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Diffstat (limited to 'arch/x86/boot/compressed/misc.c')
| -rw-r--r-- | arch/x86/boot/compressed/misc.c | 437 |
1 files changed, 437 insertions, 0 deletions
diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c new file mode 100644 index 000000000..a107b935e --- /dev/null +++ b/arch/x86/boot/compressed/misc.c @@ -0,0 +1,437 @@ +/* + * 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; +} |