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main.c

/*
 * Copyright (C) Paul Mackerras 1997.
 *
 * Updates for PPC64 by Todd Inglett, Dave Engebretsen & Peter Bergner.
 *
 * 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.
 */
#include <stdarg.h>
#include <stddef.h>
#include "elf.h"
#include "page.h"
#include "string.h"
#include "stdio.h"
#include "ops.h"
#include "gunzip_util.h"
#include "reg.h"

static struct gunzip_state gzstate;

struct addr_range {
      void *addr;
      unsigned long size;
};

#undef DEBUG

static struct addr_range prep_kernel(void)
{
      char elfheader[256];
      void *vmlinuz_addr = _vmlinux_start;
      unsigned long vmlinuz_size = _vmlinux_end - _vmlinux_start;
      void *addr = 0;
      struct elf_info ei;
      int len;

      /* gunzip the ELF header of the kernel */
      gunzip_start(&gzstate, vmlinuz_addr, vmlinuz_size);
      gunzip_exactly(&gzstate, elfheader, sizeof(elfheader));

      if (!parse_elf64(elfheader, &ei) && !parse_elf32(elfheader, &ei))
            fatal("Error: not a valid PPC32 or PPC64 ELF file!\n\r");

      if (platform_ops.image_hdr)
            platform_ops.image_hdr(elfheader);

      /* We need to alloc the memsize: gzip will expand the kernel
       * text/data, then possible rubbish we don't care about. But
       * the kernel bss must be claimed (it will be zero'd by the
       * kernel itself)
       */
      printf("Allocating 0x%lx bytes for kernel ...\n\r", ei.memsize);

      if (platform_ops.vmlinux_alloc) {
            addr = platform_ops.vmlinux_alloc(ei.memsize);
      } else {
            /*
             * Check if the kernel image (without bss) would overwrite the
             * bootwrapper. The device tree has been moved in fdt_init()
             * to an area allocated with malloc() (somewhere past _end).
             */
            if ((unsigned long)_start < ei.loadsize)
                  fatal("Insufficient memory for kernel at address 0!"
                         " (_start=%p, uncompressed size=%08lx)\n\r",
                         _start, ei.loadsize);

            if ((unsigned long)_end < ei.memsize)
                  fatal("The final kernel image would overwrite the "
                              "device tree\n\r");
      }

      /* Finally, gunzip the kernel */
      printf("gunzipping (0x%p <- 0x%p:0x%p)...", addr,
             vmlinuz_addr, vmlinuz_addr+vmlinuz_size);
      /* discard up to the actual load data */
      gunzip_discard(&gzstate, ei.elfoffset - sizeof(elfheader));
      len = gunzip_finish(&gzstate, addr, ei.loadsize);
      if (len != ei.loadsize)
            fatal("ran out of data!  only got 0x%x of 0x%lx bytes.\n\r",
                        len, ei.loadsize);
      printf("done 0x%x bytes\n\r", len);

      flush_cache(addr, ei.loadsize);

      return (struct addr_range){addr, ei.memsize};
}

static struct addr_range prep_initrd(struct addr_range vmlinux, void *chosen,
                             unsigned long initrd_addr,
                             unsigned long initrd_size)
{
      /* If we have an image attached to us, it overrides anything
       * supplied by the loader. */
      if (_initrd_end > _initrd_start) {
            printf("Attached initrd image at 0x%p-0x%p\n\r",
                   _initrd_start, _initrd_end);
            initrd_addr = (unsigned long)_initrd_start;
            initrd_size = _initrd_end - _initrd_start;
      } else if (initrd_size > 0) {
            printf("Using loader supplied ramdisk at 0x%lx-0x%lx\n\r",
                   initrd_addr, initrd_addr + initrd_size);
      }

      /* If there's no initrd at all, we're done */
      if (! initrd_size)
            return (struct addr_range){0, 0};

