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458 lines
12 KiB
458 lines
12 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* misc.c |
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* |
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* This is a collection of several routines used to extract the kernel |
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* which includes KASLR relocation, decompression, ELF parsing, and |
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* relocation processing. Additionally included are the screen and serial |
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* output functions and related debugging support functions. |
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* |
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* malloc by Hannu Savolainen 1993 and Matthias Urlichs 1994 |
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* puts by Nick Holloway 1993, better puts by Martin Mares 1995 |
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* High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996 |
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*/ |
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#include "misc.h" |
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#include "error.h" |
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#include "pgtable.h" |
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#include "../string.h" |
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#include "../voffset.h" |
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#include <asm/bootparam_utils.h> |
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/* |
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* WARNING!! |
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* This code is compiled with -fPIC and it is relocated dynamically at |
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* run time, but no relocation processing is performed. This means that |
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* it is not safe to place pointers in static structures. |
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*/ |
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/* Macros used by the included decompressor code below. */ |
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#define STATIC static |
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/* |
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* Provide definitions of memzero and memmove as some of the decompressors will |
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* try to define their own functions if these are not defined as macros. |
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*/ |
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#define memzero(s, n) memset((s), 0, (n)) |
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#define memmove memmove |
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/* Functions used by the included decompressor code below. */ |
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void *memmove(void *dest, const void *src, size_t n); |
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/* |
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* This is set up by the setup-routine at boot-time |
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*/ |
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struct boot_params *boot_params; |
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memptr free_mem_ptr; |
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memptr free_mem_end_ptr; |
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static char *vidmem; |
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static int vidport; |
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static int lines, cols; |
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#ifdef CONFIG_KERNEL_GZIP |
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#include "../../../../lib/decompress_inflate.c" |
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#endif |
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#ifdef CONFIG_KERNEL_BZIP2 |
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#include "../../../../lib/decompress_bunzip2.c" |
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#endif |
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#ifdef CONFIG_KERNEL_LZMA |
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#include "../../../../lib/decompress_unlzma.c" |
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#endif |
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#ifdef CONFIG_KERNEL_XZ |
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#include "../../../../lib/decompress_unxz.c" |
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#endif |
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#ifdef CONFIG_KERNEL_LZO |
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#include "../../../../lib/decompress_unlzo.c" |
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#endif |
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#ifdef CONFIG_KERNEL_LZ4 |
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#include "../../../../lib/decompress_unlz4.c" |
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#endif |
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#ifdef CONFIG_KERNEL_ZSTD |
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#include "../../../../lib/decompress_unzstd.c" |
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#endif |
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/* |
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* NOTE: When adding a new decompressor, please update the analysis in |
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* ../header.S. |
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*/ |
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static void scroll(void) |
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{ |
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int i; |
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memmove(vidmem, vidmem + cols * 2, (lines - 1) * cols * 2); |
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for (i = (lines - 1) * cols * 2; i < lines * cols * 2; i += 2) |
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vidmem[i] = ' '; |
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} |
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#define XMTRDY 0x20 |
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#define TXR 0 /* Transmit register (WRITE) */ |
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#define LSR 5 /* Line Status */ |
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static void serial_putchar(int ch) |
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{ |
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unsigned timeout = 0xffff; |
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while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout) |
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cpu_relax(); |
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outb(ch, early_serial_base + TXR); |
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} |
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void __putstr(const char *s) |
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{ |
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int x, y, pos; |
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char c; |
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if (early_serial_base) { |
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const char *str = s; |
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while (*str) { |
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if (*str == '\n') |
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serial_putchar('\r'); |
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serial_putchar(*str++); |
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} |
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} |
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if (lines == 0 || cols == 0) |
