Initial import

1 files changed, 268 insertions, 0 deletions

diff --git a/arch/x86/kernel/relocate_kernel_64.S b/arch/x86/kernel/relocate_kernel_64.S
new file mode 100644
index 000000000..98111b38e
--- /dev/null
+++ b/arch/x86/kernel/relocate_kernel_64.S
@@ -0,0 +1,268 @@
+/*
+ * 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