linux/arch/powerpc/boot/main.c
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   1/*
   2 * Copyright (C) Paul Mackerras 1997.
   3 *
   4 * Updates for PPC64 by Todd Inglett, Dave Engebretsen & Peter Bergner.
   5 *
   6 * This program is free software; you can redistribute it and/or
   7 * modify it under the terms of the GNU General Public License
   8 * as published by the Free Software Foundation; either version
   9 * 2 of the License, or (at your option) any later version.
  10 */
  11#include <stdarg.h>
  12#include <stddef.h>
  13#include "elf.h"
  14#include "page.h"
  15#include "string.h"
  16#include "stdio.h"
  17#include "ops.h"
  18#include "gunzip_util.h"
  19#include "reg.h"
  20
  21static struct gunzip_state gzstate;
  22
  23struct addr_range {
  24        void *addr;
  25        unsigned long size;
  26};
  27
  28#undef DEBUG
  29
  30static struct addr_range prep_kernel(void)
  31{
  32        char elfheader[256];
  33        void *vmlinuz_addr = _vmlinux_start;
  34        unsigned long vmlinuz_size = _vmlinux_end - _vmlinux_start;
  35        void *addr = 0;
  36        struct elf_info ei;
  37        int len;
  38
  39        /* gunzip the ELF header of the kernel */
  40        gunzip_start(&gzstate, vmlinuz_addr, vmlinuz_size);
  41        gunzip_exactly(&gzstate, elfheader, sizeof(elfheader));
  42
  43        if (!parse_elf64(elfheader, &ei) && !parse_elf32(elfheader, &ei))
  44                fatal("Error: not a valid PPC32 or PPC64 ELF file!\n\r");
  45
  46        if (platform_ops.image_hdr)
  47                platform_ops.image_hdr(elfheader);
  48
  49        /* We need to alloc the memsize: gzip will expand the kernel
  50         * text/data, then possible rubbish we don't care about. But
  51         * the kernel bss must be claimed (it will be zero'd by the
  52         * kernel itself)
  53         */
  54        printf("Allocating 0x%lx bytes for kernel ...\n\r", ei.memsize);
  55
  56        if (platform_ops.vmlinux_alloc) {
  57                addr = platform_ops.vmlinux_alloc(ei.memsize);
  58        } else {
  59                /*
  60                 * Check if the kernel image (without bss) would overwrite the
  61                 * bootwrapper. The device tree has been moved in fdt_init()
  62                 * to an area allocated with malloc() (somewhere past _end).
  63                 */
  64                if ((unsigned long)_start < ei.loadsize)
  65                        fatal("Insufficient memory for kernel at address 0!"
  66                               " (_start=%p, uncompressed size=%08lx)\n\r",
  67                               _start, ei.loadsize);
  68
  69                if ((unsigned long)_end < ei.memsize)
  70                        fatal("The final kernel image would overwrite the "
  71                                        "device tree\n\r");
  72        }
  73
  74        /* Finally, gunzip the kernel */
  75        printf("gunzipping (0x%p <- 0x%p:0x%p)...", addr,
  76               vmlinuz_addr, vmlinuz_addr+vmlinuz_size);
  77        /* discard up to the actual load data */
  78        gunzip_discard(&gzstate, ei.elfoffset - sizeof(elfheader));
  79        len = gunzip_finish(&gzstate, addr, ei.loadsize);
  80        if (len != ei.loadsize)
  81                fatal("ran out of data!  only got 0x%x of 0x%lx bytes.\n\r",
  82                                len, ei.loadsize);
  83        printf("done 0x%x bytes\n\r", len);
  84
  85        flush_cache(addr, ei.loadsize);
  86
  87        return (struct addr_range){addr, ei.memsize};
  88}
  89
  90static struct addr_range prep_initrd(struct addr_range vmlinux, void *chosen,
  91                                     unsigned long initrd_addr,
  92                                     unsigned long initrd_size)
  93{
  94        /* If we have an image attached to us, it overrides anything
  95         * supplied by the loader. */
  96        if (_initrd_end > _initrd_start) {
  97                printf("Attached initrd image at 0x%p-0x%p\n\r",
  98                       _initrd_start, _initrd_end);
  99                initrd_addr = (unsigned long)_initrd_start;
 100                initrd_size = _initrd_end - _initrd_start;
 101        } else if (initrd_size > 0) {
 102                printf("Using loader supplied ramdisk at 0x%lx-0x%lx\n\r",
 103                       initrd_addr, initrd_addr + initrd_size);
 104        }
 105
 106        /* If there's no initrd at all, we're done */
 107        if (! initrd_size)
 108                return (struct addr_range){0, 0};
 109
 110        /*
 111         * If the initrd is too low it will be clobbered when the
 112         * kernel relocates to its final location.  In this case,
 113         * allocate a safer place and move it.
