+++ /dev/null
-/*
- * mboot.c
- *
- * Loader for Multiboot-compliant kernels and modules.
- *
- * Copyright (C) 2005 Tim Deegan <Tim.Deegan@cl.cam.ac.uk>
- * Parts based on GNU GRUB, Copyright (C) 2000 Free Software Foundation, Inc.
- * Parts based on SYSLINUX, Copyright (C) 1994-2005 H. Peter Anvin.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
- * 02111-1307, USA.
- *
- */
-
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <stddef.h>
-#include <string.h>
-#include <malloc.h>
-#include <consoles.h>
-#include <zlib.h>
-#include <com32.h>
-
-#include "i386-elf.h"
-#include "mb_info.h"
-#include "mb_header.h"
-
-#include <klibc/compiler.h> /* For __constructor */
-
-#define MIN(_x, _y) (((_x)<(_y))?(_x):(_y))
-#define MAX(_x, _y) (((_x)>(_y))?(_x):(_y))
-
-/* Define this for some more printout */
-#undef DEBUG
-
-/* Memory magic numbers */
-#define STACK_SIZE 0x20000 /* XXX Could be much smaller */
-#define MALLOC_SIZE 0x100000 /* XXX Could be much smaller */
-#define MIN_RUN_ADDR 0x10000 /* Lowest address we'll consider using */
-#define MEM_HOLE_START 0xa0000 /* Memory hole runs from 640k ... */
-#define MEM_HOLE_END 0x100000 /* ... to 1MB */
-#define X86_PAGE_SIZE 0x1000
-
-size_t __stack_size = STACK_SIZE; /* How much stack we'll use */
-extern void *__mem_end; /* Start of malloc() heap */
-extern char _end[]; /* End of static data */
-
-/* Pointer to free memory for loading into: load area is between here
- * and section_addr */
-static char *next_load_addr;
-
-/* Memory map for run-time */
-typedef struct section section_t;
-struct section {
- size_t dest; /* Start of run-time allocation */
- char *src; /* Current location of data for memmove(),
- * or NULL for bzero() */
- size_t size; /* Length of allocation */
-};
-static char *section_addr;
-static int section_count;
-
-static size_t max_run_addr; /* Highest address we'll consider using */
-static size_t next_mod_run_addr; /* Where the next module will be put */
-
-/* File loads are in units of this much */
-#define LOAD_CHUNK 0x20000
-
-/* Layout of the input to the 32-bit lidt instruction */
-struct lidt_operand {
- unsigned int limit:16;
- unsigned int base:32;
-} __attribute__((packed));
-
-/* Magic strings */
-static const char version_string[] = "COM32 Multiboot loader v0.1";
-static const char copyright_string[] = "Copyright (C) 2005 Tim Deegan.";
-static const char module_separator[] = "---";
-
-
-/*
- * Start of day magic, run from __start during library init.
- */
-
-static void __constructor check_version(void)
- /* Check the SYSLINUX version. Docs say we should be OK from v2.08,
- * but in fact we crash on anything below v2.12 (when libc came in). */
-{
- com32sys_t regs_in, regs_out;
- const char *p, *too_old = "Fatal: SYSLINUX image is too old; "
- "mboot.c32 needs at least version 2.12.\r\n";
-
- memset(®s_in, 0, sizeof(regs_in));
- regs_in.eax.l = 0x0001; /* "Get version" */
- __intcall(0x22, ®s_in, ®s_out);
- if (regs_out.ecx.w[0] >= 0x020c) return;
-
- /* Pointless: on older versions this print fails too. :( */
- for (p = too_old ; *p ; p++) {
- memset(®s_in, 0, sizeof(regs_in));
- regs_in.eax.b[1] = 0x02; /* "Write character" */
- regs_in.edx.b[0] = *p;
- __intcall(0x21, ®s_in, ®s_out);
- }
-
- __intcall(0x20, ®s_in, ®s_out); /* "Terminate program" */
-}
-
-
-static void __constructor grab_memory(void)
- /* Runs before init_memory_arena() (com32/lib/malloc.c) to let
- * the malloc() code know how much space it's allowed to use.
