arch/x86/kernel/head_64-xen.S

   1 /*
   2  *  linux/arch/x86_64/kernel/head.S -- start in 32bit and switch to 64bit
   3  *
   4  *  Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
   5  *  Copyright (C) 2000 Pavel Machek <pavel@suse.cz>
   6  *  Copyright (C) 2000 Karsten Keil <kkeil@suse.de>
   7  *  Copyright (C) 2001,2002 Andi Kleen <ak@suse.de>
   8  *  Copyright (C) 2005 Eric Biederman <ebiederm@xmission.com>
   9  *  Jun Nakajima <jun.nakajima@intel.com>
  10  *    Modified for Xen
  11  */
  12
  13
  14 #include <linux/linkage.h>
  15 #include <linux/threads.h>
  16 #include <linux/init.h>
  17 #include <linux/elfnote.h>
  18 #include <asm/segment.h>
  19 #include <asm/page.h>
  20 #include <asm/pgtable.h>
  21 #include <asm/msr.h>
  22 #include <asm/cache.h>
  23 #include <asm/dwarf2.h>
  24 #include <asm/percpu.h>
  25 #include <xen/interface/elfnote.h>
  26 #include <xen/interface/features.h>
  27
  28         __HEAD
  29         .code64
  30         .globl startup_64
  31 startup_64:
  32         movq $(init_thread_union+THREAD_SIZE-8),%rsp
  33
  34         /* rsi is pointer to startup info structure.
  35            pass it to C */
  36         movq %rsi,%rdi
  37
  38         /* Set up %gs.
  39          *
  40          * The base of %gs always points to the bottom of the irqstack
  41          * union.  If the stack protector canary is enabled, it is
  42          * located at %gs:40.  Note that, on SMP, the boot cpu uses
  43          * init data section till per cpu areas are set up.
  44          */
  45         movl    $MSR_GS_BASE,%ecx
  46         movq    $INIT_PER_CPU_VAR(irq_stack_union),%rax
  47         movq    %rax,%rdx
  48         shrq    $32,%rdx
  49         wrmsr
  50
  51         pushq $0                # fake return address
  52         jmp x86_64_start_kernel
  53
  54 #define NEXT_PAGE(name) \
  55         .balign PAGE_SIZE; \
  56 ENTRY(name)
  57
  58         __PAGE_ALIGNED_BSS
  59 NEXT_PAGE(init_level4_pgt)
  60         .fill   512,8,0
  61
  62 NEXT_PAGE(level3_kernel_pgt)
  63         .fill   512,8,0
  64
  65         /*
  66          * This is used for vsyscall area mapping as we have a different
  67          * level4 page table for user.
  68          */
  69 NEXT_PAGE(level3_user_pgt)
  70         .fill   512,8,0
  71
  72 NEXT_PAGE(level2_fixmap_pgt)
  73         .fill   512,8,0
  74
  75 NEXT_PAGE(level1_fixmap_pgt)
  76         .fill   512,8,0
  77
  78         .previous
  79 NEXT_PAGE(hypercall_page)
  80         phys_hypercall_page = . - .head.text
  81         CFI_STARTPROC
  82         .rept 0x1000 / 0x20
  83         .skip 1 /* push %rcx */
  84         CFI_ADJUST_CFA_OFFSET   8
  85         CFI_REL_OFFSET  rcx,0
  86         .skip 2 /* push %r11 */
  87         CFI_ADJUST_CFA_OFFSET   8
  88         CFI_REL_OFFSET  rcx,0
  89         .skip 5 /* mov $#,%eax */
  90         .skip 2 /* syscall */
  91         .skip 2 /* pop %r11 */
  92         CFI_ADJUST_CFA_OFFSET -8
  93         CFI_RESTORE r11
  94         .skip 1 /* pop %rcx */
  95         CFI_ADJUST_CFA_OFFSET -8
  96         CFI_RESTORE rcx
  97         .align 0x20,0 /* ret */
  98         .endr
  99         CFI_ENDPROC
 100
 101 #undef NEXT_PAGE
 102
 103         __PAGE_ALIGNED_BSS
 104         .align PAGE_SIZE
 105 ENTRY(empty_zero_page)
 106         .skip PAGE_SIZE
