arch/x86/kernel/relocate_kernel_32.S

   1 /*
   2  * relocate_kernel.S - put the kernel image in place to boot
   3  * Copyright (C) 2002-2004 Eric Biederman  <ebiederm@xmission.com>
   4  *
   5  * This source code is licensed under the GNU General Public License,
   6  * Version 2.  See the file COPYING for more details.
   7  */
   8
   9 #include <linux/linkage.h>
  10 #include <asm/page.h>
  11 #include <asm/kexec.h>
  12 #include <asm/processor-flags.h>
  13 #include <asm/pgtable.h>
  14
  15 /*
  16  * Must be relocatable PIC code callable as a C function
  17  */
  18
  19 #define PTR(x) (x << 2)
  20 #define PAGE_ATTR (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY)
  21 #define PAE_PGD_ATTR (_PAGE_PRESENT)
  22
  23         .text
  24         .align PAGE_SIZE
  25         .globl relocate_kernel
  26 relocate_kernel:
  27         movl    8(%esp), %ebp /* list of pages */
  28
  29 #ifdef CONFIG_X86_PAE
  30         /* map the control page at its virtual address */
  31
  32         movl    PTR(VA_PGD)(%ebp), %edi
  33         movl    PTR(VA_CONTROL_PAGE)(%ebp), %eax
  34         andl    $0xc0000000, %eax
  35         shrl    $27, %eax
  36         addl    %edi, %eax
  37
  38         movl    PTR(PA_PMD_0)(%ebp), %edx
  39         orl     $PAE_PGD_ATTR, %edx
  40         movl    %edx, (%eax)
  41
  42         movl    PTR(VA_PMD_0)(%ebp), %edi
  43         movl    PTR(VA_CONTROL_PAGE)(%ebp), %eax
  44         andl    $0x3fe00000, %eax
  45         shrl    $18, %eax
  46         addl    %edi, %eax
  47
  48         movl    PTR(PA_PTE_0)(%ebp), %edx
  49         orl     $PAGE_ATTR, %edx
  50         movl    %edx, (%eax)
  51
  52         movl    PTR(VA_PTE_0)(%ebp), %edi
  53         movl    PTR(VA_CONTROL_PAGE)(%ebp), %eax
  54         andl    $0x001ff000, %eax
  55         shrl    $9, %eax
  56         addl    %edi, %eax
  57
  58         movl    PTR(PA_CONTROL_PAGE)(%ebp), %edx
  59         orl     $PAGE_ATTR, %edx
  60         movl    %edx, (%eax)
  61
  62         /* identity map the control page at its physical address */
  63
  64         movl    PTR(VA_PGD)(%ebp), %edi
  65         movl    PTR(PA_CONTROL_PAGE)(%ebp), %eax
  66         andl    $0xc0000000, %eax
  67         shrl    $27, %eax
  68         addl    %edi, %eax
  69
  70         movl    PTR(PA_PMD_1)(%ebp), %edx
  71         orl     $PAE_PGD_ATTR, %edx
  72         movl    %edx, (%eax)
  73
  74         movl    PTR(VA_PMD_1)(%ebp), %edi
  75         movl    PTR(PA_CONTROL_PAGE)(%ebp), %eax
  76         andl    $0x3fe00000, %eax
  77         shrl    $18, %eax
  78         addl    %edi, %eax
  79
  80         movl    PTR(PA_PTE_1)(%ebp), %edx
  81         orl     $PAGE_ATTR, %edx
  82         movl    %edx, (%eax)
  83
  84         movl    PTR(VA_PTE_1)(%ebp), %edi
  85         movl    PTR(PA_CONTROL_PAGE)(%ebp), %eax
  86         andl    $0x001ff000, %eax
  87         shrl    $9, %eax
  88         addl    %edi, %eax
  89
  90         movl    PTR(PA_CONTROL_PAGE)(%ebp), %edx
  91         orl     $PAGE_ATTR, %edx
  92         movl    %edx, (%eax)
  93 #else
  94         /* map the control page at its virtual address */
  95
  96         movl    PTR(VA_PGD)(%ebp), %edi
  97         movl    PTR(VA_CONTROL_PAGE)(%ebp), %eax
  98         andl    $0xffc00000, %eax
  99         shrl    $20, %eax
 100         addl    %edi, %eax
 101
 102         movl    PTR(PA_PTE_0)(%ebp), %edx
 103         orl     $PAGE_ATTR, %edx
 104         movl    %edx, (%eax)
 105
 106         movl    PTR(VA_PTE_0)(%ebp), %edi
 107         movl    PTR(VA_CONTROL_PAGE)(%ebp), %eax
 108         andl    $0x003ff000, %eax
 109         shrl    $10, %eax
 110         addl    %edi, %eax
 111
 112         movl    PTR(PA_CONTROL_PAGE)(%ebp), %edx
 113         orl     $PAGE_ATTR, %edx
 114         movl    %edx, (%eax)
 115
 116         /* identity map the control page at its physical address */
 117
 118         movl    PTR(VA_PGD)(%ebp), %edi
 119         movl    PTR(PA_CONTROL_PAGE)(%ebp), %eax
 120         andl    $0xffc00000, %eax
 121         shrl    $20, %eax
 122         addl    %edi, %eax
 123
 124         movl    PTR(PA_PTE_1)(%ebp), %edx
 125         orl     $PAGE_ATTR, %edx
