1 files changed, 55 insertions, 40 deletions

diff --git a/include/asm-i386/desc.h b/include/asm-i386/desc.h
index 5874ef119ffd..f398cc456448 100644
--- a/include/asm-i386/desc.h
+++ b/include/asm-i386/desc.h
@@ -4,8 +4,6 @@
 #include <asm/ldt.h>
 #include <asm/segment.h>
 
-#define CPU_16BIT_STACK_SIZE 1024
-
 #ifndef __ASSEMBLY__
 
 #include <linux/preempt.h>
@@ -16,8 +14,6 @@
 
 extern struct desc_struct cpu_gdt_table[GDT_ENTRIES];
 
-DECLARE_PER_CPU(unsigned char, cpu_16bit_stack[CPU_16BIT_STACK_SIZE]);
-
 struct Xgt_desc_struct {
         unsigned short size;
         unsigned long address __attribute__((packed));
@@ -33,11 +29,6 @@ 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);
 
@@ -64,8 +55,10 @@ static inline void pack_gate(__u32 *a, __u32 *b,
 #define DESCTYPE_DPL3   0x60    /* DPL-3 */
 #define DESCTYPE_S      0x10    /* !system */
 
+#ifdef CONFIG_PARAVIRT
+#include <asm/paravirt.h>
+#else
 #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))
@@ -88,6 +81,10 @@ static inline void load_TLS(struct thread_struct *t, unsigned int cpu)
 #undef C
 }
 
+#define write_ldt_entry(dt, entry, a, b) write_dt_entry(dt, entry, a, b)
+#define write_gdt_entry(dt, entry, a, b) write_dt_entry(dt, entry, a, b)
+#define write_idt_entry(dt, entry, a, b) write_dt_entry(dt, entry, a, b)
+
 static inline void write_dt_entry(void *dt, int entry, __u32 entry_a, __u32 entry_b)
 {
         __u32 *lp = (__u32 *)((char *)dt + entry*8);
@@ -95,9 +92,25 @@ static inline void write_dt_entry(void *dt, int entry, __u32 entry_a, __u32 entr
         *(lp+1) = entry_b;
 }
 
-#define write_ldt_entry(dt, entry, a, b) write_dt_entry(dt, entry, a, b)
-#define write_gdt_entry(dt, entry, a, b) write_dt_entry(dt, entry, a, b)
-#define write_idt_entry(dt, entry, a, b) write_dt_entry(dt, entry, a, b)
+#define set_ldt native_set_ldt
+#endif /* CONFIG_PARAVIRT */
+
+static inline fastcall void native_set_ldt(const void *addr,
+                                           unsigned int entries)
+{
+        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));
+        }
+}
 
 static inline void _set_gate(int gate, unsigned int type, void *addr, unsigned short seg)
 {
@@ -115,14 +128,6 @@ 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)
-{
-        __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);
-}
 
 #define set_tss_desc(cpu,addr) __set_tss_desc(cpu, GDT_ENTRY_TSS, addr)
 
@@ -153,35 +158,22 @@ 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)
@@ -193,6 +185,29 @@ static inline unsigned long get_desc_base(unsigned long *desc)
         return base;
 }
 
+#else /* __ASSEMBLY__ */
+
+/*
+ * GET_DESC_BASE reads the descriptor base of the specified segment.
+ *
+ * Args:
+ *    idx - descriptor index
+ *    gdt - GDT pointer
+ *    base - 32bit register to which the base will be written
+ *    lo_w - lo word of the "base" register
+ *    lo_b - lo byte of the "base" register
+ *    hi_b - hi byte of the low word of the "base" register
+ *
+ * Example:
+ *    GET_DESC_BASE(GDT_ENTRY_ESPFIX_SS, %ebx, %eax, %ax, %al, %ah)
+ *    Will read the base address of GDT_ENTRY_ESPFIX_SS and put it into %eax.
+ */
+#define GET_DESC_BASE(idx, gdt, base, lo_w, lo_b, hi_b) \
+        movb idx*8+4(gdt), lo_b; \
+        movb idx*8+7(gdt), hi_b; \
+        shll $16, base; \
+        movw idx*8+2(gdt), lo_w;
+
 #endif /* !__ASSEMBLY__ */
 
 #endif