summaryrefslogtreecommitdiffstats
path: root/arch/x86/kernel/head_64.S
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--arch/x86/kernel/head_64.S674
1 files changed, 674 insertions, 0 deletions
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
new file mode 100644
index 000000000..998cdb112
--- /dev/null
+++ b/arch/x86/kernel/head_64.S
@@ -0,0 +1,674 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * linux/arch/x86/kernel/head_64.S -- start in 32bit and switch to 64bit
+ *
+ * Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
+ * Copyright (C) 2000 Pavel Machek <pavel@suse.cz>
+ * Copyright (C) 2000 Karsten Keil <kkeil@suse.de>
+ * Copyright (C) 2001,2002 Andi Kleen <ak@suse.de>
+ * Copyright (C) 2005 Eric Biederman <ebiederm@xmission.com>
+ */
+
+
+#include <linux/linkage.h>
+#include <linux/threads.h>
+#include <linux/init.h>
+#include <linux/pgtable.h>
+#include <asm/segment.h>
+#include <asm/page.h>
+#include <asm/msr.h>
+#include <asm/cache.h>
+#include <asm/processor-flags.h>
+#include <asm/percpu.h>
+#include <asm/nops.h>
+#include "../entry/calling.h"
+#include <asm/export.h>
+#include <asm/nospec-branch.h>
+#include <asm/fixmap.h>
+
+/*
+ * We are not able to switch in one step to the final KERNEL ADDRESS SPACE
+ * because we need identity-mapped pages.
+ */
+#define l4_index(x) (((x) >> 39) & 511)
+#define pud_index(x) (((x) >> PUD_SHIFT) & (PTRS_PER_PUD-1))
+
+L4_PAGE_OFFSET = l4_index(__PAGE_OFFSET_BASE_L4)
+L4_START_KERNEL = l4_index(__START_KERNEL_map)
+
+L3_START_KERNEL = pud_index(__START_KERNEL_map)
+
+ .text
+ __HEAD
+ .code64
+SYM_CODE_START_NOALIGN(startup_64)
+ UNWIND_HINT_EMPTY
+ /*
+ * At this point the CPU runs in 64bit mode CS.L = 1 CS.D = 0,
+ * and someone has loaded an identity mapped page table
+ * for us. These identity mapped page tables map all of the
+ * kernel pages and possibly all of memory.
+ *
+ * %rsi holds a physical pointer to real_mode_data.
+ *
+ * We come here either directly from a 64bit bootloader, or from
+ * arch/x86/boot/compressed/head_64.S.
+ *
+ * We only come here initially at boot nothing else comes here.
+ *
+ * Since we may be loaded at an address different from what we were
+ * compiled to run at we first fixup the physical addresses in our page
+ * tables and then reload them.
+ */
+
+ /* Set up the stack for verify_cpu(), similar to initial_stack below */
+ leaq (__end_init_task - FRAME_SIZE)(%rip), %rsp
+
+ leaq _text(%rip), %rdi
+
+ /*
+ * initial_gs points to initial fixed_percpu_data struct with storage for
+ * the stack protector canary. Global pointer fixups are needed at this
+ * stage, so apply them as is done in fixup_pointer(), and initialize %gs
+ * such that the canary can be accessed at %gs:40 for subsequent C calls.
+ */
+ movl $MSR_GS_BASE, %ecx
+ movq initial_gs(%rip), %rax
+ movq $_text, %rdx
+ subq %rdx, %rax
+ addq %rdi, %rax
+ movq %rax, %rdx
+ shrq $32, %rdx
+ wrmsr
+
+ pushq %rsi
+ call startup_64_setup_env
+ popq %rsi
+
+ /* Now switch to __KERNEL_CS so IRET works reliably */
+ pushq $__KERNEL_CS
+ leaq .Lon_kernel_cs(%rip), %rax
+ pushq %rax
+ lretq
+
+.Lon_kernel_cs:
+ UNWIND_HINT_EMPTY
+
+#ifdef CONFIG_AMD_MEM_ENCRYPT
+ /*
+ * Activate SEV/SME memory encryption if supported/enabled. This needs to
+ * be done now, since this also includes setup of the SEV-SNP CPUID table,
+ * which needs to be done before any CPUID instructions are executed in
+ * subsequent code.
+ */
+ movq %rsi, %rdi
+ pushq %rsi
+ call sme_enable
+ popq %rsi
+#endif
+
+ /* Sanitize CPU configuration */
+ call verify_cpu
+
+ /*
+ * Perform pagetable fixups. Additionally, if SME is active, encrypt
+ * the kernel and retrieve the modifier (SME encryption mask if SME
+ * is active) to be added to the initial pgdir entry that will be
+ * programmed into CR3.