 126         movl    %edx, (%eax)
 127
 128         movl    PTR(VA_PTE_1)(%ebp), %edi
 129         movl    PTR(PA_CONTROL_PAGE)(%ebp), %eax
 130         andl    $0x003ff000, %eax
 131         shrl    $10, %eax
 132         addl    %edi, %eax
 133
 134         movl    PTR(PA_CONTROL_PAGE)(%ebp), %edx
 135         orl     $PAGE_ATTR, %edx
 136         movl    %edx, (%eax)
 137 #endif
 138
 139 relocate_new_kernel:
 140         /* read the arguments and say goodbye to the stack */
 141         movl  4(%esp), %ebx /* page_list */
 142         movl  8(%esp), %ebp /* list of pages */
 143         movl  12(%esp), %edx /* start address */
 144         movl  16(%esp), %ecx /* cpu_has_pae */
 145
 146         /* zero out flags, and disable interrupts */
 147         pushl $0
 148         popfl
 149
 150         /* get physical address of control page now */
 151         /* this is impossible after page table switch */
 152         movl    PTR(PA_CONTROL_PAGE)(%ebp), %edi
 153
 154         /* switch to new set of page tables */
 155         movl    PTR(PA_PGD)(%ebp), %eax
 156         movl    %eax, %cr3
 157
 158         /* setup a new stack at the end of the physical control page */
 159         lea     PAGE_SIZE(%edi), %esp
 160
 161         /* jump to identity mapped page */
 162         movl    %edi, %eax
 163         addl    $(identity_mapped - relocate_kernel), %eax
 164         pushl   %eax
 165         ret
 166
 167 identity_mapped:
 168         /* store the start address on the stack */
 169         pushl   %edx
 170
 171         /* Set cr0 to a known state:
 172          *  - Paging disabled
 173          *  - Alignment check disabled
 174          *  - Write protect disabled
 175          *  - No task switch
 176          *  - Don't do FP software emulation.
 177          *  - Proctected mode enabled
 178          */
 179         movl    %cr0, %eax
 180         andl    $~(X86_CR0_PG | X86_CR0_AM | X86_CR0_WP | X86_CR0_TS | X86_CR0_EM), %eax
 181         orl     $(X86_CR0_PE), %eax
 182         movl    %eax, %cr0
 183
 184         /* clear cr4 if applicable */
 185         testl   %ecx, %ecx
 186         jz      1f
 187         /* Set cr4 to a known state:
 188          * Setting everything to zero seems safe.
 189          */
 190         xorl    %eax, %eax
 191         movl    %eax, %cr4
 192
 193         jmp 1f
 194 1:
 195
 196         /* Flush the TLB (needed?) */
 197         xorl    %eax, %eax
 198         movl    %eax, %cr3
 199
 200         /* Do the copies */
 201         movl    %ebx, %ecx
 202         jmp     1f
 203
 204 0:      /* top, read another word from the indirection page */
 205         movl    (%ebx), %ecx
 206         addl    $4, %ebx
 207 1:
 208         testl   $0x1,   %ecx  /* is it a destination page */
 209         jz      2f
 210         movl    %ecx,   %edi
 211         andl    $0xfffff000, %edi
 212         jmp     0b
 213 2:
 214         testl   $0x2,   %ecx  /* is it an indirection page */
 215         jz      2f
 216         movl    %ecx,   %ebx
 217         andl    $0xfffff000, %ebx
 218         jmp     0b
 219 2:
 220         testl   $0x4,   %ecx /* is it the done indicator */
 221         jz      2f
 222         jmp     3f
 223 2:
 224         testl   $0x8,   %ecx /* is it the source indicator */
 225         jz      0b           /* Ignore it otherwise */
 226         movl    %ecx,   %esi /* For every source page do a copy */
 227         andl    $0xfffff000, %esi
 228
 229         movl    $1024, %ecx
 230         rep ; movsl
 231         jmp     0b
 232
 233 3:
 234
 235         /* To be certain of avoiding problems with self-modifying code
 236          * I need to execute a serializing instruction here.
 237          * So I flush the TLB, it's handy, and not processor dependent.
 238          */
 239         xorl    %eax, %eax
 240         movl    %eax, %cr3
 241
 242         /* set all of the registers to known values */
 243         /* leave %esp alone */
 244
 245         xorl    %eax, %eax
 246         xorl    %ebx, %ebx
 247         xorl    %ecx, %ecx
 248         xorl    %edx, %edx
 249         xorl    %esi, %esi
 250         xorl    %edi, %edi
 251         xorl    %ebp, %ebp
 252         ret