Add an acessor function to get a pointer to an LDT descriptor. Add one for
the GDT too, while we are here, and a function to tell the difference.
Turns out on some GCC versions, converting to char * and back gives better
code output than gdt[seg >> 3]. Lets keep that trick in the header file
so the C-code can be clean.
Not used yet, but soon.
Signed-off-by: Zachary Amsden <zach@vmware.com>
Index: linux-2.6.14-zach-work/include/asm-i386/desc.h
==================================================================---
linux-2.6.14-zach-work.orig/include/asm-i386/desc.h 2005-11-04
18:10:53.000000000 -0800
+++ linux-2.6.14-zach-work/include/asm-i386/desc.h 2005-11-05 00:28:03.000000000
-0800
@@ -30,7 +30,24 @@ static inline struct desc_struct *get_cp
{
return ((struct desc_struct *)cpu_gdt_descr[cpu].address);
}
-
+
+static inline int segment_from_ldt(unsigned int segment)
+{
+ return segment & LDT_SEGMENT;
+}
+
+static inline struct desc_struct *get_gdt_desc(int cpu, unsigned int segment)
+{
+ char *gdt = (char *)get_cpu_gdt_table(cpu);
+ return (struct desc_struct *)&gdt[segment & ~7];
+}
+
+static inline struct desc_struct *get_ldt_desc(mm_context_t *ctx, unsigned int
segment)
+{
+ char *ldt = (char *)ctx->ldt;
+ return (struct desc_struct *)&ldt[segment & ~7];
+}
+
#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))
