grub/grub-core/lib/i386/xen/relocator.S
Juergen Gross b67a95ecad xen: modify page table construction
Modify the page table construction to allow multiple virtual regions
to be mapped. This is done as preparation for removing the p2m list
from the initial kernel mapping in order to support huge pv domains.

This allows a cleaner approach for mapping the relocator page by
using this capability.

The interface to the assembler level of the relocator has to be changed
in order to be able to process multiple page table areas.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2016-10-27 16:22:06 +02:00

165 lines
4 KiB
ArmAsm

/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2013 Free Software Foundation, Inc.
*
* GRUB is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* GRUB is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
#include <grub/i386/memory.h>
#include <grub/i386/types.h>
#include <grub/symbol.h>
#include <grub/xen.h>
.p2align 4 /* force 16-byte alignment */
VARIABLE(grub_relocator_xen_remap_start)
LOCAL(base):
/* Remap the remapper to it's new address. */
/* mov imm32, %ebx - %ebx: new virtual address of remapper */
.byte 0xbb
VARIABLE(grub_relocator_xen_remapper_virt)
.long 0
/* mov imm32, %ecx - %ecx: low part of page table entry */
.byte 0xb9
VARIABLE(grub_relocator_xen_remapper_map)
.long 0
/* mov imm32, %edx - %edx: high part of page table entry */
.byte 0xba
VARIABLE(grub_relocator_xen_remapper_map_high)
.long 0
movl %ebx, %ebp /* %ebx is clobbered by hypercall */
movl $UVMF_INVLPG, %esi /* esi: flags (inv. single entry) */
movl $__HYPERVISOR_update_va_mapping, %eax
int $0x82
movl %ebp, %ebx
addl $(LOCAL(cont) - LOCAL(base)), %ebx
jmp *%ebx /* Continue with new virtual address */
LOCAL(cont):
/* Modify mappings of new page tables to be read-only. */
/* mov imm32, %eax */
.byte 0xb8
VARIABLE(grub_relocator_xen_paging_areas_addr)
.long 0
movl %eax, %ebx
1:
movl 0(%ebx), %ebp /* Get start pfn of the current area */
movl GRUB_TARGET_SIZEOF_LONG(%ebx), %ecx /* Get # of pg tables */
testl %ecx, %ecx /* 0 -> last area reached */
jz 3f
addl $(2 * GRUB_TARGET_SIZEOF_LONG), %ebx
movl %ebx, %esp /* Save current area pointer */
2:
movl %ecx, %edi
/* mov imm32, %eax */
.byte 0xb8
VARIABLE(grub_relocator_xen_mfn_list)
.long 0
movl 0(%eax, %ebp, 4), %ecx /* mfn */
movl %ebp, %ebx
shll $PAGE_SHIFT, %ebx /* virtual address (1:1 mapping) */
movl %ecx, %edx
shll $PAGE_SHIFT, %ecx /* prepare pte low part */
shrl $(32 - PAGE_SHIFT), %edx /* pte high part */
orl $(GRUB_PAGE_PRESENT | GRUB_PAGE_USER), %ecx /* pte low */
movl $UVMF_INVLPG, %esi
movl $__HYPERVISOR_update_va_mapping, %eax
int $0x82 /* parameters: eax, ebx, ecx, edx, esi */
incl %ebp /* next pfn */
movl %edi, %ecx
loop 2b
mov %esp, %ebx /* restore area poniter */
jmp 1b
3:
/* Switch page tables: pin new L3 pt, load cr3, unpin old L3. */
/* mov imm32, %ebx */
.byte 0xbb
VARIABLE(grub_relocator_xen_mmu_op_addr)
.long 0
movl $3, %ecx /* 3 mmu ops */
movl $0, %edx /* pdone (not used) */
movl $DOMID_SELF, %esi
movl $__HYPERVISOR_mmuext_op, %eax
int $0x82
/* Continue in virtual kernel mapping. */
/* mov imm32, %eax */
.byte 0xb8
VARIABLE(grub_relocator_xen_remap_continue)
.long 0
jmp *%eax
VARIABLE(grub_relocator_xen_paging_areas)
.long 0, 0, 0, 0, 0, 0, 0, 0
VARIABLE(grub_relocator_xen_mmu_op)
.space 256
VARIABLE(grub_relocator_xen_remap_end)
VARIABLE(grub_relocator_xen_start)
/* Unmap old remapper area. */
/* mov imm32, %eax */
.byte 0xb8
VARIABLE(grub_relocator_xen_remapper_virt2)
.long 0
movl %eax, %edi
xorl %ecx, %ecx /* Invalid pte */
xorl %edx, %edx
movl $UVMF_INVLPG, %esi
movl $__HYPERVISOR_update_va_mapping, %eax
int $0x82
/* Prepare registers for starting kernel. */
/* mov imm32, %eax */
.byte 0xb8
VARIABLE(grub_relocator_xen_stack)
.long 0
movl %eax, %esp
/* mov imm32, %eax */
.byte 0xb8
VARIABLE(grub_relocator_xen_start_info)
.long 0
movl %eax, %esi
cld
/* mov imm32, %eax */
.byte 0xb8
VARIABLE(grub_relocator_xen_entry_point)
.long 0
/* Now start the new kernel. */
jmp *%eax
VARIABLE(grub_relocator_xen_end)