x86: use descriptor's functions instead of inline assembly

This patch provides a new set of functions for managing the descriptor
tables that can be used instead of putting the raw assembly in .c files.

Remodeling of store_tr() suggested by Frederik Deweerdt.

[ tglx: arch/x86 adaptation ]

Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 30 insertions, 0 deletions

diff --git a/include/asm-x86/desc_64.h b/include/asm-x86/desc_64.h
index ac991b5ca0fd..7d9c938e69fd 100644
--- a/include/asm-x86/desc_64.h
+++ b/include/asm-x86/desc_64.h
@@ -20,6 +20,16 @@ extern struct desc_struct cpu_gdt_table[GDT_ENTRIES];
 #define load_LDT_desc() asm volatile("lldt %w0"::"r" (GDT_ENTRY_LDT*8))
 #define clear_LDT()  asm volatile("lldt %w0"::"r" (0))
 
+static inline unsigned long __store_tr(void)
+{
+       unsigned long tr;
+
+       asm volatile ("str %w0":"=r" (tr));
+       return tr;
+}
+
+#define store_tr(tr) (tr) = __store_tr()
+
 /*
  * This is the ldt that every process will get unless we need
  * something other than this.
@@ -31,6 +41,16 @@ extern struct desc_ptr cpu_gdt_descr[];
 /* the cpu gdt accessor */
 #define cpu_gdt(_cpu) ((struct desc_struct *)cpu_gdt_descr[_cpu].address)
 
+static inline void load_gdt(const struct desc_ptr *ptr)
+{
+        asm volatile("lgdt %w0"::"m" (*ptr));
+}
+
+static inline void store_gdt(struct desc_ptr *ptr)
+{
+       asm("sgdt %w0":"=m" (*ptr));
+}
+
 static inline void _set_gate(void *adr, unsigned type, unsigned long func, unsigned dpl, unsigned ist)  
 {
         struct gate_struct s;   
@@ -71,6 +91,16 @@ static inline void set_system_gate_ist(int nr, void *func, unsigned ist)
         _set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 3, ist);
 }
 
+static inline void load_idt(const struct desc_ptr *ptr)
+{
+        asm volatile("lidt %w0"::"m" (*ptr));
+}
+
+static inline void store_idt(struct desc_ptr *dtr)
+{
+       asm("sidt %w0":"=m" (*dtr));
+}
+
 static inline void set_tssldt_descriptor(void *ptr, unsigned long tss, unsigned type, 
                                          unsigned size) 
 {