+ */
+ leaq _text(%rip), %rdi
+ pushq %rsi
+ call __startup_64
+ popq %rsi
+
+ /* Form the CR3 value being sure to include the CR3 modifier */
+ addq $(early_top_pgt - __START_KERNEL_map), %rax
+ jmp 1f
+SYM_CODE_END(startup_64)
+
+SYM_CODE_START(secondary_startup_64)
+ UNWIND_HINT_EMPTY
+ ANNOTATE_NOENDBR
+ /*
+ * At this point the CPU runs in 64bit mode CS.L = 1 CS.D = 0,
+ * and someone has loaded a mapped page table.
+ *
+ * %rsi holds a physical pointer to real_mode_data.
+ *
+ * We come here either from startup_64 (using physical addresses)
+ * or from trampoline.S (using virtual addresses).
+ *
+ * Using virtual addresses from trampoline.S removes the need
+ * to have any identity mapped pages in the kernel page table
+ * after the boot processor executes this code.
+ */
+
+ /* Sanitize CPU configuration */
+ call verify_cpu
+
+ /*
+ * The secondary_startup_64_no_verify entry point is only used by
+ * SEV-ES guests. In those guests the call to verify_cpu() would cause
+ * #VC exceptions which can not be handled at this stage of secondary
+ * CPU bringup.
+ *
+ * All non SEV-ES systems, especially Intel systems, need to execute
+ * verify_cpu() above to make sure NX is enabled.
+ */
+SYM_INNER_LABEL(secondary_startup_64_no_verify, SYM_L_GLOBAL)
+ UNWIND_HINT_EMPTY
+ ANNOTATE_NOENDBR
+
+ /*
+ * Retrieve the modifier (SME encryption mask if SME is active) to be
+ * added to the initial pgdir entry that will be programmed into CR3.
+ */
+#ifdef CONFIG_AMD_MEM_ENCRYPT
+ movq sme_me_mask, %rax
+#else
+ xorq %rax, %rax
+#endif
+
+ /* Form the CR3 value being sure to include the CR3 modifier */
+ addq $(init_top_pgt - __START_KERNEL_map), %rax
+1:
+
+#ifdef CONFIG_X86_MCE
+ /*
+ * Preserve CR4.MCE if the kernel will enable #MC support.
+ * Clearing MCE may fault in some environments (that also force #MC
+ * support). Any machine check that occurs before #MC support is fully
+ * configured will crash the system regardless of the CR4.MCE value set
+ * here.
+ */
+ movq %cr4, %rcx
+ andl $X86_CR4_MCE, %ecx
+#else
+ movl $0, %ecx
+#endif
+
+ /* Enable PAE mode, PGE and LA57 */
+ orl $(X86_CR4_PAE | X86_CR4_PGE), %ecx
+#ifdef CONFIG_X86_5LEVEL
+ testl $1, __pgtable_l5_enabled(%rip)
+ jz 1f
+ orl $X86_CR4_LA57, %ecx
+1:
+#endif
+ movq %rcx, %cr4
+
+ /* Setup early boot stage 4-/5-level pagetables. */
+ addq phys_base(%rip), %rax
+
+ /*
+ * For SEV guests: Verify that the C-bit is correct. A malicious
+ * hypervisor could lie about the C-bit position to perform a ROP
+ * attack on the guest by writing to the unencrypted stack and wait for
+ * the next RET instruction.
+ * %rsi carries pointer to realmode data and is callee-clobbered. Save
+ * and restore it.
+ */
+ pushq %rsi
+ movq %rax, %rdi
+ call sev_verify_cbit
+ popq %rsi
+
+ /*
+ * Switch to new page-table
+ *
+ * For the boot CPU this switches to early_top_pgt which still has the
+ * indentity mappings present. The secondary CPUs will switch to the
+ * init_top_pgt here, away from the trampoline_pgd and unmap the
+ * indentity mapped ranges.
+ */
+ movq %rax, %cr3
+
+ /*
+ * Do a global TLB flush after the CR3 switch to make sure the TLB
+ * entries from the identity mapping are flushed.
