text: /*
   * 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 "../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 (boot_params->screen_info.orig_video_mode == 0 &&
  	    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;
  
  	/* 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();
  	debug_putstr("early console in extract_kernel\n");
  
  	free_mem_ptr     = heap;	/* Heap */
  	free_mem_end_ptr = heap + BOOT_HEAP_SIZE;
  
  	/* 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);
  
  	/*
  	 * 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.
  	 */
  	choose_random_location((unsigned long)input_data, input_len,
  				(unsigned long *)&output,
  				max(output_len, kernel_total_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");
  #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");
  }
  