summaryrefslogtreecommitdiffstats
path: root/arch/x86/boot/compressed/misc.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/x86/boot/compressed/misc.c')
-rw-r--r--arch/x86/boot/compressed/misc.c472
1 files changed, 472 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..cf690d871
--- /dev/null
+++ b/arch/x86/boot/compressed/misc.c
@@ -0,0 +1,472 @@
+// 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
+/* Define an externally visible malloc()/free(). */
+#define MALLOC_VISIBLE
+#include <linux/decompress/mm.h>
+
+/*
+ * Provide definitions of memzero and memmove as some of the decompressors will
+ * try to define their own functions if these are not defined as macros.
+ */
+#define memzero(s, n) memset((s), 0, (n))
+#ifndef memmove
+#define memmove memmove
+/* Functions used by the included decompressor code below. */
+void *memmove(void *dest, const void *src, size_t n);
+#endif
+
+/*
+ * This is set up by the setup-routine at boot-time
+ */
+struct boot_params *boot_params;
+
+struct port_io_ops pio_ops;
+
+memptr free_mem_ptr;
+memptr free_mem_end_ptr;
+
+static char *vidmem;
+static int vidport;
+
+/* These might be accessed before .bss is cleared, so use .data instead. */
+static int lines __section(".data");
+static int cols __section(".data");
+
+#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
+
+#ifdef CONFIG_KERNEL_ZSTD
+#include "../../../../lib/decompress_unzstd.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);
+ }
+}
+
+#ifdef 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;
+
+ init_default_io_ops();
+
+ /*
+ * Detect TDX guest environment.
+ *
+ * It has to be done before console_init() in order to use
+ * paravirtualized port I/O operations if needed.
+ */
+ early_tdx_detect();
+
+ 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 (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");
+
+ /* Disable exception handling before booting the kernel */
+ cleanup_exception_handling();
+
+ return output;
+}
+
+void fortify_panic(const char *name)
+{
+ error("detected buffer overflow");
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-15 12:35:50 +0000