
	unsigned long digit = (value >> bits) & 0xf;

	if (digit < 0xA)
	alpha[0] = '0' + digit;
	else
	alpha[0] = 'a' + (digit - 0xA);

	__putstr(alpha);
	}
	}

	#if CONFIG_X86_NEED_RELOCS
	static void handle_relocations(void *output, unsigned long output_len,
	unsigned long virt_addr)
	{
	int *reloc;
	unsigned long delta, map, ptr;
	unsigned long min_addr = (unsigned long)output;
	unsigned long max_addr = min_addr + (VO___bss_start - VO__text);

	/*
	* Calculate the delta between where vmlinux was linked to load
	* and where it was actually loaded.
	*/
	delta = min_addr - LOAD_PHYSICAL_ADDR;

	/*
	* The kernel contains a table of relocation addresses. Those
	* addresses have the final load address of the kernel in virtual
	* memory. We are currently working in the self map. So we need to
	* create an adjustment for kernel memory addresses to the self map.
	* This will involve subtracting out the base address of the kernel.
	*/
	map = delta - __START_KERNEL_map;

	/*
	* 32-bit always performs relocations. 64-bit relocations are only
	* needed if KASLR has chosen a different starting address offset
	* from __START_KERNEL_map.
	*/
	if (IS_ENABLED(CONFIG_X86_64))
	delta = virt_addr - LOAD_PHYSICAL_ADDR;

	if (!delta) {
	debug_putstr("No relocation needed... ");
	return;
	}
	debug_putstr("Performing relocations... ");

	/*
	* Process relocations: 32 bit relocations first then 64 bit after.
	* Three sets of binary relocations are added to the end of the kernel
	* before compression. Each relocation table entry is the kernel
	* address of the location which needs to be updated stored as a
	* 32-bit value which is sign extended to 64 bits.
	*
	* Format is:
	*
	* kernel bits...
	* 0 - zero terminator for 64 bit relocations
	* 64 bit relocation repeated
	* 0 - zero terminator for inverse 32 bit relocations
	* 32 bit inverse relocation repeated
	* 0 - zero terminator for 32 bit relocations
	* 32 bit relocation repeated
	*
	* So we work backwards from the end of the decompressed image.
	*/
	for (reloc = output + output_len - sizeof(reloc); reloc; reloc--) {
	long extended = *reloc;
	extended += map;

	ptr = (unsigned long)extended;
	if (ptr < min_addr \|\| ptr > max_addr)
	error("32-bit relocation outside of kernel!\n");

	(uint32_t )ptr += delta;
	}
	#ifdef CONFIG_X86_64
	while (*--reloc) {
	long extended = *reloc;
	extended += map;

	ptr = (unsigned long)extended;
	if (ptr < min_addr \|\| ptr > max_addr)
	error("inverse 32-bit relocation outside of kernel!\n");

	(int32_t )ptr -= delta;
	}
	for (reloc--; *reloc; reloc--) {
	long extended = *reloc;
	extended += map;

	ptr = (unsigned long)extended;
	if (ptr < min_addr \|\| ptr > max_addr)
	error("64-bit relocation outside of kernel!\n");

	(uint64_t )ptr += delta;
	}
	#endif
	}
	#else
	static inline void handle_relocations(void *output, unsigned long output_len,
	unsigned long virt_addr)
	{ }
	#endif

	static void parse_elf(void *output)
	{
	#ifdef CONFIG_X86_64
	Elf64_Ehdr ehdr;
	Elf64_Phdr phdrs, phdr;
	#else
	Elf32_Ehdr ehdr;
	Elf32_Phdr phdrs, phdr;
	#endif
	void *dest;
	int i;

	memcpy(&ehdr, output, sizeof(ehdr));
	if (ehdr.e_ident[EI_MAG0] != ELFMAG0 \|\|
	ehdr.e_ident[EI_MAG1] != ELFMAG1 \|\|
	ehdr.e_ident[EI_MAG2] != ELFMAG2 \|\|
	ehdr.e_ident[EI_MAG3] != ELFMAG3) {
	error("Kernel is not a valid ELF file");
	return;
	}

	debug_putstr("Parsing ELF... ");

	phdrs = malloc(sizeof(phdrs) ehdr.e_phnum);
	if (!phdrs)
	error("Failed to allocate space for phdrs");

	memcpy(phdrs, output + ehdr.e_phoff, sizeof(phdrs) ehdr.e_phnum);

	for (i = 0; i < ehdr.e_phnum; i++) {
	phdr = &phdrs[i];

	switch (phdr->p_type) {
	case PT_LOAD:
	#ifdef CONFIG_X86_64
	if ((phdr->p_align % 0x200000) != 0)
	error("Alignment of LOAD segment isn't multiple of 2MB");
	#endif
	#ifdef CONFIG_RELOCATABLE
	dest = output;
	dest += (phdr->p_paddr - LOAD_PHYSICAL_ADDR);
	#else
	dest = (void *)(phdr->p_paddr);
	#endif
	memmove(dest, output + phdr->p_offset, phdr->p_filesz);
	break;
	default: /* Ignore other PT_* */ break;
	}
	}