- * We don't use malloc() directly, but some of the library code
- * does (zlib, for example). */
-{
- /* Find the stack pointer */
- register char * sp;
- asm volatile("movl %%esp, %0" : "=r" (sp));
-
- /* Initialize the allocation of *run-time* memory: don't let ourselves
- * overwrite the stack during the relocation later. */
- max_run_addr = (size_t) sp - (MALLOC_SIZE + STACK_SIZE);
-
- /* Move the end-of-memory marker: malloc() will use only memory
- * above __mem_end and below the stack. We will load files starting
- * at the old __mem_end and working towards the new one, and allocate
- * section descriptors at the top of that area, working down. */
- next_load_addr = __mem_end;
- section_addr = sp - (MALLOC_SIZE + STACK_SIZE);
- section_count = 0;
-
- /* But be careful not to move it the wrong direction if memory is
- * tight. Instead we'll fail more gracefully later, when we try to
- * load a file and find that next_load_addr > section_addr. */
- __mem_end = MAX(section_addr, next_load_addr);
-}
-
-
-
-
-/*
- * Run-time memory map functions: allocating and recording allocations.
- */
-
-static int cmp_sections(const void *a, const void *b)
- /* For sorting section descriptors by destination address */
-{
- const section_t *sa = a;
- const section_t *sb = b;
- if (sa->dest < sb->dest) return -1;
- if (sa->dest > sb->dest) return 1;
- return 0;
-}
-
-
-static void add_section(size_t dest, char *src, size_t size)
- /* Adds something to the list of sections to relocate. */
-{
- section_t *sec;
-
-#ifdef DEBUG
- printf("SECTION: %#8.8x --> %#8.8x (%#x)\n", (size_t) src, dest, size);
-#endif
-
- section_addr -= sizeof (section_t);
- if (section_addr < next_load_addr) {
- printf("Fatal: out of memory allocating section descriptor.\n");
- exit(1);
- }
- sec = (section_t *) section_addr;
- section_count++;
-
- sec->src = src;
- sec->dest = dest;
- sec->size = size;
-
- /* Keep the list sorted */
- qsort(sec, section_count, sizeof (section_t), cmp_sections);
-}
-
-
-static size_t place_low_section(size_t size, size_t align)
- /* Find a space in the run-time memory map, below 640K */
-{
- int i;
- size_t start;
- section_t *sections = (section_t *) section_addr;
-
- start = MIN_RUN_ADDR;
- start = (start + (align-1)) & ~(align-1);
-
- /* Section list is sorted by destination, so can do this in one pass */
- for (i = 0; i < section_count; i++) {
- if (sections[i].dest < start + size) {
- /* Hit the bottom of this section */
- start = sections[i].dest + sections[i].size;
- start = (start + (align-1)) & ~(align-1);
- }
- }
- if (start + size < MEM_HOLE_START) return start;
- else return 0;
-}
-
-
-static size_t place_module_section(size_t size, size_t align)
- /* Find a space in the run-time memory map for this module. */
-{
- /* Ideally we'd run through the sections looking for a free space
- * like place_low_section() does, but some OSes (Xen, at least)
- * assume that the bootloader has loaded all the modules
- * consecutively, above the kernel. So, what we actually do is
- * keep a pointer to the highest address allocated so far, and
- * always allocate modules there. */
-
- size_t start = next_mod_run_addr;
- start = (start + (align-1)) & ~(align-1);
-
- if (start + size > max_run_addr) return 0;
-
- next_mod_run_addr = start + size;
- return start;
-}
-
-
-static void place_kernel_section(size_t start, size_t size)
- /* Allocate run-time space for part of the kernel, checking for
- * sanity. We assume the kernel isn't broken enough to have
- * overlapping segments. */
-{
- /* We always place modules above the kernel */
- next_mod_run_addr = MAX(next_mod_run_addr, start + size);
-