+ */
+ movq %cr4, %rcx
+ movq %rcx, %rax
+ xorq $X86_CR4_PGE, %rcx
+ movq %rcx, %cr4
+ movq %rax, %cr4
+
+ /* Ensure I am executing from virtual addresses */
+ movq $1f, %rax
+ ANNOTATE_RETPOLINE_SAFE
+ jmp *%rax
+1:
+ UNWIND_HINT_EMPTY
+ ANNOTATE_NOENDBR // above
+
+ /*
+ * We must switch to a new descriptor in kernel space for the GDT
+ * because soon the kernel won't have access anymore to the userspace
+ * 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 early_gdt_descr(%rip)
+
+ /* set up data segments */
+ xorl %eax,%eax
+ movl %eax,%ds
+ movl %eax,%ss
+ movl %eax,%es
+
+ /*
+ * We don't really need to load %fs or %gs, but load them anyway
+ * to kill any stale realmode selectors. This allows execution
+ * under VT hardware.
+ */
+ movl %eax,%fs
+ movl %eax,%gs
+
+ /* Set up %gs.
+ *
+ * The base of %gs always points to fixed_percpu_data. If the
+ * stack protector canary is enabled, it is located at %gs:40.
+ * Note that, on SMP, the boot cpu uses init data section until
+ * the per cpu areas are set up.
+ */
+ movl $MSR_GS_BASE,%ecx
+ movl initial_gs(%rip),%eax
+ movl initial_gs+4(%rip),%edx
+ wrmsr
+
+ /*
+ * Setup a boot time stack - Any secondary CPU will have lost its stack
+ * by now because the cr3-switch above unmaps the real-mode stack
+ */
+ movq initial_stack(%rip), %rsp
+
+ /* Setup and Load IDT */
+ pushq %rsi
+ call early_setup_idt
+ popq %rsi
+
+ /* Check if nx is implemented */
+ movl $0x80000001, %eax
+ cpuid
+ movl %edx,%edi
+
+ /* Setup EFER (Extended Feature Enable Register) */
+ movl $MSR_EFER, %ecx
+ rdmsr
+ /*
+ * Preserve current value of EFER for comparison and to skip
+ * EFER writes if no change was made (for TDX guest)
+ */
+ movl %eax, %edx
+ btsl $_EFER_SCE, %eax /* Enable System Call */
+ btl $20,%edi /* No Execute supported? */
+ jnc 1f
+ btsl $_EFER_NX, %eax
+ btsq $_PAGE_BIT_NX,early_pmd_flags(%rip)
+
+ /* Avoid writing EFER if no change was made (for TDX guest) */
+1: cmpl %edx, %eax
+ je 1f
+ xor %edx, %edx
+ wrmsr /* Make changes effective */
+1:
+ /* Setup cr0 */
+ movl $CR0_STATE, %eax
+ /* Make changes effective */
+ movq %rax, %cr0
+
+ /* zero EFLAGS after setting rsp */
+ pushq $0
+ popfq
+
+ /* rsi is pointer to real mode structure with interesting info.
+ pass it to C */
+ movq %rsi, %rdi
+
+.Ljump_to_C_code:
+ /*
+ * Jump to run C code and to be on a real kernel address.
+ * Since we are running on identity-mapped space we have to jump
+ * to the full 64bit address, this is only possible as indirect
+ * jump. In addition we need to ensure %cs is set so we make this
+ * a far return.
+ *
+ * Note: do not change to far jump indirect with 64bit offset.
+ *
+ * AMD does not support far jump indirect with 64bit offset.
+ * AMD64 Architecture Programmer's Manual, Volume 3: states only
+ * JMP FAR mem16:16 FF /5 Far jump indirect,
+ * with the target specified by a far pointer in memory.
+ * JMP FAR mem16:32 FF /5 Far jump indirect,
+ * with the target specified by a far pointer in memory.
+ *
+ * Intel64 does support 64bit offset.
+ * Software Developer Manual Vol 2: states:
+ * FF /5 JMP m16:16 Jump far, absolute indirect,
+ * address given in m16:16
+ * FF /5 JMP m16:32 Jump far, absolute indirect,
+ * address given in m16:32.
+ * REX.W + FF /5 JMP m16:64 Jump far, absolute indirect,
+ * address given in m16:64.
+ */
+ pushq $.Lafter_lret # put return address on stack for unwinder
+ xorl %ebp, %ebp # clear frame pointer
+ movq initial_code(%rip), %rax
+ pushq $__KERNEL_CS # set correct cs
+ pushq %rax # target address in negative space
+ lretq
+.Lafter_lret:
+ ANNOTATE_NOENDBR
+SYM_CODE_END(secondary_startup_64)
+
+#include "verify_cpu.S"
+#include "sev_verify_cbit.S"
+
+#ifdef CONFIG_HOTPLUG_CPU
+/*
+ * Boot CPU0 entry point. It's called from play_dead(). Everything has been set
+ * up already except stack. We just set up stack here. Then call
+ * start_secondary() via .Ljump_to_C_code.