	free(phdrs);
	}

	/*
	* The compressed kernel image (ZO), has been moved so that its position
	* is against the end of the buffer used to hold the uncompressed kernel
	* image (VO) and the execution environment (.bss, .brk), which makes sure
	* there is room to do the in-place decompression. (See header.S for the
	* calculations.)
	*
	* \|-----compressed kernel image------\|
	* V V
	* 0 extract_offset +INIT_SIZE
	* \|-----------\|---------------\|-------------------------\|--------\|
	* \| \| \| \|
	* VO__text startup_32 of ZO VO__end ZO__end
	* ^ ^
	* \|-------uncompressed kernel image---------\|
	*
	*/
	asmlinkage __visible void extract_kernel(void rmode, memptr heap,
	unsigned char *input_data,
	unsigned long input_len,
	unsigned char *output,
	unsigned long output_len)
	{
	const unsigned long kernel_total_size = VO__end - VO__text;
	unsigned long virt_addr = LOAD_PHYSICAL_ADDR;
	unsigned long needed_size;

	/* Retain x86 boot parameters pointer passed from startup_32/64. */
	boot_params = rmode;

	/* Clear flags intended for solely in-kernel use. */
	boot_params->hdr.loadflags &= ~KASLR_FLAG;

	sanitize_boot_params(boot_params);

	if (boot_params->screen_info.orig_video_mode == 7) {
	vidmem = (char *) 0xb0000;
	vidport = 0x3b4;
	} else {
	vidmem = (char *) 0xb8000;
	vidport = 0x3d4;
	}

	lines = boot_params->screen_info.orig_video_lines;
	cols = boot_params->screen_info.orig_video_cols;

	console_init();

	/*
	* Save RSDP address for later use. Have this after console_init()
	* so that early debugging output from the RSDP parsing code can be
	* collected.
	*/
	boot_params->acpi_rsdp_addr = get_rsdp_addr();

	debug_putstr("early console in extract_kernel\n");

	free_mem_ptr = heap; /* Heap */
	free_mem_end_ptr = heap + BOOT_HEAP_SIZE;

	/*
	* The memory hole needed for the kernel is the larger of either
	* the entire decompressed kernel plus relocation table, or the
	* entire decompressed kernel plus .bss and .brk sections.
	*
	* On X86_64, the memory is mapped with PMD pages. Round the
	* size up so that the full extent of PMD pages mapped is
	* included in the check against the valid memory table
	* entries. This ensures the full mapped area is usable RAM
	* and doesn't include any reserved areas.
	*/
	needed_size = max(output_len, kernel_total_size);
	#ifdef CONFIG_X86_64
	needed_size = ALIGN(needed_size, MIN_KERNEL_ALIGN);
	#endif

	/* Report initial kernel position details. */
	debug_putaddr(input_data);
	debug_putaddr(input_len);
	debug_putaddr(output);
	debug_putaddr(output_len);
	debug_putaddr(kernel_total_size);
	debug_putaddr(needed_size);

	#ifdef CONFIG_X86_64
	/* Report address of 32-bit trampoline */
	debug_putaddr(trampoline_32bit);
	#endif

	choose_random_location((unsigned long)input_data, input_len,
	(unsigned long *)&output,
	needed_size,
	&virt_addr);

	/* Validate memory location choices. */
	if ((unsigned long)output & (MIN_KERNEL_ALIGN - 1))
	error("Destination physical address inappropriately aligned");
	if (virt_addr & (MIN_KERNEL_ALIGN - 1))
	error("Destination virtual address inappropriately aligned");
	#ifdef CONFIG_X86_64
	if (heap > 0x3fffffffffffUL)
	error("Destination address too large");
	if (virt_addr + max(output_len, kernel_total_size) > KERNEL_IMAGE_SIZE)
	error("Destination virtual address is beyond the kernel mapping area");
	#else
	if (heap > ((-__PAGE_OFFSET-(128<<20)-1) & 0x7fffffff))
	error("Destination address too large");
	#endif
	#ifndef CONFIG_RELOCATABLE
	if ((unsigned long)output != LOAD_PHYSICAL_ADDR)
	error("Destination address does not match LOAD_PHYSICAL_ADDR");
	if (virt_addr != LOAD_PHYSICAL_ADDR)
	error("Destination virtual address changed when not relocatable");
	#endif

	debug_putstr("\nDecompressing Linux... ");
	__decompress(input_data, input_len, NULL, NULL, output, output_len,
	NULL, error);
	parse_elf(output);
	handle_relocations(output, output_len, virt_addr);
	debug_putstr("done.\nBooting the kernel.\n");
	return output;
	}

	void fortify_panic(const char *name)
	{
	error("detected buffer overflow");
	}