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    Subject[PATCH 12/20] x86_64: 64bit ACPI wakeup trampoline


    o Moved wakeup_level4_pgt into the wakeup routine so we can
    run the kernel above 4G.

    o Now we first go to 64bit mode and continue to run from trampoline and
    then then start accessing kernel symbols and restore processor context.
    This enables us to resume even in relocatable kernel context when
    kernel might not be loaded at physical addr it has been compiled for.

    o Removed the need for modifying any existing kernel page table.

    o Increased the size of the wakeup routine to 8K. This is required as
    wake page tables are on trampoline itself and they got to be at 4K
    boundary, hence one page is not sufficient.

    Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
    Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
    ---

    arch/x86_64/kernel/acpi/sleep.c | 22 ++------------
    arch/x86_64/kernel/acpi/wakeup.S | 59 ++++++++++++++++++++++++---------------
    arch/x86_64/kernel/head.S | 9 -----
    3 files changed, 41 insertions(+), 49 deletions(-)

    diff -puN arch/x86_64/kernel/acpi/sleep.c~x86_64-64bit-ACPI-wakeup-trampoline arch/x86_64/kernel/acpi/sleep.c
    --- linux-2.6.21-rc2-reloc/arch/x86_64/kernel/acpi/sleep.c~x86_64-64bit-ACPI-wakeup-trampoline 2007-03-07 01:28:11.000000000 +0530
    +++ linux-2.6.21-rc2-reloc-root/arch/x86_64/kernel/acpi/sleep.c 2007-03-07 01:28:11.000000000 +0530
    @@ -60,17 +60,6 @@ extern char wakeup_start, wakeup_end;

    extern unsigned long acpi_copy_wakeup_routine(unsigned long);

    -static pgd_t low_ptr;
    -
    -static void init_low_mapping(void)
    -{
    - pgd_t *slot0 = pgd_offset(current->mm, 0UL);
    - low_ptr = *slot0;
    - set_pgd(slot0, *pgd_offset(current->mm, PAGE_OFFSET));
    - WARN_ON(num_online_cpus() != 1);
    - local_flush_tlb();
    -}
    -
    /**
    * acpi_save_state_mem - save kernel state
    *
    @@ -79,8 +68,6 @@ static void init_low_mapping(void)
    */
    int acpi_save_state_mem(void)
    {
    - init_low_mapping();
    -
    memcpy((void *)acpi_wakeup_address, &wakeup_start,
    &wakeup_end - &wakeup_start);
    acpi_copy_wakeup_routine(acpi_wakeup_address);
    @@ -93,8 +80,6 @@ int acpi_save_state_mem(void)
    */
    void acpi_restore_state_mem(void)
    {
    - set_pgd(pgd_offset(current->mm, 0UL), low_ptr);
    - local_flush_tlb();
    }

    /**
    @@ -107,10 +92,11 @@ void acpi_restore_state_mem(void)
    */
    void __init acpi_reserve_bootmem(void)
    {
    - acpi_wakeup_address = (unsigned long)alloc_bootmem_low(PAGE_SIZE);
    - if ((&wakeup_end - &wakeup_start) > PAGE_SIZE)
    + acpi_wakeup_address = (unsigned long)alloc_bootmem_low(PAGE_SIZE*2);
    + if ((&wakeup_end - &wakeup_start) > (PAGE_SIZE*2))
    printk(KERN_CRIT
    - "ACPI: Wakeup code way too big, will crash on attempt to suspend\n");
    + "ACPI: Wakeup code way too big, will crash on attempt"
    + " to suspend\n");
    }

    static int __init acpi_sleep_setup(char *str)
    diff -puN arch/x86_64/kernel/acpi/wakeup.S~x86_64-64bit-ACPI-wakeup-trampoline arch/x86_64/kernel/acpi/wakeup.S
    --- linux-2.6.21-rc2-reloc/arch/x86_64/kernel/acpi/wakeup.S~x86_64-64bit-ACPI-wakeup-trampoline 2007-03-07 01:28:11.000000000 +0530
    +++ linux-2.6.21-rc2-reloc-root/arch/x86_64/kernel/acpi/wakeup.S 2007-03-07 01:28:11.000000000 +0530
    @@ -1,6 +1,7 @@
    .text
    #include <linux/linkage.h>
    #include <asm/segment.h>
    +#include <asm/pgtable.h>
    #include <asm/page.h>
    #include <asm/msr.h>

    @@ -62,12 +63,15 @@ wakeup_code:

    movb $0xa2, %al ; outb %al, $0x80

    - lidt %ds:idt_48a - wakeup_code
    - xorl %eax, %eax
    - movw %ds, %ax # (Convert %ds:gdt to a linear ptr)
    - shll $4, %eax
    - addl $(gdta - wakeup_code), %eax
    - movl %eax, gdt_48a +2 - wakeup_code
    + mov %ds, %ax # Find 32bit wakeup_code addr
    + movzx %ax, %esi # (Convert %ds:gdt to a liner ptr)
    + shll $4, %esi
    + # Fix up the vectors
    + addl %esi, wakeup_32_vector - wakeup_code
    + addl %esi, wakeup_long64_vector - wakeup_code
    + addl %esi, gdt_48a + 2 - wakeup_code # Fixup the gdt pointer
    +
    + lidtl %ds:idt_48a - wakeup_code
    lgdtl %ds:gdt_48a - wakeup_code # load gdt with whatever is
    # appropriate