 107
 108 #ifdef CONFIG_XEN_UNPRIVILEGED_GUEST
 109 # define XEN_DOM0_CAP           0
 110 # define XEN_DOM0_CAP_STR       ""
 111 #else
 112 # define XEN_DOM0_CAP           (1 << XENFEAT_dom0)
 113 # if CONFIG_XEN_COMPAT < 0x040200
 114 #  define XEN_DOM0_CAP_STR      ""
 115 # else
 116 #  define XEN_DOM0_CAP_STR      "|dom0"
 117 # endif
 118 #endif
 119
 120 #if CONFIG_XEN_COMPAT <= 0x030002
 121 /*
 122  * __xen_guest information
 123  */
 124 .macro utoh value
 125  i = 64
 126  .rept 16
 127   i = i - 4
 128   .byte '0' + ((((\value) >> i) & 0xf) > 9) * ('0' - 'A' + 10) + (((\value) >> i) & 0xf)
 129  .endr
 130 .endm
 131
 132 .section __xen_guest
 133         .ascii  "GUEST_OS=linux,GUEST_VER=2.6"
 134         .ascii  ",XEN_VER=xen-3.0"
 135         .ascii  ",VIRT_BASE=0x"
 136                 utoh __START_KERNEL_map
 137         .ascii  ",ELF_PADDR_OFFSET=0x"
 138                 utoh __START_KERNEL_map
 139         .ascii  ",VIRT_ENTRY=0x"
 140                 utoh (__START_KERNEL_map + __PHYSICAL_START)
 141         .ascii  ",HYPERCALL_PAGE=0x"
 142                 utoh (phys_hypercall_page >> PAGE_SHIFT)
 143         .ascii  ",FEATURES=writable_page_tables"
 144         .ascii           "|writable_descriptor_tables"
 145         .ascii           "|auto_translated_physmap"
 146         .ascii           "|supervisor_mode_kernel"
 147         .ascii  ",LOADER=generic"
 148         .byte   0
 149 #endif /* CONFIG_XEN_COMPAT <= 0x030002 */
 150
 151         ELFNOTE(Xen, XEN_ELFNOTE_GUEST_OS,       .asciz "linux")
 152         ELFNOTE(Xen, XEN_ELFNOTE_GUEST_VERSION,  .asciz "2.6")
 153         ELFNOTE(Xen, XEN_ELFNOTE_XEN_VERSION,    .asciz "xen-3.0")
 154         ELFNOTE(Xen, XEN_ELFNOTE_VIRT_BASE,      .quad __START_KERNEL_map)
 155 #if CONFIG_XEN_COMPAT <= 0x030002
 156         ELFNOTE(Xen, XEN_ELFNOTE_PADDR_OFFSET,   .quad __START_KERNEL_map)
 157 #else
 158         ELFNOTE(Xen, XEN_ELFNOTE_PADDR_OFFSET,   .quad 0)
 159 #endif
 160         ELFNOTE(Xen, XEN_ELFNOTE_ENTRY,          .quad startup_64)
 161         ELFNOTE(Xen, XEN_ELFNOTE_HYPERCALL_PAGE, .quad hypercall_page)
 162         ELFNOTE(Xen, XEN_ELFNOTE_L1_MFN_VALID,   .quad _PAGE_PRESENT, _PAGE_PRESENT)
 163         ELFNOTE(Xen, XEN_ELFNOTE_MOD_START_PFN,  .long 1)
 164         ELFNOTE(Xen, XEN_ELFNOTE_INIT_P2M,       .quad VMEMMAP_START)
 165         ELFNOTE(Xen, XEN_ELFNOTE_FEATURES,       .ascii "writable_page_tables";
 166                                                  .ascii "|writable_descriptor_tables";
 167                                                  .ascii "|auto_translated_physmap";
 168                                                  .ascii "|supervisor_mode_kernel";
 169                                                  .asciz XEN_DOM0_CAP_STR)
 170         ELFNOTE(Xen, XEN_ELFNOTE_SUPPORTED_FEATURES, .long XEN_DOM0_CAP |
 171                                            (1 << XENFEAT_writable_page_tables) |
 172                                            (1 << XENFEAT_writable_descriptor_tables) |
 173                                            (1 << XENFEAT_auto_translated_physmap) |
 174                                            (1 << XENFEAT_supervisor_mode_kernel))
 175         ELFNOTE(Xen, XEN_ELFNOTE_LOADER,         .asciz "generic")
 176         ELFNOTE(Xen, XEN_ELFNOTE_SUSPEND_CANCEL, .long 1)