- if (start > max_run_addr || start + size > max_run_addr) {
- /* Overruns the end of memory */
- printf("Fatal: kernel loads too high (%#8.8x+%#x > %#8.8x).\n",
- start, size, max_run_addr);
- exit(1);
- }
- if (start >= MEM_HOLE_END) {
- /* Above the memory hole: easy */
-#ifdef DEBUG
- printf("Placed kernel section (%#8.8x+%#x)\n", start, size);
-#endif
- return;
- }
- if (start >= MEM_HOLE_START) {
- /* In the memory hole. Not so good */
- printf("Fatal: kernel load address (%#8.8x) is in the memory hole.\n",
- start);
- exit(1);
- }
- if (start + size > MEM_HOLE_START) {
- /* Too big for low memory */
- printf("Fatal: kernel (%#8.8x+%#x) runs into the memory hole.\n",
- start, size);
- exit(1);
- }
- if (start < MIN_RUN_ADDR) {
- /* Loads too low */
- printf("Fatal: kernel load address (%#8.8x) is too low (<%#8.8x).\n",
- start, MIN_RUN_ADDR);
- exit(1);
- }
- /* Kernel loads below the memory hole: OK */
-#ifdef DEBUG
- printf("Placed kernel section (%#8.8x+%#x)\n", start, size);
-#endif
-}
-
-
-static void reorder_sections(void)
- /* Reorders sections into a safe order, where no relocation
- * overwrites the source of a later one. */
-{
- section_t *secs = (section_t *) section_addr;
- section_t tmp;
- int i, j, tries;
-
-#ifdef DEBUG
- printf("Relocations:\n");
- for (i = 0; i < section_count ; i++) {
- printf(" %#8.8x --> %#8.8x (%#x)\n",
- (size_t)secs[i].src, secs[i].dest, secs[i].size);
- }
-#endif
-
- for (i = 0; i < section_count; i++) {
- tries = 0;
- scan_again:
- for (j = i + 1 ; j < section_count; j++) {
- if (secs[j].src != NULL
- && secs[i].dest + secs[i].size > (size_t) secs[j].src
- && secs[i].dest < (size_t) secs[j].src + secs[j].size) {
- /* Would overwrite the source of the later move */
- if (++tries > section_count) {
- /* Deadlock! */
- /* XXX Try to break deadlocks? */
- printf("Fatal: circular dependence in relocations.\n");
- exit(1);
- }
- /* Swap these sections (using struct copies) */
- tmp = secs[i]; secs[i] = secs[j]; secs[j] = tmp;
- /* Start scanning again from the new secs[i]... */
- goto scan_again;
- }
- }
- }
-
-#ifdef DEBUG
- printf("Relocations:\n");
- for (i = 0; i < section_count ; i++) {
- printf(" %#8.8x --> %#8.8x (%#x)\n",
- (size_t)secs[i].src, secs[i].dest, secs[i].size);
- }
-#endif
-}
-
-
-static void init_mmap(struct multiboot_info *mbi)
- /* Get a full memory map from the BIOS to pass to the kernel. */
-{
- com32sys_t regs_in, regs_out;
- struct AddrRangeDesc *e820;
- int e820_slots;
- size_t mem_lower, mem_upper, run_addr, mmap_size;
- register size_t sp;
-
- /* Default values for mem_lower and mem_upper in case the BIOS won't
- * tell us: 640K, and all memory up to the stack. */
- asm volatile("movl %%esp, %0" : "=r" (sp));
- mem_upper = (sp - MEM_HOLE_END) / 1024;
- mem_lower = (MEM_HOLE_START) / 1024;
-
-#ifdef DEBUG
- printf("Requesting memory map from BIOS:\n");
-#endif
-
- /* Ask the BIOS for the full memory map of the machine. We'll
- * build it in Multiboot format (i.e. with size fields) in the
- * bounce buffer, and then allocate some high memory to keep it in
- * until boot time. */
- e820 = __com32.cs_bounce;
- e820_slots = 0;
- regs_out.ebx.l = 0;
-
- while(((void *)(e820 + 1)) < __com32.cs_bounce + __com32.cs_bounce_size)
- {
-
- e820->size = sizeof(*e820) - sizeof(e820->size);
-
- /* Ask the BIOS to fill in this descriptor */
- regs_in.eax.l = 0xe820; /* "Get system memory map" */
- regs_in.ebx.l = regs_out.ebx.l; /* Continuation value from last call */
- regs_in.ecx.l = 20; /* Size of buffer to write into */
- regs_in.edx.l = 0x534d4150; /* "SMAP" */
- regs_in.es = SEG(&e820->BaseAddr);
- regs_in.edi.w[0] = OFFS(&e820->BaseAddr);
