[PATCH] x86-64: cleanup segments

Move __KERNEL32_CS up into the unused gdt entry.  __KERNEL32_CS is
used when entering the kernel so putting it first is useful when
trying to keep boot gdt sizes to a minimum.

Set the accessed bit on all gdt entries.  We don't care
so there is no need for the cpu to burn the extra cycles,
and it potentially allows the pages to be immutable.  Plus
it is confusing when debugging and your gdt entries mysteriously
change.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andi Kleen <ak@suse.de>

2 files changed, 7 insertions, 7 deletions

diff --git a/arch/x86_64/kernel/head.S b/arch/x86_64/kernel/head.S
index 23b45e79a27c..2b2e2c51e532 100644
--- a/arch/x86_64/kernel/head.S
+++ b/arch/x86_64/kernel/head.S
@@ -362,13 +362,13 @@ gdt:
         
 ENTRY(cpu_gdt_table)
         .quad   0x0000000000000000      /* NULL descriptor */
+        .quad   0x00cf9b000000ffff      /* __KERNEL32_CS */
+        .quad   0x00af9b000000ffff      /* __KERNEL_CS */
+        .quad   0x00cf93000000ffff      /* __KERNEL_DS */
+        .quad   0x00cffb000000ffff      /* __USER32_CS */
+        .quad   0x00cff3000000ffff      /* __USER_DS, __USER32_DS  */
+        .quad   0x00affb000000ffff      /* __USER_CS */
         .quad   0x0                     /* unused */
-        .quad   0x00af9a000000ffff      /* __KERNEL_CS */
-        .quad   0x00cf92000000ffff      /* __KERNEL_DS */
-        .quad   0x00cffa000000ffff      /* __USER32_CS */
-        .quad   0x00cff2000000ffff      /* __USER_DS, __USER32_DS  */           
-        .quad   0x00affa000000ffff      /* __USER_CS */
-        .quad   0x00cf9a000000ffff      /* __KERNEL32_CS */
         .quad   0,0                     /* TSS */
         .quad   0,0                     /* LDT */
         .quad   0,0,0                   /* three TLS descriptors */ 
diff --git a/include/asm-x86_64/segment.h b/include/asm-x86_64/segment.h
index 334ddcdd8f92..adf2bf1e187c 100644
--- a/include/asm-x86_64/segment.h
+++ b/include/asm-x86_64/segment.h
@@ -6,7 +6,7 @@
 #define __KERNEL_CS     0x10
 #define __KERNEL_DS     0x18
 
-#define __KERNEL32_CS   0x38
+#define __KERNEL32_CS   0x08
 
 /* 
  * we cannot use the same code segment descriptor for user and kernel