patch-2.1.121 linux/arch/i386/kernel/desc.h

• Lines: 62
• Date: Wed Sep 9 08:56:58 1998
• Orig file: v2.1.120/linux/arch/i386/kernel/desc.h
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.120/linux/arch/i386/kernel/desc.h linux/arch/i386/kernel/desc.h
@@ -0,0 +1,61 @@
+#ifndef __ARCH_DESC_H
+#define __ARCH_DESC_H
+
+struct desc_struct {
+	unsigned long a,b;
+};
+
+extern struct desc_struct gdt_table[];
+extern struct desc_struct *idt, *gdt;
+
+struct Xgt_desc_struct {
+	unsigned short size;
+	unsigned long address __attribute__((packed));
+};
+
+#define idt_descr (*(struct Xgt_desc_struct *)((char *)&idt - 2))
+#define gdt_descr (*(struct Xgt_desc_struct *)((char *)&gdt - 2))
+
+/*
+ * Entry into gdt where to find first TSS. GDT layout:
+ *   0 - null
+ *   1 - not used
+ *   2 - kernel code segment
+ *   3 - kernel data segment
+ *   4 - user code segment
+ *   5 - user data segment
+ *   6 - not used
+ *   7 - not used
+ *   8 - APM BIOS support
+ *   9 - APM BIOS support
+ *  10 - APM BIOS support
+ *  11 - APM BIOS support
+ *  12 - TSS #0
+ *  13 - LDT #0
+ *  14 - TSS #1
+ *  15 - LDT #1
+ */
+#define FIRST_TSS_ENTRY 12
+#define FIRST_LDT_ENTRY (FIRST_TSS_ENTRY+1)
+#define _TSS(n) ((((unsigned long) n)<<4)+(FIRST_TSS_ENTRY<<3))
+#define _LDT(n) ((((unsigned long) n)<<4)+(FIRST_LDT_ENTRY<<3))
+#define load_TR(n) __asm__ __volatile__("ltr %%ax": /* no output */ :"a" (_TSS(n)))
+#define load_ldt(n) __asm__ __volatile__("lldt %%ax": /* no output */ :"a" (_LDT(n)))
+#define store_TR(n) \
+__asm__("str %%ax\n\t" \
+	"subl %2,%%eax\n\t" \
+	"shrl $4,%%eax" \
+	:"=a" (n) \
+	:"0" (0),"i" (FIRST_TSS_ENTRY<<3))
+
+extern void set_intr_gate(unsigned int irq, void * addr);
+extern void set_ldt_desc(unsigned int n, void *addr, unsigned int size);
+extern void set_tss_desc(unsigned int n, void *addr);
+
+/*
+ * This is the ldt that every process will get unless we need
+ * something other than this.
+ */
+extern struct desc_struct default_ldt;
+
+#endif