* 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>
- *
- * $Id: head.S,v 1.49 2002/03/19 17:39:25 ak Exp $
*/
*/
lgdt cpu_gdt_descr
+ /* set up data segments. actually 0 would do too */
+ movl $__KERNEL_DS,%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
+
/*
* Setup up a dummy PDA. this is just for some early bootup code
* that does in_interrupt()
shrq $32,%rdx
wrmsr
- /* set up data segments. actually 0 would do too */
- movl $__KERNEL_DS,%eax
- movl %eax,%ds
- movl %eax,%ss
- movl %eax,%es
-
/* esi is pointer to real mode structure with interesting info.
pass it to C */
movl %esi, %edi
/* Finally jump to run C code and to be on 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
+ * 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.
*/
movq initial_code(%rip),%rax
- jmp *%rax
+ pushq $0 # fake return address to stop unwinder
+ pushq $__KERNEL_CS # set correct cs
+ pushq %rax # target address in negative space
+ lretq
/* SMP bootup changes these two */
.align 8
.quad 0,0 /* TSS */
.quad 0,0 /* LDT */
.quad 0,0,0 /* three TLS descriptors */
- .quad 0 /* unused */
+ .quad 0x0000f40000000000 /* node/CPU stored in limit */
gdt_end:
/* asm/segment.h:GDT_ENTRIES must match this */
/* This should be a multiple of the cache line size */