      /*
       * If the initrd is too low it will be clobbered when the
       * kernel relocates to its final location.  In this case,
       * allocate a safer place and move it.
       */
      if (initrd_addr < vmlinux.size) {
            void *old_addr = (void *)initrd_addr;

            printf("Allocating 0x%lx bytes for initrd ...\n\r",
                   initrd_size);
            initrd_addr = (unsigned long)malloc(initrd_size);
            if (! initrd_addr)
                  fatal("Can't allocate memory for initial "
                         "ramdisk !\n\r");
            printf("Relocating initrd 0x%lx <- 0x%p (0x%lx bytes)\n\r",
                   initrd_addr, old_addr, initrd_size);
            memmove((void *)initrd_addr, old_addr, initrd_size);
      }

      printf("initrd head: 0x%lx\n\r", *((unsigned long *)initrd_addr));

      /* Tell the kernel initrd address via device tree */
      setprop_val(chosen, "linux,initrd-start", (u32)(initrd_addr));
      setprop_val(chosen, "linux,initrd-end", (u32)(initrd_addr+initrd_size));

      return (struct addr_range){(void *)initrd_addr, initrd_size};
}

/* A buffer that may be edited by tools operating on a zImage binary so as to
 * edit the command line passed to vmlinux (by setting /chosen/bootargs).
 * The buffer is put in it's own section so that tools may locate it easier.
 */
static char cmdline[COMMAND_LINE_SIZE]
      __attribute__((__section__("__builtin_cmdline")));

static void prep_cmdline(void *chosen)
{
      if (cmdline[0] == '\0')
            getprop(chosen, "bootargs", cmdline, COMMAND_LINE_SIZE-1);

      printf("\n\rLinux/PowerPC load: %s", cmdline);
      /* If possible, edit the command line */
      if (console_ops.edit_cmdline)
            console_ops.edit_cmdline(cmdline, COMMAND_LINE_SIZE);
      printf("\n\r");

      /* Put the command line back into the devtree for the kernel */
      setprop_str(chosen, "bootargs", cmdline);
}

struct platform_ops platform_ops;
struct dt_ops dt_ops;
struct console_ops console_ops;
struct loader_info loader_info;

void start(void)
{
      struct addr_range vmlinux, initrd;
      kernel_entry_t kentry;
      unsigned long ft_addr = 0;
      void *chosen;

      /* Do this first, because malloc() could clobber the loader's
       * command line.  Only use the loader command line if a
       * built-in command line wasn't set by an external tool */
      if ((loader_info.cmdline_len > 0) && (cmdline[0] == '\0'))
            memmove(cmdline, loader_info.cmdline,
                  min(loader_info.cmdline_len, COMMAND_LINE_SIZE-1));

      if (console_ops.open && (console_ops.open() < 0))
            exit();
      if (platform_ops.fixups)
            platform_ops.fixups();

      printf("\n\rzImage starting: loaded at 0x%p (sp: 0x%p)\n\r",
             _start, get_sp());

      /* Ensure that the device tree has a /chosen node */
      chosen = finddevice("/chosen");
      if (!chosen)
            chosen = create_node(NULL, "chosen");

      vmlinux = prep_kernel();
      initrd = prep_initrd(vmlinux, chosen,
                       loader_info.initrd_addr, loader_info.initrd_size);
      prep_cmdline(chosen);

      printf("Finalizing device tree...");
      if (dt_ops.finalize)
            ft_addr = dt_ops.finalize();
      if (ft_addr)
            printf(" flat tree at 0x%lx\n\r", ft_addr);
      else
            printf(" using OF tree (promptr=%p)\n\r", loader_info.promptr);

      if (console_ops.close)
            console_ops.close();

      kentry = (kernel_entry_t) vmlinux.addr;
      if (ft_addr)
            kentry(ft_addr, 0, NULL);
      else
            kentry((unsigned long)initrd.addr, initrd.size,
                   loader_info.promptr);

      /* console closed so printf in fatal below may not work */
      fatal("Error: Linux kernel returned to zImage boot wrapper!\n\r");
}

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