- __intcall(0x15, ®s_in, ®s_out);
-
- if ((regs_out.eflags.l & EFLAGS_CF) != 0 && regs_out.ebx.l != 0)
- break; /* End of map */
-
- if (((regs_out.eflags.l & EFLAGS_CF) != 0 && regs_out.ebx.l == 0)
- || (regs_out.eax.l != 0x534d4150))
- {
- /* Error */
- printf("Error %x reading E820 memory map: %s.\n",
- (int) regs_out.eax.b[0],
- (regs_out.eax.b[0] == 0x80) ? "invalid command" :
- (regs_out.eax.b[0] == 0x86) ? "not supported" :
- "unknown error");
- break;
- }
-
- /* Success */
-#ifdef DEBUG
- printf(" %#16.16Lx -- %#16.16Lx : ",
- e820->BaseAddr, e820->BaseAddr + e820->Length);
- switch (e820->Type) {
- case 1: printf("Available\n"); break;
- case 2: printf("Reserved\n"); break;
- case 3: printf("ACPI Reclaim\n"); break;
- case 4: printf("ACPI NVS\n"); break;
- default: printf("? (Reserved)\n"); break;
- }
-#endif
-
- if (e820->Type == 1) {
- if (e820->BaseAddr == 0) {
- mem_lower = MIN(MEM_HOLE_START, e820->Length) / 1024;
- } else if (e820->BaseAddr == MEM_HOLE_END) {
- mem_upper = MIN(0xfff00000, e820->Length) / 1024;
- }
- }
-
- /* Move to next slot */
- e820++;
- e820_slots++;
-
- /* Done? */
- if (regs_out.ebx.l == 0)
- break;
- }
-
- /* Record the simple information in the MBI */
- mbi->flags |= MB_INFO_MEMORY;
- mbi->mem_lower = mem_lower;
- mbi->mem_upper = mem_upper;
-
- /* Record the full memory map in the MBI */
- if (e820_slots != 0) {
- mmap_size = e820_slots * sizeof(*e820);
- /* Where will it live at run time? */
- run_addr = place_low_section(mmap_size, 1);
- if (run_addr == 0) {
- printf("Fatal: can't find space for the e820 mmap.\n");
- exit(1);
- }
- /* Where will it live now? */
- e820 = (struct AddrRangeDesc *) next_load_addr;
- if (next_load_addr + mmap_size > section_addr) {
- printf("Fatal: out of memory storing the e820 mmap.\n");
- exit(1);
- }
- next_load_addr += mmap_size;
- /* Copy it out of the bounce buffer */
- memcpy(e820, __com32.cs_bounce, mmap_size);
- /* Remember to copy it again at run time */
- add_section(run_addr, (char *) e820, mmap_size);
- /* Record it in the MBI */
- mbi->flags |= MB_INFO_MEM_MAP;
- mbi->mmap_length = mmap_size;
- mbi->mmap_addr = run_addr;
- }
-}
-
-
-
-
-/*
- * Code for loading and parsing files.
- */
-
-static void load_file(char *filename, char **startp, size_t *sizep)
- /* Load a file into memory. Returns where it is and how big via
- * startp and sizep */
-{
- gzFile fp;
- char *start;
- int bsize;
-
- printf("Loading %s.", filename);
-
- start = next_load_addr;
- startp[0] = start;
- sizep[0] = 0;
-
- /* Open the file */
- if ((fp = gzopen(filename, "r")) == NULL) {
- printf("\nFatal: cannot open %s\n", filename);
- exit(1);
- }
-
- while (next_load_addr + LOAD_CHUNK <= section_addr) {
- bsize = gzread(fp, next_load_addr, LOAD_CHUNK);
- printf("%s",".");
-
- if (bsize < 0) {
- printf("\nFatal: read error in %s\n", filename);
- gzclose(fp);
- exit(1);
- }
-
- next_load_addr += bsize;
- sizep[0] += bsize;
-
- if (bsize < LOAD_CHUNK) {
- printf("%s","\n");
- gzclose(fp);
- return;
- }
- }
-
- /* Running out of memory. Try and use up the last bit */
- if (section_addr > next_load_addr) {
- bsize = gzread(fp, next_load_addr, section_addr - next_load_addr);
- printf("%s",".");
- } else {
- bsize = 0;
- }
-
- if (bsize < 0) {
- gzclose(fp);
- printf("\nFatal: read error in %s\n", filename);
- exit(1);
- }
-
- next_load_addr += bsize;
- sizep[0] += bsize;
-
- if (!gzeof(fp)) {
- gzclose(fp);
- printf("\nFatal: out of memory reading %s\n", filename);
- exit(1);
- }
-
- printf("%s","\n");
- gzclose(fp);
- return;
-}
-
-
-static size_t load_kernel(char *cmdline)
- /* Load a multiboot/elf32 kernel and allocate run-time memory for it.
