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-rw-r--r--kernel/arch/x86/boot/compressed/misc.c437
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diff --git a/kernel/arch/x86/boot/compressed/misc.c b/kernel/arch/x86/boot/compressed/misc.c
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+/*
+ * misc.c
+ *
+ * This is a collection of several routines from gzip-1.0.3
+ * adapted for Linux.
+ *
+ * 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 "../string.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.
+ */
+
+/*
+ * Getting to provable safe in place decompression is hard.
+ * Worst case behaviours need to be analyzed.
+ * Background information:
+ *
+ * The file layout is:
+ * magic[2]
+ * method[1]
+ * flags[1]
+ * timestamp[4]
+ * extraflags[1]
+ * os[1]
+ * compressed data blocks[N]
+ * crc[4] orig_len[4]
+ *
+ * resulting in 18 bytes of non compressed data overhead.
+ *
+ * Files divided into blocks
+ * 1 bit (last block flag)
+ * 2 bits (block type)
+ *
+ * 1 block occurs every 32K -1 bytes or when there 50% compression
+ * has been achieved. The smallest block type encoding is always used.
+ *
+ * stored:
+ * 32 bits length in bytes.
+ *
+ * fixed:
+ * magic fixed tree.
+ * symbols.
+ *
+ * dynamic:
+ * dynamic tree encoding.
+ * symbols.
+ *
+ *
+ * The buffer for decompression in place is the length of the
+ * uncompressed data, plus a small amount extra to keep the algorithm safe.
+ * The compressed data is placed at the end of the buffer. The output
+ * pointer is placed at the start of the buffer and the input pointer
+ * is placed where the compressed data starts. Problems will occur
+ * when the output pointer overruns the input pointer.
+ *
+ * The output pointer can only overrun the input pointer if the input
+ * pointer is moving faster than the output pointer. A condition only
+ * triggered by data whose compressed form is larger than the uncompressed
+ * form.
+ *
+ * The worst case at the block level is a growth of the compressed data
+ * of 5 bytes per 32767 bytes.
+ *
+ * The worst case internal to a compressed block is very hard to figure.
+ * The worst case can at least be boundined by having one bit that represents
+ * 32764 bytes and then all of the rest of the bytes representing the very
+ * very last byte.
+ *
+ * All of which is enough to compute an amount of extra data that is required
+ * to be safe. To avoid problems at the block level allocating 5 extra bytes
+ * per 32767 bytes of data is sufficient. To avoind problems internal to a
+ * block adding an extra 32767 bytes (the worst case uncompressed block size)
+ * is sufficient, to ensure that in the worst case the decompressed data for
+ * block will stop the byte before the compressed data for a block begins.
+ * To avoid problems with the compressed data's meta information an extra 18
+ * bytes are needed. Leading to the formula:
+ *
+ * extra_bytes = (uncompressed_size >> 12) + 32768 + 18 + decompressor_size.
+ *
+ * Adding 8 bytes per 32K is a bit excessive but much easier to calculate.
+ * Adding 32768 instead of 32767 just makes for round numbers.
+ * Adding the decompressor_size is necessary as it musht live after all
+ * of the data as well. Last I measured the decompressor is about 14K.
+ * 10K of actual data and 4K of bss.
+ *
+ */
+
+/*
+ * gzip declarations
+ */
+#define STATIC static
+
+#undef memcpy
+
+/*
+ * Use a normal definition of memset() 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 memset
+#define memzero(s, n) memset((s), 0, (n))
+
+
+static void error(char *m);
+
+/*
+ * This is set up by the setup-routine at boot-time
+ */
+struct boot_params *real_mode; /* Pointer to real-mode data */
+
+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
+
+static void scroll(void)
+{
+ int i;
+
+ memcpy(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 (real_mode->screen_info.orig_video_mode == 0 &&
+ lines == 0 && cols == 0)
+ return;
+
+ x = real_mode->screen_info.orig_x;
+ y = real_mode->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--;
+ }
+ }
+ }
+ }
+
+ real_mode->screen_info.orig_x = x;
+ real_mode->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);
+}
+
+static void error(char *x)
+{
+ error_putstr("\n\n");
+ error_putstr(x);
+ error_putstr("\n\n -- System halted");
+
+ while (1)
+ asm("hlt");
+}
+
+#if CONFIG_X86_NEED_RELOCS
+static void handle_relocations(void *output, unsigned long output_len)
+{
+ int *reloc;
+ unsigned long delta, map, ptr;
+ unsigned long min_addr = (unsigned long)output;
+ unsigned long max_addr = min_addr + output_len;
+
+ /*
+ * Calculate the delta between where vmlinux was linked to load
+ * and where it was actually loaded.
+ */
+ delta = min_addr - LOAD_PHYSICAL_ADDR;
+ if (!delta) {
+ debug_putstr("No relocation needed... ");
+ return;
+ }
+ debug_putstr("Performing relocations... ");
+
+ /*
+ * 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;
+
+ /*
+ * 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--) {
+ int 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)
+{ }
+#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_RELOCATABLE
+ dest = output;
+ dest += (phdr->p_paddr - LOAD_PHYSICAL_ADDR);
+#else
+ dest = (void *)(phdr->p_paddr);
+#endif
+ memcpy(dest,
+ output + phdr->p_offset,
+ phdr->p_filesz);
+ break;
+ default: /* Ignore other PT_* */ break;
+ }
+ }
+
+ free(phdrs);
+}
+
+asmlinkage __visible void *decompress_kernel(void *rmode, memptr heap,
+ unsigned char *input_data,
+ unsigned long input_len,
+ unsigned char *output,
+ unsigned long output_len,
+ unsigned long run_size)
+{
+ unsigned char *output_orig = output;
+
+ real_mode = rmode;
+
+ /* Clear it for solely in-kernel use */
+ real_mode->hdr.loadflags &= ~KASLR_FLAG;
+
+ sanitize_boot_params(real_mode);
+
+ if (real_mode->screen_info.orig_video_mode == 7) {
+ vidmem = (char *) 0xb0000;
+ vidport = 0x3b4;
+ } else {
+ vidmem = (char *) 0xb8000;
+ vidport = 0x3d4;
+ }
+
+ lines = real_mode->screen_info.orig_video_lines;
+ cols = real_mode->screen_info.orig_video_cols;
+
+ console_init();
+ debug_putstr("early console in decompress_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.
+ */
+ output = choose_kernel_location(real_mode, input_data, input_len, output,
+ output_len > run_size ? output_len
+ : run_size);
+
+ /* Validate memory location choices. */
+ if ((unsigned long)output & (MIN_KERNEL_ALIGN - 1))
+ error("Destination 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("Wrong destination address");
+#endif
+
+ debug_putstr("\nDecompressing Linux... ");
+ decompress(input_data, input_len, NULL, NULL, output, NULL, error);
+ parse_elf(output);
+ /*
+ * 32-bit always performs relocations. 64-bit relocations are only
+ * needed if kASLR has chosen a different load address.
+ */
+ if (!IS_ENABLED(CONFIG_X86_64) || output != output_orig)
+ handle_relocations(output, output_len);
+ debug_putstr("done.\nBooting the kernel.\n");
+ return output;
+}