+ */
+SYM_CODE_START(start_cpu0)
+ UNWIND_HINT_EMPTY
+ movq initial_stack(%rip), %rsp
+ jmp .Ljump_to_C_code
+SYM_CODE_END(start_cpu0)
+#endif
+
+#ifdef CONFIG_AMD_MEM_ENCRYPT
+/*
+ * VC Exception handler used during early boot when running on kernel
+ * addresses, but before the switch to the idt_table can be made.
+ * The early_idt_handler_array can't be used here because it calls into a lot
+ * of __init code and this handler is also used during CPU offlining/onlining.
+ * Therefore this handler ends up in the .text section so that it stays around
+ * when .init.text is freed.
+ */
+SYM_CODE_START_NOALIGN(vc_boot_ghcb)
+ UNWIND_HINT_IRET_REGS offset=8
+ ENDBR
+
+ ANNOTATE_UNRET_END
+
+ /* Build pt_regs */
+ PUSH_AND_CLEAR_REGS
+
+ /* Call C handler */
+ movq %rsp, %rdi
+ movq ORIG_RAX(%rsp), %rsi
+ movq initial_vc_handler(%rip), %rax
+ ANNOTATE_RETPOLINE_SAFE
+ call *%rax
+
+ /* Unwind pt_regs */
+ POP_REGS
+
+ /* Remove Error Code */
+ addq $8, %rsp
+
+ iretq
+SYM_CODE_END(vc_boot_ghcb)
+#endif
+
+ /* Both SMP bootup and ACPI suspend change these variables */
+ __REFDATA
+ .balign 8
+SYM_DATA(initial_code, .quad x86_64_start_kernel)
+SYM_DATA(initial_gs, .quad INIT_PER_CPU_VAR(fixed_percpu_data))
+#ifdef CONFIG_AMD_MEM_ENCRYPT
+SYM_DATA(initial_vc_handler, .quad handle_vc_boot_ghcb)
+#endif
+
+/*
+ * The FRAME_SIZE gap is a convention which helps the in-kernel unwinder
+ * reliably detect the end of the stack.
+ */
+SYM_DATA(initial_stack, .quad init_thread_union + THREAD_SIZE - FRAME_SIZE)
+ __FINITDATA
+
+ __INIT
+SYM_CODE_START(early_idt_handler_array)
+ i = 0
+ .rept NUM_EXCEPTION_VECTORS
+ .if ((EXCEPTION_ERRCODE_MASK >> i) & 1) == 0
+ UNWIND_HINT_IRET_REGS
+ ENDBR
+ pushq $0 # Dummy error code, to make stack frame uniform
+ .else
+ UNWIND_HINT_IRET_REGS offset=8
+ ENDBR
+ .endif
+ pushq $i # 72(%rsp) Vector number
+ jmp early_idt_handler_common
+ UNWIND_HINT_IRET_REGS
+ i = i + 1
+ .fill early_idt_handler_array + i*EARLY_IDT_HANDLER_SIZE - ., 1, 0xcc
+ .endr
+SYM_CODE_END(early_idt_handler_array)
+ ANNOTATE_NOENDBR // early_idt_handler_array[NUM_EXCEPTION_VECTORS]
+
+SYM_CODE_START_LOCAL(early_idt_handler_common)
+ UNWIND_HINT_IRET_REGS offset=16
+ ANNOTATE_UNRET_END
+ /*
+ * The stack is the hardware frame, an error code or zero, and the
+ * vector number.