- * Returns the kernel's entry address. */
-{
- unsigned int i;
- char *load_addr; /* Where the image was loaded */
- size_t load_size; /* How big it is */
- char *seg_addr; /* Where a segment was loaded */
- size_t seg_size, bss_size; /* How big it is */
- size_t run_addr, run_size; /* Where it should be put */
- char *p;
- Elf32_Ehdr *ehdr;
- Elf32_Phdr *phdr;
- struct multiboot_header *mbh;
-
- printf("Kernel: %s\n", cmdline);
-
- load_addr = 0;
- load_size = 0;
- p = strchr(cmdline, ' ');
- if (p != NULL) *p = 0;
- load_file(cmdline, &load_addr, &load_size);
- if (load_size < 12) {
- printf("Fatal: %s is too short to be a multiboot kernel.",
- cmdline);
- exit(1);
- }
- if (p != NULL) *p = ' ';
-
-
- /* Look for a multiboot header in the first 8k of the file */
- for (i = 0; i <= MIN(load_size - 12, MULTIBOOT_SEARCH - 12); i += 4)
- {
- mbh = (struct multiboot_header *)(load_addr + i);
- if (mbh->magic != MULTIBOOT_MAGIC
- || ((mbh->magic+mbh->flags+mbh->checksum) & 0xffffffff))
- {
- /* Not a multiboot header */
- continue;
- }
- if (mbh->flags & (MULTIBOOT_UNSUPPORTED | MULTIBOOT_VIDEO_MODE)) {
- /* Requires options we don't support */
- printf("Fatal: Kernel requires multiboot options "
- "that I don't support: %#x.\n",
- mbh->flags & (MULTIBOOT_UNSUPPORTED|MULTIBOOT_VIDEO_MODE));
- exit(1);
- }
-
- /* This kernel will do: figure out where all the pieces will live */
-
- if (mbh->flags & MULTIBOOT_AOUT_KLUDGE) {
-
- /* Use the offsets in the multiboot header */
-#ifdef DEBUG
- printf("Using multiboot header.\n");
-#endif
-
- /* Where is the code in the loaded file? */
- seg_addr = ((char *)mbh) - (mbh->header_addr - mbh->load_addr);
-
- /* How much code is there? */
- run_addr = mbh->load_addr;
- if (mbh->load_end_addr != 0)
- seg_size = mbh->load_end_addr - mbh->load_addr;
- else
- seg_size = load_size - (seg_addr - load_addr);
-
- /* How much memory will it take up? */
- if (mbh->bss_end_addr != 0)
- run_size = mbh->bss_end_addr - mbh->load_addr;
- else
- run_size = seg_size;
-
- if (seg_size > run_size) {
- printf("Fatal: can't put %i bytes of kernel into %i bytes "
- "of memory.\n", seg_size, run_size);
- exit(1);
- }
- if (seg_addr + seg_size > load_addr + load_size) {
- printf("Fatal: multiboot load segment runs off the "
- "end of the file.\n");
- exit(1);
- }
-
- /* Does it fit where it wants to be? */
- place_kernel_section(run_addr, run_size);
-
- /* Put it on the relocation list */
- if (seg_size < run_size) {
- /* Set up the kernel BSS too */
- if (seg_size > 0)
- add_section(run_addr, seg_addr, seg_size);
- bss_size = run_size - seg_size;
- add_section(run_addr + seg_size, NULL, bss_size);
- } else {
- /* No BSS */
- add_section(run_addr, seg_addr, run_size);
- }
-
- /* Done. */
- return mbh->entry_addr;
-
- } else {
-
- /* Now look for an ELF32 header */
- ehdr = (Elf32_Ehdr *)load_addr;
- if (*(unsigned long *)ehdr != 0x464c457f
- || ehdr->e_ident[EI_DATA] != ELFDATA2LSB
- || ehdr->e_ident[EI_CLASS] != ELFCLASS32
- || ehdr->e_machine != EM_386)
- {
- printf("Fatal: kernel has neither ELF32/x86 nor multiboot load"
