x86: setup segment registers before percpu areas
The base of the percpu area is stored in the %gs base, and writing
to %gs destroys it. Move setup_segments earlier, before the %gs
base is written, and keep setup_percpu_area close so that the base
is updated close to the selector.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/x86/cstart.S b/x86/cstart.S
index 5288252..409cb00 100644
--- a/x86/cstart.S
+++ b/x86/cstart.S
@@ -109,7 +109,11 @@
.globl start
start:
+ lgdtl gdt32_descr
+ setup_segments
mov $stacktop, %esp
+ setup_percpu_area
+
push %ebx
call setup_multiboot
addl $4, %esp
@@ -117,14 +121,10 @@
mov mb_cmdline(%ebx), %eax
mov %eax, __args
call __setup_args
- setup_percpu_area
call prepare_32
jmpl $8, $start32
prepare_32:
- lgdtl gdt32_descr
- setup_segments
-
mov %cr4, %eax
bts $4, %eax // pse
mov %eax, %cr4
