x86: unify non-paravirt parts of desc.h

This patch unifies the non-paravirt part of desc_{32,64}.h into
desc.h. Most of it, is simply common code, that is moved to
the shared header. The only exception is the set_ldt_desc in desc_64.h,
which is changed - included its name - to accomodate for the way
the ldt is set up in i386.

Also, constant definitions used in desc_32.h are moved to desc_defs.h

Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 64 insertions, 1 deletions

diff --git a/include/asm-x86/desc.h b/include/asm-x86/desc.h
index 47086d2d9298..99c4adc851e2 100644
--- a/include/asm-x86/desc.h
+++ b/include/asm-x86/desc.h
@@ -4,6 +4,7 @@
 #ifndef __ASSEMBLY__
 #include <asm/desc_defs.h>
 #include <asm/ldt.h>
+#include <asm/mmu.h>
 
 static inline void fill_ldt(struct desc_struct *desc, struct user_desc *info)
 {
@@ -23,7 +24,8 @@ static inline void fill_ldt(struct desc_struct *desc, struct user_desc *info)
         desc->base2 = (info->base_addr & 0xff000000) >> 24;
 }
 
-#endif
+extern struct desc_ptr idt_descr;
+extern gate_desc idt_table[];
 
 #ifdef CONFIG_X86_32
 # include "desc_32.h"
@@ -31,4 +33,65 @@ static inline void fill_ldt(struct desc_struct *desc, struct user_desc *info)
 # include "desc_64.h"
 #endif
 
+#define _LDT_empty(info) (\
+        (info)->base_addr       == 0    && \
+        (info)->limit           == 0    && \
+        (info)->contents        == 0    && \
+        (info)->read_exec_only  == 1    && \
+        (info)->seg_32bit       == 0    && \
+        (info)->limit_in_pages  == 0    && \
+        (info)->seg_not_present == 1    && \
+        (info)->useable         == 0)
+
+#ifdef CONFIG_X86_64
+#define LDT_empty(info) (_LDT_empty(info) && ((info)->lm == 0))
+#else
+#define LDT_empty(info) (_LDT_empty(info))
+#endif
+
+static inline void clear_LDT(void)
+{
+        set_ldt(NULL, 0);
+}
+
+/*
+ * load one particular LDT into the current CPU
+ */
+static inline void load_LDT_nolock(mm_context_t *pc)
+{
+        set_ldt(pc->ldt, pc->size);
+}
+
+static inline void load_LDT(mm_context_t *pc)
+{
+        preempt_disable();
+        load_LDT_nolock(pc);
+        preempt_enable();
+}
+
+#else
+/*
+ * 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