- " headers.\n");
- exit(1);
- }
- if (ehdr->e_phoff + ehdr->e_phnum*sizeof (*phdr) > load_size) {
- printf("Fatal: malformed ELF header overruns EOF.\n");
- exit(1);
- }
- if (ehdr->e_phnum <= 0) {
- printf("Fatal: ELF kernel has no program headers.\n");
- exit(1);
- }
-
-#ifdef DEBUG
- printf("Using ELF header.\n");
-#endif
-
- if (ehdr->e_type != ET_EXEC
- || ehdr->e_version != EV_CURRENT
- || ehdr->e_phentsize != sizeof (Elf32_Phdr)) {
- printf("Warning: funny-looking ELF header.\n");
- }
- phdr = (Elf32_Phdr *)(load_addr + ehdr->e_phoff);
-
- /* Obey the program headers to load the kernel */
- for(i = 0; i < ehdr->e_phnum; i++) {
-
- /* How much is in this segment? */
- run_size = phdr[i].p_memsz;
- if (phdr[i].p_type != PT_LOAD)
- seg_size = 0;
- else
- seg_size = (size_t)phdr[i].p_filesz;
-
- /* Where is it in the loaded file? */
- seg_addr = load_addr + phdr[i].p_offset;
- if (seg_addr + seg_size > load_addr + load_size) {
- printf("Fatal: ELF load segment runs off the "
- "end of the file.\n");
- exit(1);
- }
-
- /* Skip segments that don't take up any memory */
- if (run_size == 0) continue;
-
- /* Place the segment where it wants to be */
- run_addr = phdr[i].p_paddr;
- place_kernel_section(run_addr, run_size);
-
- /* Put it on the relocation list */
- if (seg_size < run_size) {
- /* Set up the kernel BSS too */
- if (seg_size > 0)
- add_section(run_addr, seg_addr, seg_size);
- bss_size = run_size - seg_size;
- add_section(run_addr + seg_size, NULL, bss_size);
- } else {
- /* No BSS */
- add_section(run_addr, seg_addr, run_size);
- }
- }
-
- /* Done! */
- return ehdr->e_entry;
- }
- }
-
- /* This is not a multiboot kernel */
- printf("Fatal: not a multiboot kernel.\n");
- exit(1);
-}
-
-
-
-static void load_module(struct mod_list *mod, char *cmdline)
- /* Load a multiboot module and allocate a memory area for it */
-{
- char *load_addr, *p;
- size_t load_size, run_addr;
-
- printf("Module: %s\n", cmdline);
-
- load_addr = 0;
- load_size = 0;
- p = strchr(cmdline, ' ');
- if (p != NULL) *p = 0;
- load_file(cmdline, &load_addr, &load_size);
- if (p != NULL) *p = ' ';
-
- /* Decide where it's going to live */
- run_addr = place_module_section(load_size, X86_PAGE_SIZE);
- if (run_addr == 0) {
- printf("Fatal: can't find space for this module.\n");
- exit(1);
- }
- add_section(run_addr, load_addr, load_size);
-
- /* Remember where we put it */
- mod->mod_start = run_addr;
- mod->mod_end = run_addr + load_size;
- mod->pad = 0;
-
-#ifdef DEBUG
- printf("Placed module (%#8.8x+%#x)\n", run_addr, load_size);
-#endif
-}
-
-
-
-
-/*
- * Code for shuffling sections into place and booting the new kernel
- */
-
-static void trampoline_start(section_t *secs, int sec_count,
- size_t mbi_run_addr, size_t entry)
- /* Final shuffle-and-boot code. Running on the stack; no external code
- * or data can be relied on. */
-{
- int i;
- struct lidt_operand idt;
-
- /* SYSLINUX has set up SS, DS and ES as 32-bit 0--4G data segments,
- * but doesn't specify FS and GS. Multiboot wants them all to be
- * the same, so we'd better do that before we overwrite the GDT. */
