From 49eb099b806bc2049cfe8fbeb9c2f1a309a37878 Mon Sep 17 00:00:00 2001
From: Jacek Galowicz <jacek.galowicz@rwth-aachen.de>
Date: Wed, 13 Jun 2012 09:36:28 +0200
Subject: [PATCH] Reverted the removal of configure_gdt_entry()

Commit 227cc198905c42a52af8076e3f9f3542118f276f
"add alpha version of x64 support"
removed configure_gdt_entry(), but this is used within the
lguest branch.
---
 arch/x86/include/asm/gdt.h | 10 ++++++++++
 arch/x86/kernel/gdt.c      | 28 +++++++++++++++-------------
 2 files changed, 25 insertions(+), 13 deletions(-)

diff --git a/arch/x86/include/asm/gdt.h b/arch/x86/include/asm/gdt.h
index 75f8ffe8..c86a5d4b 100644
--- a/arch/x86/include/asm/gdt.h
+++ b/arch/x86/include/asm/gdt.h
@@ -122,6 +122,16 @@ typedef struct {
  */
 void gdt_install(void);
 
+/** @brief Configures and returns a GDT descriptor with chosen attributes
+ *
+ * Just feed this function with address, limit and the flags
+ * you have seen in idt.h
+ *
+ * @return a preconfigured gdt descriptor
+ */
+void configure_gdt_entry(gdt_entry_t *dest_entry, unsigned long base, unsigned long limit,
+		unsigned char access, unsigned char gran);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/arch/x86/kernel/gdt.c b/arch/x86/kernel/gdt.c
index c625c8c1..c5a1e673 100644
--- a/arch/x86/kernel/gdt.c
+++ b/arch/x86/kernel/gdt.c
@@ -188,26 +188,28 @@ int create_default_frame(task_t* task, entry_point_t ep, void* arg)
 	return 0;
 }
 
-/** @brief Configures GDT descriptor with chosen attributes
- *
- * Just feed this function with address, limit and the flags 
- * you have seen in gdt.h
- */
+/* Setup a descriptor in the Global Descriptor Table */
 static void gdt_set_gate(int num, unsigned long base, unsigned long limit,
-			unsigned char access, unsigned char gran)
+			  unsigned char access, unsigned char gran)
+{
+	configure_gdt_entry(&gdt[num], base, limit, access, gran);
+}
+
+void configure_gdt_entry(gdt_entry_t *dest_entry, unsigned long base, unsigned long limit,
+		unsigned char access, unsigned char gran)
 {
 	/* Setup the descriptor base address */
-	gdt[num].base_low = (base & 0xFFFF);
-	gdt[num].base_middle = (base >> 16) & 0xFF;
-	gdt[num].base_high = (base >> 24) & 0xFF;
+	dest_entry->base_low = (base & 0xFFFF);
+	dest_entry->base_middle = (base >> 16) & 0xFF;
+	dest_entry->base_high = (base >> 24) & 0xFF;
 
 	/* Setup the descriptor limits */
-	gdt[num].limit_low = (limit & 0xFFFF);
-	gdt[num].granularity = ((limit >> 16) & 0x0F);
+	dest_entry->limit_low = (limit & 0xFFFF);
+	dest_entry->granularity = ((limit >> 16) & 0x0F);
 
 	/* Finally, set up the granularity and access flags */
-	gdt[num].granularity |= (gran & 0xF0);
-	gdt[num].access = access;
+	dest_entry->granularity |= (gran & 0xF0);
+	dest_entry->access = access;
 }
 
 /*