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authorZachary Amsden <zach@vmware.com>2007-02-13 13:26:24 +0100
committerAndi Kleen <andi@basil.nowhere.org>2007-02-13 13:26:24 +0100
commitffb6017563aa15f9a8cff9a30b861d42c2695894 (patch)
tree7697613cc885f46827e18f3c285879c15c353b04 /arch/x86_64
parent9a11ff68273f440b1d33fcc4d550ffc881e6a0b4 (diff)
[PATCH] x86-64: x86_64 - Fix FS/GS registers for VT execution
Initialize FS and GS to __KERNEL_DS as well. The actual value of them is not important, but it is important to reload them in protected mode. At this time, they still retain the real mode values from initial boot. VT disallows execution of code under such conditions, which means hardware virtualization can not be used to boot the kernel on Intel platforms, making the boot time painfully slow. This requires moving the GS load before the load of GS_BASE, so just move all the segments loads there to keep them together in the code. Signed-off-by: Zachary Amsden <zach@vmware.com> Signed-off-by: Andi Kleen <ak@suse.de>
Diffstat (limited to 'arch/x86_64')
-rw-r--r--arch/x86_64/kernel/head.S20
1 files changed, 14 insertions, 6 deletions
diff --git a/arch/x86_64/kernel/head.S b/arch/x86_64/kernel/head.S
index 1e6f8087067..598a4d0351f 100644
--- a/arch/x86_64/kernel/head.S
+++ b/arch/x86_64/kernel/head.S
@@ -163,6 +163,20 @@ startup_64:
*/
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()
@@ -173,12 +187,6 @@ startup_64:
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