 114         */
 115        if (initrd_addr < vmlinux.size) {
 116                void *old_addr = (void *)initrd_addr;
 117
 118                printf("Allocating 0x%lx bytes for initrd ...\n\r",
 119                       initrd_size);
 120                initrd_addr = (unsigned long)malloc(initrd_size);
 121                if (! initrd_addr)
 122                        fatal("Can't allocate memory for initial "
 123                               "ramdisk !\n\r");
 124                printf("Relocating initrd 0x%lx <- 0x%p (0x%lx bytes)\n\r",
 125                       initrd_addr, old_addr, initrd_size);
 126                memmove((void *)initrd_addr, old_addr, initrd_size);
 127        }
 128
 129        printf("initrd head: 0x%lx\n\r", *((unsigned long *)initrd_addr));
 130
 131        /* Tell the kernel initrd address via device tree */
 132        setprop_val(chosen, "linux,initrd-start", (u32)(initrd_addr));
 133        setprop_val(chosen, "linux,initrd-end", (u32)(initrd_addr+initrd_size));
 134
 135        return (struct addr_range){(void *)initrd_addr, initrd_size};
 136}
 137
 138/* A buffer that may be edited by tools operating on a zImage binary so as to
 139 * edit the command line passed to vmlinux (by setting /chosen/bootargs).
 140 * The buffer is put in it's own section so that tools may locate it easier.
 141 */
 142static char cmdline[COMMAND_LINE_SIZE]
 143        __attribute__((__section__("__builtin_cmdline")));
 144
 145static void prep_cmdline(void *chosen)
 146{
 147        if (cmdline[0] == '\0')
 148                getprop(chosen, "bootargs", cmdline, COMMAND_LINE_SIZE-1);
 149
 150        printf("\n\rLinux/PowerPC load: %s", cmdline);
 151        /* If possible, edit the command line */
 152        if (console_ops.edit_cmdline)
 153                console_ops.edit_cmdline(cmdline, COMMAND_LINE_SIZE);
 154        printf("\n\r");
 155
 156        /* Put the command line back into the devtree for the kernel */
 157        setprop_str(chosen, "bootargs", cmdline);
 158}
 159
 160struct platform_ops platform_ops;
 161struct dt_ops dt_ops;
 162struct console_ops console_ops;
 163struct loader_info loader_info;
 164
 165void start(void)
 166{
 167        struct addr_range vmlinux, initrd;
 168        kernel_entry_t kentry;
 169        unsigned long ft_addr = 0;
 170        void *chosen;
 171
 172        /* Do this first, because malloc() could clobber the loader's
 173         * command line.  Only use the loader command line if a
 174         * built-in command line wasn't set by an external tool */
 175        if ((loader_info.cmdline_len > 0) && (cmdline[0] == '\0'))
 176                memmove(cmdline, loader_info.cmdline,
 177                        min(loader_info.cmdline_len, COMMAND_LINE_SIZE-1));
 178
 179        if (console_ops.open && (console_ops.open() < 0))
 180                exit();
 181        if (platform_ops.fixups)
 182                platform_ops.fixups();
 183
 184        printf("\n\rzImage starting: loaded at 0x%p (sp: 0x%p)\n\r",
 185               _start, get_sp());
 186
 187        /* Ensure that the device tree has a /chosen node */
 188        chosen = finddevice("/chosen");
 189        if (!chosen)
 190                chosen = create_node(NULL, "chosen");
 191
 192        vmlinux = prep_kernel();
 193        initrd = prep_initrd(vmlinux, chosen,
 194                             loader_info.initrd_addr, loader_info.initrd_size);
 195        prep_cmdline(chosen);
 196
 197        printf("Finalizing device tree...");
 198        if (dt_ops.finalize)
 199                ft_addr = dt_ops.finalize();
 200        if (ft_addr)
 201                printf(" flat tree at 0x%lx\n\r", ft_addr);
 202        else
 203                printf(" using OF tree (promptr=%p)\n\r", loader_info.promptr);
 204
 205        if (console_ops.close)
 206                console_ops.close();
 207
 208        kentry = (kernel_entry_t) vmlinux.addr;
 209        if (ft_addr)
 210                kentry(ft_addr, 0, NULL);
 211        else
 212                kentry((unsigned long)initrd.addr, initrd.size,
 213                       loader_info.promptr);
 214
 215        /* console closed so printf in fatal below may not work */
 216        fatal("Error: Linux kernel returned to zImage boot wrapper!\n\r");
 217}
 218