Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*
 * relocate_kernel.S - put the kernel image in place to boot
 * Copyright (C) 2002-2004 Eric Biederman  <ebiederm@xmission.com>
 *
 * This source code is licensed under the GNU General Public License,
 * Version 2.  See the file COPYING for more details.
 */

#include <linux/linkage.h>
#include <asm/page.h>
#include <asm/kexec.h>

/*
 * Must be relocatable PIC code callable as a C function
 */

#define PTR(x) (x << 2)
#define PAGE_ALIGNED (1 << PAGE_SHIFT)
#define PAGE_ATTR 0x63 /* _PAGE_PRESENT|_PAGE_RW|_PAGE_ACCESSED|_PAGE_DIRTY */
#define PAE_PGD_ATTR 0x01 /* _PAGE_PRESENT */

        .text
        .align PAGE_ALIGNED
        .globl relocate_kernel
relocate_kernel:
        movl    8(%esp), %ebp /* list of pages */

#ifdef CONFIG_X86_PAE
        /* map the control page at its virtual address */

        movl    PTR(VA_PGD)(%ebp), %edi
        movl    PTR(VA_CONTROL_PAGE)(%ebp), %eax
        andl    $0xc0000000, %eax
        shrl    $27, %eax
        addl    %edi, %eax

        movl    PTR(PA_PMD_0)(%ebp), %edx
        orl     $PAE_PGD_ATTR, %edx
        movl    %edx, (%eax)

        movl    PTR(VA_PMD_0)(%ebp), %edi
        movl    PTR(VA_CONTROL_PAGE)(%ebp), %eax
        andl    $0x3fe00000, %eax
        shrl    $18, %eax
        addl    %edi, %eax

        movl    PTR(PA_PTE_0)(%ebp), %edx
        orl     $PAGE_ATTR, %edx
        movl    %edx, (%eax)

        movl    PTR(VA_PTE_0)(%ebp), %edi
        movl    PTR(VA_CONTROL_PAGE)(%ebp), %eax
        andl    $0x001ff000, %eax
        shrl    $9, %eax
        addl    %edi, %eax

        movl    PTR(PA_CONTROL_PAGE)(%ebp), %edx
        orl     $PAGE_ATTR, %edx
        movl    %edx, (%eax)

        /* identity map the control page at its physical address */

        movl    PTR(VA_PGD)(%ebp), %edi
        movl    PTR(PA_CONTROL_PAGE)(%ebp), %eax
        andl    $0xc0000000, %eax
        shrl    $27, %eax
        addl    %edi, %eax

        movl    PTR(PA_PMD_1)(%ebp), %edx
        orl     $PAE_PGD_ATTR, %edx
        movl    %edx, (%eax)

        movl    PTR(VA_PMD_1)(%ebp), %edi
        movl    PTR(PA_CONTROL_PAGE)(%ebp), %eax
        andl    $0x3fe00000, %eax
        shrl    $18, %eax
        addl    %edi, %eax

        movl    PTR(PA_PTE_1)(%ebp), %edx
        orl     $PAGE_ATTR, %edx
        movl    %edx, (%eax)

        movl    PTR(VA_PTE_1)(%ebp), %edi
        movl    PTR(PA_CONTROL_PAGE)(%ebp), %eax
        andl    $0x001ff000, %eax
        shrl    $9, %eax
        addl    %edi, %eax

        movl    PTR(PA_CONTROL_PAGE)(%ebp), %edx
        orl     $PAGE_ATTR, %edx
        movl    %edx, (%eax)
#else
        /* map the control page at its virtual address */

        movl    PTR(VA_PGD)(%ebp), %edi
        movl    PTR(VA_CONTROL_PAGE)(%ebp), %eax
        andl    $0xffc00000, %eax
        shrl    $20, %eax
        addl    %edi, %eax

        movl    PTR(PA_PTE_0)(%ebp), %edx
        orl     $PAGE_ATTR, %edx
        movl    %edx, (%eax)

        movl    PTR(VA_PTE_0)(%ebp), %edi
        movl    PTR(VA_CONTROL_PAGE)(%ebp), %eax
        andl    $0x003ff000, %eax
        shrl    $10, %eax
        addl    %edi, %eax

        movl    PTR(PA_CONTROL_PAGE)(%ebp), %edx
        orl     $PAGE_ATTR, %edx
        movl    %edx, (%eax)

