[PATCH] kexec: x86 kexec core
This is the i386 implementation of kexec.
Signed-off-by: Eric Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/i386/kernel/relocate_kernel.S b/arch/i386/kernel/relocate_kernel.S
new file mode 100644
index 0000000..d312616
--- /dev/null
+++ b/arch/i386/kernel/relocate_kernel.S
@@ -0,0 +1,120 @@
+/*
+ * relocate_kernel.S - put the kernel image in place to boot
+ * Copyright (C) 2002-2004 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>
+
+ /*
+ * Must be relocatable PIC code callable as a C function, that once
+ * it starts can not use the previous processes stack.
+ */
+ .globl relocate_new_kernel
+relocate_new_kernel:
+ /* read the arguments and say goodbye to the stack */
+ movl 4(%esp), %ebx /* page_list */
+ movl 8(%esp), %ebp /* reboot_code_buffer */
+ movl 12(%esp), %edx /* start address */
+ movl 16(%esp), %ecx /* cpu_has_pae */
+
+ /* zero out flags, and disable interrupts */
+ pushl $0
+ popfl
+
+ /* set a new stack at the bottom of our page... */
+ lea 4096(%ebp), %esp
+
+ /* store the parameters back on the stack */
+ pushl %edx /* store the start address */
+
+ /* Set cr0 to a known state:
+ * 31 0 == Paging disabled
+ * 18 0 == Alignment check disabled
+ * 16 0 == Write protect disabled
+ * 3 0 == No task switch
+ * 2 0 == Don't do FP software emulation.
+ * 0 1 == Proctected mode enabled
+ */
+ movl %cr0, %eax
+ andl $~((1<<31)|(1<<18)|(1<<16)|(1<<3)|(1<<2)), %eax
+ orl $(1<<0), %eax
+ movl %eax, %cr0
+
+ /* clear cr4 if applicable */
+ testl %ecx, %ecx
+ jz 1f
+ /* Set cr4 to a known state:
+ * Setting everything to zero seems safe.
+ */
+ movl %cr4, %eax
+ andl $0, %eax
+ movl %eax, %cr4
+
+ jmp 1f
+1:
+
+ /* Flush the TLB (needed?) */
+ xorl %eax, %eax
+ movl %eax, %cr3
+
+ /* Do the copies */
+ movl %ebx, %ecx
+ jmp 1f
+
+0: /* top, read another word from the indirection page */
+ movl (%ebx), %ecx
+ addl $4, %ebx
+1:
+ testl $0x1, %ecx /* is it a destination page */
+ jz 2f
+ movl %ecx, %edi
+ andl $0xfffff000, %edi
+ jmp 0b
+2:
+ testl $0x2, %ecx /* is it an indirection page */
+ jz 2f
+ movl %ecx, %ebx
+ andl $0xfffff000, %ebx
+ jmp 0b
+2:
+ testl $0x4, %ecx /* is it the done indicator */
+ jz 2f
+ jmp 3f
+2:
+ testl $0x8, %ecx /* is it the source indicator */
+ jz 0b /* Ignore it otherwise */
+ movl %ecx, %esi /* For every source page do a copy */
+ andl $0xfffff000, %esi
+
+ movl $1024, %ecx
+ rep ; movsl
+ jmp 0b
+
+3:
+
+ /* To be certain of avoiding problems with self-modifying code
+ * I need to execute a serializing instruction here.
+ * So I flush the TLB, it's handy, and not processor dependent.
+ */
+ xorl %eax, %eax
+ movl %eax, %cr3
+
+ /* set all of the registers to known values */
+ /* leave %esp alone */
+
+ xorl %eax, %eax
+ xorl %ebx, %ebx
+ xorl %ecx, %ecx
+ xorl %edx, %edx
+ xorl %esi, %esi
+ xorl %edi, %edi
+ xorl %ebp, %ebp
+ ret
+relocate_new_kernel_end:
+
+ .globl relocate_new_kernel_size
+relocate_new_kernel_size:
+ .long relocate_new_kernel_end - relocate_new_kernel