[PATCH] i386: remove default_ldt, and simplify ldt-setting.

This patch removes the default_ldt[] array, as it has been unused since
iBCS stopped being supported.  This means it is now possible to actually
set an empty LDT segment.

In order to deal with this, the set_ldt_desc/load_LDT pair has been
replaced with a single set_ldt() operation which is responsible for both
setting up the LDT descriptor in the GDT, and reloading the LDT register.
If there are no LDT entries, the LDT register is loaded with a NULL
descriptor.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@suse.de>
Acked-by: Zachary Amsden <zach@vmware.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>

2 files changed, 1 insertions, 6 deletions

diff --git a/arch/i386/kernel/ldt.c b/arch/i386/kernel/ldt.c
index 445211eb2d57..b410e5fb034f 100644
--- a/arch/i386/kernel/ldt.c
+++ b/arch/i386/kernel/ldt.c
@@ -160,16 +160,14 @@ static int read_default_ldt(void __user * ptr, unsigned long bytecount)
 {
         int err;
         unsigned long size;
-        void *address;
 
         err = 0;
-        address = &default_ldt[0];
         size = 5*sizeof(struct desc_struct);
         if (size > bytecount)
                 size = bytecount;
 
         err = size;
-        if (copy_to_user(ptr, address, size))
+        if (clear_user(ptr, size))
                 err = -EFAULT;
 
         return err;
diff --git a/arch/i386/kernel/traps.c b/arch/i386/kernel/traps.c
index 48ebfab661b7..56655ea8d98f 100644
--- a/arch/i386/kernel/traps.c
+++ b/arch/i386/kernel/traps.c
@@ -61,9 +61,6 @@ int panic_on_unrecovered_nmi;
 
 asmlinkage int system_call(void);
 
-struct desc_struct default_ldt[] = { { 0, 0 }, { 0, 0 }, { 0, 0 },
-                { 0, 0 }, { 0, 0 } };
-
 /* Do we ignore FPU interrupts ? */
 char ignore_fpu_irq = 0;