        /* identity map the control page at its physical address */

        movl    PTR(VA_PGD)(%ebp), %edi
        movl    PTR(PA_CONTROL_PAGE)(%ebp), %eax
        andl    $0xffc00000, %eax
        shrl    $20, %eax
        addl    %edi, %eax

        movl    PTR(PA_PTE_1)(%ebp), %edx
        orl     $PAGE_ATTR, %edx
        movl    %edx, (%eax)

        movl    PTR(VA_PTE_1)(%ebp), %edi
        movl    PTR(PA_CONTROL_PAGE)(%ebp), %eax
        andl    $0x003ff000, %eax
        shrl    $10, %eax
        addl    %edi, %eax

        movl    PTR(PA_CONTROL_PAGE)(%ebp), %edx
        orl     $PAGE_ATTR, %edx
        movl    %edx, (%eax)
#endif

relocate_new_kernel:
        /* read the arguments and say goodbye to the stack */
        movl  4(%esp), %ebx /* page_list */
        movl  8(%esp), %ebp /* list of pages */
        movl  12(%esp), %edx /* start address */
        movl  16(%esp), %ecx /* cpu_has_pae */

        /* zero out flags, and disable interrupts */
        pushl $0
        popfl

        /* get physical address of control page now */
        /* this is impossible after page table switch */
        movl    PTR(PA_CONTROL_PAGE)(%ebp), %edi

        /* switch to new set of page tables */
        movl    PTR(PA_PGD)(%ebp), %eax
        movl    %eax, %cr3

        /* setup a new stack at the end of the physical control page */
        lea     4096(%edi), %esp

        /* jump to identity mapped page */
        movl    %edi, %eax
        addl    $(identity_mapped - relocate_kernel), %eax
        pushl   %eax
        ret

identity_mapped:
        /* store the start address on the stack */
        pushl   %edx

        /* Set cr0 to a known state:
         * 31 0 == Paging disabled
         * 18 0 == Alignment check disabled
         * 16 0 == Write protect disabled
         * 3  0 == No task switch
         * 2  0 == Don't do FP software emulation.
         * 0  1 == Proctected mode enabled
         */
        movl    %cr0, %eax
        andl    $~((1<<31)|(1<<18)|(1<<16)|(1<<3)|(1<<2)), %eax
        orl     $(1<<0), %eax
        movl    %eax, %cr0

        /* clear cr4 if applicable */
        testl   %ecx, %ecx
        jz      1f
        /* Set cr4 to a known state:
         * Setting everything to zero seems safe.
         */
        movl    %cr4, %eax
        andl    $0, %eax
        movl    %eax, %cr4

        jmp 1f
1:

        /* Flush the TLB (needed?) */
        xorl    %eax, %eax
        movl    %eax, %cr3

        /* Do the copies */
        movl    %ebx, %ecx
        jmp     1f

0:      /* top, read another word from the indirection page */
        movl    (%ebx), %ecx
        addl    $4, %ebx
1:
        testl   $0x1,   %ecx  /* is it a destination page */
        jz      2f
        movl    %ecx,   %edi
        andl    $0xfffff000, %edi
        jmp     0b
2:
        testl   $0x2,   %ecx  /* is it an indirection page */
        jz      2f
        movl    %ecx,   %ebx
        andl    $0xfffff000, %ebx
        jmp     0b
2:
        testl   $0x4,   %ecx /* is it the done indicator */
        jz      2f
        jmp     3f
2:
        testl   $0x8,   %ecx /* is it the source indicator */
        jz      0b           /* Ignore it otherwise */
        movl    %ecx,   %esi /* For every source page do a copy */
        andl    $0xfffff000, %esi

        movl    $1024, %ecx
        rep ; movsl
        jmp     0b

3:

        /* To be certain of avoiding problems with self-modifying code
         * I need to execute a serializing instruction here.
         * So I flush the TLB, it's handy, and not processor dependent.
         */
        xorl    %eax, %eax
        movl    %eax, %cr3

        /* set all of the registers to known values */
        /* leave %esp alone */

        xorl    %eax, %eax
        xorl    %ebx, %ebx
        xorl    %ecx, %ecx
        xorl    %edx, %edx
        xorl    %esi, %esi
        xorl    %edi, %edi
        xorl    %ebp, %ebp
        ret