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- /*
- * relocate_kernel.S - put the kernel image in place to boot
- * Copyright (C) 2002-2005 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_types.h>
- #include <asm/kexec.h>
- #include <asm/processor-flags.h>
- #include <asm/pgtable_types.h>
- /*
- * Must be relocatable PIC code callable as a C function
- */
- #define PTR(x) (x << 3)
- #define PAGE_ATTR (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY)
- /*
- * control_page + KEXEC_CONTROL_CODE_MAX_SIZE
- * ~ control_page + PAGE_SIZE are used as data storage and stack for
- * jumping back
- */
- #define DATA(offset) (KEXEC_CONTROL_CODE_MAX_SIZE+(offset))
- /* Minimal CPU state */
- #define RSP DATA(0x0)
- #define CR0 DATA(0x8)
- #define CR3 DATA(0x10)
- #define CR4 DATA(0x18)
- /* other data */
- #define CP_PA_TABLE_PAGE DATA(0x20)
- #define CP_PA_SWAP_PAGE DATA(0x28)
- #define CP_PA_BACKUP_PAGES_MAP DATA(0x30)
- .text
- .align PAGE_SIZE
- .code64
- .globl relocate_kernel
- relocate_kernel:
- /*
- * %rdi indirection_page
- * %rsi page_list
- * %rdx start address
- * %rcx preserve_context
- */
- /* Save the CPU context, used for jumping back */
- pushq %rbx
- pushq %rbp
- pushq %r12
- pushq %r13
- pushq %r14
- pushq %r15
- pushf
- movq PTR(VA_CONTROL_PAGE)(%rsi), %r11
- movq %rsp, RSP(%r11)
- movq %cr0, %rax
- movq %rax, CR0(%r11)
- movq %cr3, %rax
- movq %rax, CR3(%r11)
- movq %cr4, %rax
- movq %rax, CR4(%r11)
- /* zero out flags, and disable interrupts */
- pushq $0
- popfq
- /*
- * get physical address of control page now
- * this is impossible after page table switch
- */
- movq PTR(PA_CONTROL_PAGE)(%rsi), %r8
- /* get physical address of page table now too */
- movq PTR(PA_TABLE_PAGE)(%rsi), %r9
- /* get physical address of swap page now */
- movq PTR(PA_SWAP_PAGE)(%rsi), %r10
- /* save some information for jumping back */
- movq %r9, CP_PA_TABLE_PAGE(%r11)
- movq %r10, CP_PA_SWAP_PAGE(%r11)
- movq %rdi, CP_PA_BACKUP_PAGES_MAP(%r11)
- /* Switch to the identity mapped page tables */
- movq %r9, %cr3
- /* setup a new stack at the end of the physical control page */
- lea PAGE_SIZE(%r8), %rsp
- /* jump to identity mapped page */
- addq $(identity_mapped - relocate_kernel), %r8
- pushq %r8
- ret
- identity_mapped:
- /* set return address to 0 if not preserving context */
- pushq $0
- /* store the start address on the stack */
- pushq %rdx
- /*
- * Set cr0 to a known state:
- * - Paging enabled
- * - Alignment check disabled
- * - Write protect disabled
- * - No task switch
- * - Don't do FP software emulation.
- * - Proctected mode enabled
- */
- movq %cr0, %rax
- andq $~(X86_CR0_AM | X86_CR0_WP | X86_CR0_TS | X86_CR0_EM), %rax
- orl $(X86_CR0_PG | X86_CR0_PE), %eax
- movq %rax, %cr0
- /*
- * Set cr4 to a known state:
- * - physical address extension enabled
- */
- movl $X86_CR4_PAE, %eax
- movq %rax, %cr4
- jmp 1f
- 1:
- /* Flush the TLB (needed?) */
- movq %r9, %cr3
- movq %rcx, %r11
- call swap_pages
- /*
- * To be certain of avoiding problems with self-modifying code
- * I need to execute a serializing instruction here.
- * So I flush the TLB by reloading %cr3 here, it's handy,
- * and not processor dependent.
- */
- movq %cr3, %rax
- movq %rax, %cr3
- /*
- * set all of the registers to known values
- * leave %rsp alone
- */
- testq %r11, %r11
- jnz 1f
- xorl %eax, %eax
- xorl %ebx, %ebx
- xorl %ecx, %ecx
- xorl %edx, %edx
- xorl %esi, %esi
- xorl %edi, %edi
- xorl %ebp, %ebp
- xorl %r8d, %r8d
- xorl %r9d, %r9d
- xorl %r10d, %r10d
- xorl %r11d, %r11d
- xorl %r12d, %r12d
- xorl %r13d, %r13d
- xorl %r14d, %r14d
- xorl %r15d, %r15d
- ret
- 1:
- popq %rdx
- leaq PAGE_SIZE(%r10), %rsp
- call *%rdx
- /* get the re-entry point of the peer system */
- movq 0(%rsp), %rbp
- call 1f
- 1:
- popq %r8
- subq $(1b - relocate_kernel), %r8
- movq CP_PA_SWAP_PAGE(%r8), %r10
- movq CP_PA_BACKUP_PAGES_MAP(%r8), %rdi
- movq CP_PA_TABLE_PAGE(%r8), %rax
- movq %rax, %cr3
- lea PAGE_SIZE(%r8), %rsp
- call swap_pages
- movq $virtual_mapped, %rax
- pushq %rax
- ret
- virtual_mapped:
- movq RSP(%r8), %rsp
- movq CR4(%r8), %rax
- movq %rax, %cr4
- movq CR3(%r8), %rax
- movq CR0(%r8), %r8
- movq %rax, %cr3
- movq %r8, %cr0
- movq %rbp, %rax
- popf
- popq %r15
- popq %r14
- popq %r13
- popq %r12
- popq %rbp
- popq %rbx
- ret
- /* Do the copies */
- swap_pages:
- movq %rdi, %rcx /* Put the page_list in %rcx */
- xorl %edi, %edi
- xorl %esi, %esi
- jmp 1f
- 0: /* top, read another word for the indirection page */
- movq (%rbx), %rcx
- addq $8, %rbx
- 1:
- testb $0x1, %cl /* is it a destination page? */
- jz 2f
- movq %rcx, %rdi
- andq $0xfffffffffffff000, %rdi
- jmp 0b
- 2:
- testb $0x2, %cl /* is it an indirection page? */
- jz 2f
- movq %rcx, %rbx
- andq $0xfffffffffffff000, %rbx
- jmp 0b
- 2:
- testb $0x4, %cl /* is it the done indicator? */
- jz 2f
- jmp 3f
- 2:
- testb $0x8, %cl /* is it the source indicator? */
- jz 0b /* Ignore it otherwise */
- movq %rcx, %rsi /* For ever source page do a copy */
- andq $0xfffffffffffff000, %rsi
- movq %rdi, %rdx
- movq %rsi, %rax
- movq %r10, %rdi
- movl $512, %ecx
- rep ; movsq
- movq %rax, %rdi
- movq %rdx, %rsi
- movl $512, %ecx
- rep ; movsq
- movq %rdx, %rdi
- movq %r10, %rsi
- movl $512, %ecx
- rep ; movsq
- lea PAGE_SIZE(%rax), %rsi
- jmp 0b
- 3:
- ret
- .globl kexec_control_code_size
- .set kexec_control_code_size, . - relocate_kernel
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