- asm volatile("movl %ds, %ecx; movl %ecx, %fs; movl %ecx, %gs");
-
- /* Turn off interrupts */
- asm volatile("cli");
-
- /* SYSLINUX has set up an IDT at 0x100000 that does all the
- * comboot calls, and we're about to overwrite it. The Multiboot
- * spec says that the kernel must set up its own IDT before turning
- * on interrupts, but it's still entitled to use BIOS calls, so we'll
- * put the IDT back to the BIOS one at the base of memory. */
- idt.base = 0;
- idt.limit = 0x800;
- asm volatile("lidt %0" : : "m" (idt));
-
- /* Now, shuffle the sections */
- for (i = 0; i < sec_count; i++) {
- if (secs[i].src == NULL) {
- /* asm bzero() code from com32/lib/memset.c */
- char *q = (char *) secs[i].dest;
- size_t nl = secs[i].size >> 2;
- asm volatile("cld ; rep ; stosl ; movl %3,%0 ; rep ; stosb"
- : "+c" (nl), "+D" (q)
- : "a" (0x0U), "r" (secs[i].size & 3));
- } else {
- /* asm memmove() code from com32/lib/memmove.c */
- const char *p = secs[i].src;
- char *q = (char *) secs[i].dest;
- size_t n = secs[i].size;
- if ( q < p ) {
- asm volatile("cld ; rep ; movsb"
- : "+c" (n), "+S" (p), "+D" (q));
- } else {
- p += (n-1);
- q += (n-1);
- asm volatile("std ; rep ; movsb"
- : "+c" (n), "+S" (p), "+D" (q));
- }
- }
- }
-
- /* Now set up the last tiny bit of Multiboot environment... */
-
- asm volatile(
-
- /* A20 is already enabled.
- * CR0 already has PG cleared and PE set.
- * EFLAGS already has VM and IF cleared.
- * ESP is the kernels' problem.
- * GDTR is the kernel's problem.
- * CS is already a 32-bit, 0--4G code segments.
- * DS, ES, FS and GS are already 32-bit, 0--4G data segments.
- * EBX must point to the MBI: */
-
- "movl %0, %%ebx;"
-
- /* EAX must be the Multiboot magic number. */
-
- "movl $0x2badb002, %%eax;"
-
- /* Start the kernel. */
-
- "jmp *%1"
-
- : : "m" (mbi_run_addr), "r" (entry));
-
-}
-static void trampoline_end(void) {}
-
-
-static void boot(size_t mbi_run_addr, size_t entry)
- /* Tidy up SYSLINUX, shuffle memory and boot the kernel */
-{
- com32sys_t regs;
- section_t *tr_sections;
- void (*trampoline)(section_t *, int, size_t, size_t);
- size_t trampoline_size;
-
- /* Make sure the relocations are safe. */
- reorder_sections();
-
- /* Copy the shuffle-and-boot code and the array of relocations
- * onto the memory we previously used for malloc() heap. This is
- * safe because it's not the source or the destination of any
- * copies, and there'll be no more library calls after the copy. */
-
- tr_sections = ((section_t *) section_addr) + section_count;
- trampoline = (void *) (tr_sections + section_count);
- trampoline_size = (void *)&trampoline_end - (void *)&trampoline_start;
-
-#ifdef DEBUG
- printf("tr_sections: %p\n"
- "trampoline: %p\n"
- "trampoline_size: %#8.8x\n"
- "max_run_addr: %#8.8x\n",
- tr_sections, trampoline, trampoline_size, max_run_addr);
-#endif
-
- printf("Booting: MBI=%#8.8x, entry=%#8.8x\n", mbi_run_addr, entry);
-
- memmove(tr_sections, section_addr, section_count * sizeof (section_t));
- memmove(trampoline, trampoline_start, trampoline_size);
-
- /* Tell SYSLINUX to clean up */