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return; |
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x = boot_params->screen_info.orig_x; |
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y = boot_params->screen_info.orig_y; |
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while ((c = *s++) != '\0') { |
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if (c == '\n') { |
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x = 0; |
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if (++y >= lines) { |
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scroll(); |
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y--; |
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} |
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} else { |
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vidmem[(x + cols * y) * 2] = c; |
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if (++x >= cols) { |
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x = 0; |
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if (++y >= lines) { |
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scroll(); |
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y--; |
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} |
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} |
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} |
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} |
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boot_params->screen_info.orig_x = x; |
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boot_params->screen_info.orig_y = y; |
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pos = (x + cols * y) * 2; /* Update cursor position */ |
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outb(14, vidport); |
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outb(0xff & (pos >> 9), vidport+1); |
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outb(15, vidport); |
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outb(0xff & (pos >> 1), vidport+1); |
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} |
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void __puthex(unsigned long value) |
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{ |
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char alpha[2] = "0"; |
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int bits; |
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for (bits = sizeof(value) * 8 - 4; bits >= 0; bits -= 4) { |
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unsigned long digit = (value >> bits) & 0xf; |
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if (digit < 0xA) |
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alpha[0] = '0' + digit; |
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else |
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alpha[0] = 'a' + (digit - 0xA); |
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__putstr(alpha); |
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} |
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} |
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#if CONFIG_X86_NEED_RELOCS |
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static void handle_relocations(void *output, unsigned long output_len, |
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unsigned long virt_addr) |
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{ |
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int *reloc; |
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unsigned long delta, map, ptr; |
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unsigned long min_addr = (unsigned long)output; |
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unsigned long max_addr = min_addr + (VO___bss_start - VO__text); |
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/* |
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* Calculate the delta between where vmlinux was linked to load |
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* and where it was actually loaded. |
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*/ |
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delta = min_addr - LOAD_PHYSICAL_ADDR; |
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/* |
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* The kernel contains a table of relocation addresses. Those |
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* addresses have the final load address of the kernel in virtual |
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* memory. We are currently working in the self map. So we need to |
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* create an adjustment for kernel memory addresses to the self map. |
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* This will involve subtracting out the base address of the kernel. |
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*/ |
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map = delta - __START_KERNEL_map; |
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/* |
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* 32-bit always performs relocations. 64-bit relocations are only |
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* needed if KASLR has chosen a different starting address offset |
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* from __START_KERNEL_map. |
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*/ |
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if (IS_ENABLED(CONFIG_X86_64)) |
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delta = virt_addr - LOAD_PHYSICAL_ADDR; |
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if (!delta) { |
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debug_putstr("No relocation needed... "); |
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return; |
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} |
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debug_putstr("Performing relocations... "); |
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/* |
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* Process relocations: 32 bit relocations first then 64 bit after. |
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* Three sets of binary relocations are added to the end of the kernel |
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* before compression. Each relocation table entry is the kernel |
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* address of the location which needs to be updated stored as a |
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* 32-bit value which is sign extended to 64 bits. |
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* |
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* Format is: |
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* |
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* kernel bits... |
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* 0 - zero terminator for 64 bit relocations |
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* 64 bit relocation repeated |
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* 0 - zero terminator for inverse 32 bit relocations |
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* 32 bit inverse relocation repeated |
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* 0 - zero terminator for 32 bit relocations |
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* 32 bit relocation repeated |
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* |
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* So we work backwards from the end of the decompressed image. |
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*/ |
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for (reloc = output + output_len - sizeof(*reloc); *reloc; reloc--) { |
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long extended = *reloc; |
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extended += map; |
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ptr = (unsigned long)extended; |
