4 files changed, 22 insertions, 39 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;
 
diff --git a/include/asm-i386/desc.h b/include/asm-i386/desc.h
index 5874ef119ffd..a0398f780ca1 100644
--- a/include/asm-i386/desc.h
+++ b/include/asm-i386/desc.h
@@ -33,11 +33,6 @@ static inline struct desc_struct *get_cpu_gdt_table(unsigned int cpu)
         return (struct desc_struct *)per_cpu(cpu_gdt_descr, cpu).address;
 }
 
-/*
- * This is the ldt that every process will get unless we need
- * something other than this.
- */
-extern struct desc_struct default_ldt[];
 extern struct desc_struct idt_table[];
 extern void set_intr_gate(unsigned int irq, void * addr);
 
@@ -65,7 +60,6 @@ static inline void pack_gate(__u32 *a, __u32 *b,
 #define DESCTYPE_S      0x10    /* !system */
 
 #define load_TR_desc() __asm__ __volatile__("ltr %w0"::"q" (GDT_ENTRY_TSS*8))
-#define load_LDT_desc() __asm__ __volatile__("lldt %w0"::"q" (GDT_ENTRY_LDT*8))
 
 #define load_gdt(dtr) __asm__ __volatile("lgdt %0"::"m" (*dtr))
 #define load_idt(dtr) __asm__ __volatile("lidt %0"::"m" (*dtr))
@@ -115,13 +109,20 @@ static inline void __set_tss_desc(unsigned int cpu, unsigned int entry, const vo
         write_gdt_entry(get_cpu_gdt_table(cpu), entry, a, b);
 }
 
-static inline void set_ldt_desc(unsigned int cpu, void *addr, unsigned int entries)
+static inline void set_ldt(void *addr, unsigned int entries)
 {
-        __u32 a, b;
-        pack_descriptor(&a, &b, (unsigned long)addr,
-                        entries * sizeof(struct desc_struct) - 1,
-                        DESCTYPE_LDT, 0);
-        write_gdt_entry(get_cpu_gdt_table(cpu), GDT_ENTRY_LDT, a, b);
+        if (likely(entries == 0))
+                __asm__ __volatile__("lldt %w0"::"q" (0));
+        else {
+                unsigned cpu = smp_processor_id();
+                __u32 a, b;
+
+                pack_descriptor(&a, &b, (unsigned long)addr,
+                                entries * sizeof(struct desc_struct) - 1,
+                                DESCTYPE_LDT, 0);
+                write_gdt_entry(get_cpu_gdt_table(cpu), GDT_ENTRY_LDT, a, b);
+                __asm__ __volatile__("lldt %w0"::"q" (GDT_ENTRY_LDT*8));
+        }
 }
 
 #define set_tss_desc(cpu,addr) __set_tss_desc(cpu, GDT_ENTRY_TSS, addr)
@@ -153,35 +154,22 @@ static inline void set_ldt_desc(unsigned int cpu, void *addr, unsigned int entri
 
 static inline void clear_LDT(void)
 {
-        int cpu = get_cpu();
-
-        set_ldt_desc(cpu, &default_ldt[0], 5);
-        load_LDT_desc();
-        put_cpu();
+        set_ldt(NULL, 0);
 }
 
 /*
  * load one particular LDT into the current CPU
  */
-static inline void load_LDT_nolock(mm_context_t *pc, int cpu)
+static inline void load_LDT_nolock(mm_context_t *pc)
 {
-        void *segments = pc->ldt;
-        int count = pc->size;
-
-        if (likely(!count)) {
-                segments = &default_ldt[0];
-                count = 5;
-        }
-                
-        set_ldt_desc(cpu, segments, count);
-        load_LDT_desc();
+        set_ldt(pc->ldt, pc->size);
 }
 
 static inline void load_LDT(mm_context_t *pc)
 {
-        int cpu = get_cpu();
-        load_LDT_nolock(pc, cpu);
-        put_cpu();
+        preempt_disable();
+        load_LDT_nolock(pc);
+        preempt_enable();
 }
 
 static inline unsigned long get_desc_base(unsigned long *desc)
diff --git a/include/asm-i386/mmu_context.h b/include/asm-i386/mmu_context.h
index 62b7bf184094..1b1495372c4d 100644
--- a/include/asm-i386/mmu_context.h
+++ b/include/asm-i386/mmu_context.h
@@ -44,7 +44,7 @@ static inline void switch_mm(struct mm_struct *prev,
                  * load the LDT, if the LDT is different:
                  */
                 if (unlikely(prev->context.ldt != next->context.ldt))
-                        load_LDT_nolock(&next->context, cpu);
+                        load_LDT_nolock(&next->context);
         }
 #ifdef CONFIG_SMP
         else {
@@ -56,7 +56,7 @@ static inline void switch_mm(struct mm_struct *prev,
                          * tlb flush IPI delivery. We must reload %cr3.
                          */
                         load_cr3(next->pgd);
-                        load_LDT_nolock(&next->context, cpu);
+                        load_LDT_nolock(&next->context);
                 }
         }
 #endif