- regs.eax.l = 0x000c; /* "Perform final cleanup" */
- regs.edx.l = 0; /* "Normal cleanup" */
- __intcall(0x22, ®s, NULL);
-
- /* Into the unknown */
- trampoline(tr_sections, section_count, mbi_run_addr, entry);
-}
-
-
-int main(int argc, char **argv)
- /* Parse the command-line and invoke loaders */
-{
- struct multiboot_info *mbi;
- struct mod_list *modp;
- int modules;
- int mbi_reloc_offset;
- char *p;
- size_t mbi_run_addr, mbi_size, entry;
- int i;
-
- /* Say hello */
- console_ansi_std();
- printf("%s. %s\n", version_string, copyright_string);
-
- if (argc < 2 || !strcmp(argv[1], module_separator)) {
- printf("Fatal: No kernel filename!\n");
- exit(1);
- }
-
-#ifdef DEBUG
- printf("_end: %p\n"
- "argv[1]: %p\n"
- "next_load_addr: %p\n"
- "section_addr %p\n"
- "__mem_end: %p\n"
- "argv[0]: %p\n",
- &_end, argv[1], next_load_addr, section_addr, __mem_end, argv[0]);
-#endif
-
- /* How much space will the MBI need? */
- modules = 0;
- mbi_size = sizeof(struct multiboot_info) + strlen(version_string) + 5;
- for (i = 1 ; i < argc ; i++) {
- if (!strcmp(argv[i], module_separator)) {
- modules++;
- mbi_size += sizeof(struct mod_list) + 1;
- } else {
- mbi_size += strlen(argv[i]) + 1;
- }
- }
-
- /* Allocate space in the load buffer for the MBI, all the command
- * lines, and all the module details. */
- mbi = (struct multiboot_info *)next_load_addr;
- next_load_addr += mbi_size;
- if (next_load_addr > section_addr) {
- printf("Fatal: out of memory allocating for boot metadata.\n");
- exit(1);
- }
- memset(mbi, 0, sizeof (struct multiboot_info));
- p = (char *)(mbi + 1);
- mbi->flags = MB_INFO_CMDLINE | MB_INFO_BOOT_LOADER_NAME;
-
- /* Figure out the memory map.
- * N.B. Must happen before place_section() is called */
- init_mmap(mbi);
-
- mbi_run_addr = place_low_section(mbi_size, 4);
- if (mbi_run_addr == 0) {
- printf("Fatal: can't find space for the MBI!\n");
- exit(1);
- }
- mbi_reloc_offset = (size_t)mbi - mbi_run_addr;
- add_section(mbi_run_addr, (void *)mbi, mbi_size);
-
- /* Module info structs */
- modp = (struct mod_list *) (((size_t)p + 3) & ~3);
- if (modules > 0) mbi->flags |= MB_INFO_MODS;
- mbi->mods_count = modules;
- mbi->mods_addr = ((size_t)modp) - mbi_reloc_offset;
- p = (char *)(modp + modules);
-
- /* Command lines: first kernel, then modules */
- mbi->cmdline = ((size_t)p) - mbi_reloc_offset;
- modules = 0;
- for (i = 1 ; i < argc ; i++) {
- if (!strcmp(argv[i], module_separator)) {
- *p++ = '\0';
- modp[modules++].cmdline = ((size_t)p) - mbi_reloc_offset;
- } else {
- strcpy(p, argv[i]);
- p += strlen(argv[i]);
- *p++ = ' ';
- }
- }
- *p++ = '\0';
-
- /* Bootloader ID */
- strcpy(p, version_string);
- mbi->boot_loader_name = ((size_t)p) - mbi_reloc_offset;
- p += strlen(version_string) + 1;
-
- /* Now, do all the loading, and boot it */
- entry = load_kernel((char *)(mbi->cmdline + mbi_reloc_offset));
- for (i=0; i<modules; i++) {
- load_module(&(modp[i]), (char *)(modp[i].cmdline + mbi_reloc_offset));
- }
- boot(mbi_run_addr, entry);
-
- return 1;
-}
-
-/*
- * EOF
- */
git://git.onelab.eu / bootcd.git / blobdiff