+ */
+ cld
+
+ incl early_recursion_flag(%rip)
+
+ /* The vector number is currently in the pt_regs->di slot. */
+ pushq %rsi /* pt_regs->si */
+ movq 8(%rsp), %rsi /* RSI = vector number */
+ movq %rdi, 8(%rsp) /* pt_regs->di = RDI */
+ pushq %rdx /* pt_regs->dx */
+ pushq %rcx /* pt_regs->cx */
+ pushq %rax /* pt_regs->ax */
+ pushq %r8 /* pt_regs->r8 */
+ pushq %r9 /* pt_regs->r9 */
+ pushq %r10 /* pt_regs->r10 */
+ pushq %r11 /* pt_regs->r11 */
+ pushq %rbx /* pt_regs->bx */
+ pushq %rbp /* pt_regs->bp */
+ pushq %r12 /* pt_regs->r12 */
+ pushq %r13 /* pt_regs->r13 */
+ pushq %r14 /* pt_regs->r14 */
+ pushq %r15 /* pt_regs->r15 */
+ UNWIND_HINT_REGS
+
+ movq %rsp,%rdi /* RDI = pt_regs; RSI is already trapnr */
+ call do_early_exception
+
+ decl early_recursion_flag(%rip)
+ jmp restore_regs_and_return_to_kernel
+SYM_CODE_END(early_idt_handler_common)
+
+#ifdef CONFIG_AMD_MEM_ENCRYPT
+/*
+ * VC Exception handler used during very early boot. The
+ * early_idt_handler_array can't be used because it returns via the
+ * paravirtualized INTERRUPT_RETURN and pv-ops don't work that early.
+ *
+ * XXX it does, fix this.
+ *
+ * This handler will end up in the .init.text section and not be
+ * available to boot secondary CPUs.
+ */
+SYM_CODE_START_NOALIGN(vc_no_ghcb)
+ UNWIND_HINT_IRET_REGS offset=8
+ ENDBR
+
+ ANNOTATE_UNRET_END
+
+ /* Build pt_regs */
+ PUSH_AND_CLEAR_REGS
+
+ /* Call C handler */
+ movq %rsp, %rdi
+ movq ORIG_RAX(%rsp), %rsi
+ call do_vc_no_ghcb
+
+ /* Unwind pt_regs */
+ POP_REGS
+
+ /* Remove Error Code */
+ addq $8, %rsp
+
+ /* Pure iret required here - don't use INTERRUPT_RETURN */
+ iretq
+SYM_CODE_END(vc_no_ghcb)
+#endif
+
+#define SYM_DATA_START_PAGE_ALIGNED(name) \
+ SYM_START(name, SYM_L_GLOBAL, .balign PAGE_SIZE)
+
+#ifdef CONFIG_PAGE_TABLE_ISOLATION
+/*
+ * Each PGD needs to be 8k long and 8k aligned. We do not
+ * ever go out to userspace with these, so we do not
+ * strictly *need* the second page, but this allows us to
+ * have a single set_pgd() implementation that does not
+ * need to worry about whether it has 4k or 8k to work
+ * with.
+ *
+ * This ensures PGDs are 8k long:
+ */
+#define PTI_USER_PGD_FILL 512
+/* This ensures they are 8k-aligned: */
+#define SYM_DATA_START_PTI_ALIGNED(name) \
+ SYM_START(name, SYM_L_GLOBAL, .balign 2 * PAGE_SIZE)
+#else
+#define SYM_DATA_START_PTI_ALIGNED(name) \
+ SYM_DATA_START_PAGE_ALIGNED(name)
+#define PTI_USER_PGD_FILL 0
+#endif
+
+/* Automate the creation of 1 to 1 mapping pmd entries */
+#define PMDS(START, PERM, COUNT) \
+ i = 0 ; \
+ .rept (COUNT) ; \
+ .quad (START) + (i << PMD_SHIFT) + (PERM) ; \
+ i = i + 1 ; \
+ .endr
+
+ __INITDATA
+ .balign 4
+
+SYM_DATA_START_PTI_ALIGNED(early_top_pgt)
+ .fill 512,8,0
+ .fill PTI_USER_PGD_FILL,8,0
+SYM_DATA_END(early_top_pgt)
+
+SYM_DATA_START_PAGE_ALIGNED(early_dynamic_pgts)
+ .fill 512*EARLY_DYNAMIC_PAGE_TABLES,8,0
+SYM_DATA_END(early_dynamic_pgts)
+
+SYM_DATA(early_recursion_flag, .long 0)
+
+ .data
+
+#if defined(CONFIG_XEN_PV) || defined(CONFIG_PVH)
+SYM_DATA_START_PTI_ALIGNED(init_top_pgt)
+ .quad level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE_NOENC
+ .org init_top_pgt + L4_PAGE_OFFSET*8, 0
+ .quad level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE_NOENC
+ .org init_top_pgt + L4_START_KERNEL*8, 0
+ /* (2^48-(2*1024*1024*1024))/(2^39) = 511 */
+ .quad level3_kernel_pgt - __START_KERNEL_map + _PAGE_TABLE_NOENC
+ .fill PTI_USER_PGD_FILL,8,0
+SYM_DATA_END(init_top_pgt)
+
+SYM_DATA_START_PAGE_ALIGNED(level3_ident_pgt)
+ .quad level2_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE_NOENC
+ .fill 511, 8, 0
+SYM_DATA_END(level3_ident_pgt)
+SYM_DATA_START_PAGE_ALIGNED(level2_ident_pgt)
+ /*
+ * Since I easily can, map the first 1G.