    @@ -80,7 +84,7 @@ wakeup_code:

    .balign 4
    wakeup_32_vector:
    - .long wakeup_32 - __START_KERNEL_map
    + .long wakeup_32 - wakeup_code
    .word __KERNEL32_CS, 0

    .code32
    @@ -103,10 +107,6 @@ wakeup_32:
    movl $__KERNEL_DS, %eax
    movl %eax, %ds

    - movl saved_magic - __START_KERNEL_map, %eax
    - cmpl $0x9abcdef0, %eax
    - jne bogus_32_magic
    -
    movw $0x0e00 + 'i', %ds:(0xb8012)
    movb $0xa8, %al ; outb %al, $0x80;

    @@ -120,7 +120,7 @@ wakeup_32:
    movl %eax, %cr4

    /* Setup early boot stage 4 level pagetables */
    - movl $(wakeup_level4_pgt - __START_KERNEL_map), %eax
    + leal (wakeup_level4_pgt - wakeup_code)(%esi), %eax
    movl %eax, %cr3

    /* Enable Long Mode */
    @@ -159,11 +159,11 @@ wakeup_32:
    */

    /* Finally jump in 64bit mode */
    - ljmp *(wakeup_long64_vector - __START_KERNEL_map)
    + ljmp *(wakeup_long64_vector - wakeup_code)(%esi)

    .balign 4
    wakeup_long64_vector:
    - .long wakeup_long64 - __START_KERNEL_map
    + .long wakeup_long64 - wakeup_code
    .word __KERNEL_CS, 0

    .code64
    @@ -178,11 +178,16 @@ wakeup_long64:
    * addresses where we're currently running on. We have to do that here
    * because in 32bit we couldn't load a 64bit linear address.
    */
    - lgdt cpu_gdt_descr - __START_KERNEL_map
    + lgdt cpu_gdt_descr

    movw $0x0e00 + 'n', %ds:(0xb8014)
    movb $0xa9, %al ; outb %al, $0x80

    + movq saved_magic, %rax
    + movq $0x123456789abcdef0, %rdx
    + cmpq %rdx, %rax
    + jne bogus_64_magic
    +
    movw $0x0e00 + 'u', %ds:(0xb8016)

    nop
    @@ -223,20 +228,21 @@ idt_48a:
    gdt_48a:
    .word 0x800 # gdt limit=2048,
    # 256 GDT entries
    - .word 0, 0 # gdt base (filled in later)
    -
    + .long gdta - wakeup_code # gdt base (relocated in later)

    real_magic: .quad 0
    video_mode: .quad 0
    video_flags: .quad 0

    +.code16
    bogus_real_magic:
    movb $0xba,%al ; outb %al,$0x80
    jmp bogus_real_magic

    -bogus_32_magic:
    +.code64
    +bogus_64_magic:
    movb $0xb3,%al ; outb %al,$0x80
    - jmp bogus_32_magic
    + jmp bogus_64_magic

    bogus_cpu:
    movb $0xbc,%al ; outb %al,$0x80
    @@ -263,6 +269,7 @@ bogus_cpu:
    #define VIDEO_FIRST_V7 0x0900

    # Setting of user mode (AX=mode ID) => CF=success
    +.code16
    mode_seta:
    movw %ax, %bx
    #if 0
    @@ -313,6 +320,13 @@ wakeup_stack_begin: # Stack grows down
    .org 0xff0
    wakeup_stack: # Just below end of page

    +.org 0x1000
    +ENTRY(wakeup_level4_pgt)
    + .quad level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE
    + .fill 510,8,0
    + /* (2^48-(2*1024*1024*1024))/(2^39) = 511 */
    + .quad level3_kernel_pgt - __START_KERNEL_map + _KERNPG_TABLE
    +
    ENTRY(wakeup_end)

    ##
    @@ -338,9 +352,10 @@ ENTRY(acpi_copy_wakeup_routine)
    movq $0x123456789abcdef0, %rdx
    movq %rdx, saved_magic

    - movl saved_magic - __START_KERNEL_map, %eax
    - cmpl $0x9abcdef0, %eax
    - jne bogus_32_magic
    + movq saved_magic, %rax
    + movq $0x123456789abcdef0, %rdx
    + cmpq %rdx, %rax
    + jne bogus_64_magic

    # restore the regs we used
    popq %rdx
    diff -puN arch/x86_64/kernel/head.S~x86_64-64bit-ACPI-wakeup-trampoline arch/x86_64/kernel/head.S
    --- linux-2.6.21-rc2-reloc/arch/x86_64/kernel/head.S~x86_64-64bit-ACPI-wakeup-trampoline 2007-03-07 01:28:11.000000000 +0530
    +++ linux-2.6.21-rc2-reloc-root/arch/x86_64/kernel/head.S 2007-03-07 01:28:11.000000000 +0530
    @@ -308,15 +308,6 @@ NEXT_PAGE(level2_kernel_pgt)

    .data

    -#ifdef CONFIG_ACPI_SLEEP
    - .align PAGE_SIZE
    -ENTRY(wakeup_level4_pgt)
    - .quad level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE
    - .fill 510,8,0
    - /* (2^48-(2*1024*1024*1024))/(2^39) = 511 */
    - .quad level3_kernel_pgt - __START_KERNEL_map + _KERNPG_TABLE
    -#endif
    -
    #ifndef CONFIG_HOTPLUG_CPU
    __INITDATA
    #endif
    _
    -
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