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if (ptr < min_addr || ptr > max_addr) |
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error("32-bit relocation outside of kernel!\n"); |
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*(uint32_t *)ptr += delta; |
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} |
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#ifdef CONFIG_X86_64 |
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while (*--reloc) { |
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long extended = *reloc; |
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extended += map; |
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ptr = (unsigned long)extended; |
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if (ptr < min_addr || ptr > max_addr) |
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error("inverse 32-bit relocation outside of kernel!\n"); |
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*(int32_t *)ptr -= delta; |
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} |
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for (reloc--; *reloc; reloc--) { |
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long extended = *reloc; |
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extended += map; |
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ptr = (unsigned long)extended; |
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if (ptr < min_addr || ptr > max_addr) |
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error("64-bit relocation outside of kernel!\n"); |
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*(uint64_t *)ptr += delta; |
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} |
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#endif |
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} |
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#else |
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static inline void handle_relocations(void *output, unsigned long output_len, |
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unsigned long virt_addr) |
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{ } |
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#endif |
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static void parse_elf(void *output) |
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{ |
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#ifdef CONFIG_X86_64 |
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Elf64_Ehdr ehdr; |
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Elf64_Phdr *phdrs, *phdr; |
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#else |
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Elf32_Ehdr ehdr; |
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Elf32_Phdr *phdrs, *phdr; |
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#endif |
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void *dest; |
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int i; |
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memcpy(&ehdr, output, sizeof(ehdr)); |
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if (ehdr.e_ident[EI_MAG0] != ELFMAG0 || |
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ehdr.e_ident[EI_MAG1] != ELFMAG1 || |
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ehdr.e_ident[EI_MAG2] != ELFMAG2 || |
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ehdr.e_ident[EI_MAG3] != ELFMAG3) { |
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error("Kernel is not a valid ELF file"); |
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return; |
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} |
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debug_putstr("Parsing ELF... "); |
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phdrs = malloc(sizeof(*phdrs) * ehdr.e_phnum); |
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if (!phdrs) |
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error("Failed to allocate space for phdrs"); |
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memcpy(phdrs, output + ehdr.e_phoff, sizeof(*phdrs) * ehdr.e_phnum); |
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for (i = 0; i < ehdr.e_phnum; i++) { |
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phdr = &phdrs[i]; |
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switch (phdr->p_type) { |
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case PT_LOAD: |
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#ifdef CONFIG_X86_64 |
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if ((phdr->p_align % 0x200000) != 0) |
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error("Alignment of LOAD segment isn't multiple of 2MB"); |
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#endif |
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#ifdef CONFIG_RELOCATABLE |
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dest = output; |
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dest += (phdr->p_paddr - LOAD_PHYSICAL_ADDR); |
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#else |
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dest = (void *)(phdr->p_paddr); |
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#endif |
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memmove(dest, output + phdr->p_offset, phdr->p_filesz); |
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break; |
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default: /* Ignore other PT_* */ break; |
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} |
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} |
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free(phdrs); |
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} |
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/* |
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* The compressed kernel image (ZO), has been moved so that its position |
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* is against the end of the buffer used to hold the uncompressed kernel |
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* image (VO) and the execution environment (.bss, .brk), which makes sure |
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* there is room to do the in-place decompression. (See header.S for the |
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* calculations.) |
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* |
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* |-----compressed kernel image------| |
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* V V |
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* 0 extract_offset +INIT_SIZE |
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* |-----------|---------------|-------------------------|--------| |
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* | | | | |
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* VO__text startup_32 of ZO VO__end ZO__end |
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* ^ ^ |
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* |-------uncompressed kernel image---------| |
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* |
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*/ |
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asmlinkage __visible void *extract_kernel(void *rmode, memptr heap, |
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unsigned char *input_data, |
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unsigned long input_len, |
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unsigned char *output, |
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unsigned long output_len) |
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{ |
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const unsigned long kernel_total_size = VO__end - VO__text; |
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unsigned long virt_addr = LOAD_PHYSICAL_ADDR; |
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unsigned long needed_size; |