+ * Don't set NX because code runs from these pages.
+ *
+ * Note: This sets _PAGE_GLOBAL despite whether
+ * the CPU supports it or it is enabled. But,
+ * the CPU should ignore the bit.
+ */
+ PMDS(0, __PAGE_KERNEL_IDENT_LARGE_EXEC, PTRS_PER_PMD)
+SYM_DATA_END(level2_ident_pgt)
+#else
+SYM_DATA_START_PTI_ALIGNED(init_top_pgt)
+ .fill 512,8,0
+ .fill PTI_USER_PGD_FILL,8,0
+SYM_DATA_END(init_top_pgt)
+#endif
+
+#ifdef CONFIG_X86_5LEVEL
+SYM_DATA_START_PAGE_ALIGNED(level4_kernel_pgt)
+ .fill 511,8,0
+ .quad level3_kernel_pgt - __START_KERNEL_map + _PAGE_TABLE_NOENC
+SYM_DATA_END(level4_kernel_pgt)
+#endif
+
+SYM_DATA_START_PAGE_ALIGNED(level3_kernel_pgt)
+ .fill L3_START_KERNEL,8,0
+ /* (2^48-(2*1024*1024*1024)-((2^39)*511))/(2^30) = 510 */
+ .quad level2_kernel_pgt - __START_KERNEL_map + _KERNPG_TABLE_NOENC
+ .quad level2_fixmap_pgt - __START_KERNEL_map + _PAGE_TABLE_NOENC
+SYM_DATA_END(level3_kernel_pgt)
+
+SYM_DATA_START_PAGE_ALIGNED(level2_kernel_pgt)
+ /*
+ * Kernel high mapping.
+ *
+ * The kernel code+data+bss must be located below KERNEL_IMAGE_SIZE in
+ * virtual address space, which is 1 GiB if RANDOMIZE_BASE is enabled,
+ * 512 MiB otherwise.
+ *
+ * (NOTE: after that starts the module area, see MODULES_VADDR.)
+ *
+ * This table is eventually used by the kernel during normal runtime.
+ * Care must be taken to clear out undesired bits later, like _PAGE_RW
+ * or _PAGE_GLOBAL in some cases.
+ */
+ PMDS(0, __PAGE_KERNEL_LARGE_EXEC, KERNEL_IMAGE_SIZE/PMD_SIZE)
+SYM_DATA_END(level2_kernel_pgt)
+
+SYM_DATA_START_PAGE_ALIGNED(level2_fixmap_pgt)
+ .fill (512 - 4 - FIXMAP_PMD_NUM),8,0
+ pgtno = 0
+ .rept (FIXMAP_PMD_NUM)
+ .quad level1_fixmap_pgt + (pgtno << PAGE_SHIFT) - __START_KERNEL_map \
+ + _PAGE_TABLE_NOENC;
+ pgtno = pgtno + 1
+ .endr
+ /* 6 MB reserved space + a 2MB hole */
+ .fill 4,8,0
+SYM_DATA_END(level2_fixmap_pgt)
+
+SYM_DATA_START_PAGE_ALIGNED(level1_fixmap_pgt)
+ .rept (FIXMAP_PMD_NUM)
+ .fill 512,8,0
+ .endr
+SYM_DATA_END(level1_fixmap_pgt)
+
+#undef PMDS
+
+ .data
+ .align 16
+
+SYM_DATA(early_gdt_descr, .word GDT_ENTRIES*8-1)
+SYM_DATA_LOCAL(early_gdt_descr_base, .quad INIT_PER_CPU_VAR(gdt_page))
+
+ .align 16
+/* This must match the first entry in level2_kernel_pgt */
+SYM_DATA(phys_base, .quad 0x0)
+EXPORT_SYMBOL(phys_base)
+
+#include "../../x86/xen/xen-head.S"
+
+ __PAGE_ALIGNED_BSS
+SYM_DATA_START_PAGE_ALIGNED(empty_zero_page)
+ .skip PAGE_SIZE
+SYM_DATA_END(empty_zero_page)
+EXPORT_SYMBOL(empty_zero_page)
+