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/* Retain x86 boot parameters pointer passed from startup_32/64. */ |
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boot_params = rmode; |
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/* Clear flags intended for solely in-kernel use. */ |
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boot_params->hdr.loadflags &= ~KASLR_FLAG; |
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sanitize_boot_params(boot_params); |
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if (boot_params->screen_info.orig_video_mode == 7) { |
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vidmem = (char *) 0xb0000; |
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vidport = 0x3b4; |
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} else { |
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vidmem = (char *) 0xb8000; |
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vidport = 0x3d4; |
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} |
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lines = boot_params->screen_info.orig_video_lines; |
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cols = boot_params->screen_info.orig_video_cols; |
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console_init(); |
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/* |
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* Save RSDP address for later use. Have this after console_init() |
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* so that early debugging output from the RSDP parsing code can be |
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* collected. |
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*/ |
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boot_params->acpi_rsdp_addr = get_rsdp_addr(); |
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debug_putstr("early console in extract_kernel\n"); |
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free_mem_ptr = heap; /* Heap */ |
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free_mem_end_ptr = heap + BOOT_HEAP_SIZE; |
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/* |
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* The memory hole needed for the kernel is the larger of either |
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* the entire decompressed kernel plus relocation table, or the |
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* entire decompressed kernel plus .bss and .brk sections. |
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* |
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* On X86_64, the memory is mapped with PMD pages. Round the |
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* size up so that the full extent of PMD pages mapped is |
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* included in the check against the valid memory table |
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* entries. This ensures the full mapped area is usable RAM |
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* and doesn't include any reserved areas. |
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*/ |
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needed_size = max(output_len, kernel_total_size); |
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#ifdef CONFIG_X86_64 |
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needed_size = ALIGN(needed_size, MIN_KERNEL_ALIGN); |
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#endif |
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/* Report initial kernel position details. */ |
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debug_putaddr(input_data); |
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debug_putaddr(input_len); |
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debug_putaddr(output); |
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debug_putaddr(output_len); |
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debug_putaddr(kernel_total_size); |
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debug_putaddr(needed_size); |
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#ifdef CONFIG_X86_64 |
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/* Report address of 32-bit trampoline */ |
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debug_putaddr(trampoline_32bit); |
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#endif |
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choose_random_location((unsigned long)input_data, input_len, |
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(unsigned long *)&output, |
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needed_size, |
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&virt_addr); |
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/* Validate memory location choices. */ |
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if ((unsigned long)output & (MIN_KERNEL_ALIGN - 1)) |
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error("Destination physical address inappropriately aligned"); |
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if (virt_addr & (MIN_KERNEL_ALIGN - 1)) |
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error("Destination virtual address inappropriately aligned"); |
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#ifdef CONFIG_X86_64 |
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if (heap > 0x3fffffffffffUL) |
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error("Destination address too large"); |
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if (virt_addr + max(output_len, kernel_total_size) > KERNEL_IMAGE_SIZE) |
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error("Destination virtual address is beyond the kernel mapping area"); |
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#else |
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if (heap > ((-__PAGE_OFFSET-(128<<20)-1) & 0x7fffffff)) |
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error("Destination address too large"); |
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#endif |
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#ifndef CONFIG_RELOCATABLE |
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if ((unsigned long)output != LOAD_PHYSICAL_ADDR) |
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error("Destination address does not match LOAD_PHYSICAL_ADDR"); |
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if (virt_addr != LOAD_PHYSICAL_ADDR) |
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error("Destination virtual address changed when not relocatable"); |
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#endif |
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debug_putstr("\nDecompressing Linux... "); |
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__decompress(input_data, input_len, NULL, NULL, output, output_len, |
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NULL, error); |
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parse_elf(output); |
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handle_relocations(output, output_len, virt_addr); |
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debug_putstr("done.\nBooting the kernel.\n"); |
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/* |
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* Flush GHCB from cache and map it encrypted again when running as |
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* SEV-ES guest. |
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*/ |
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sev_es_shutdown_ghcb(); |
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return output; |
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} |
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void fortify_panic(const char *name) |
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{ |
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error("detected buffer overflow"); |
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}
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