1 files changed, 144 insertions, 0 deletions

diff --git a/include/asm-i386/desc.h b/include/asm-i386/desc.h
new file mode 100644
index 000000000000..11e67811a990
--- /dev/null
+++ b/include/asm-i386/desc.h
@@ -0,0 +1,144 @@
+#ifndef __ARCH_DESC_H
+#define __ARCH_DESC_H
+
+#include <asm/ldt.h>
+#include <asm/segment.h>
+
+#define CPU_16BIT_STACK_SIZE 1024
+
+#ifndef __ASSEMBLY__
+
+#include <linux/preempt.h>
+#include <linux/smp.h>
+#include <linux/percpu.h>
+
+#include <asm/mmu.h>
+
+extern struct desc_struct cpu_gdt_table[GDT_ENTRIES];
+DECLARE_PER_CPU(struct desc_struct, cpu_gdt_table[GDT_ENTRIES]);
+
+DECLARE_PER_CPU(unsigned char, cpu_16bit_stack[CPU_16BIT_STACK_SIZE]);
+
+struct Xgt_desc_struct {
+	unsigned short size;
+	unsigned long address __attribute__((packed));
+	unsigned short pad;
+} __attribute__ ((packed));
+
+extern struct Xgt_desc_struct idt_descr, cpu_gdt_descr[NR_CPUS];
+
+#define load_TR_desc() __asm__ __volatile__("ltr %%ax"::"a" (GDT_ENTRY_TSS*8))
+#define load_LDT_desc() __asm__ __volatile__("lldt %%ax"::"a" (GDT_ENTRY_LDT*8))
+
+/*
+ * This is the ldt that every process will get unless we need
+ * something other than this.
+ */
+extern struct desc_struct default_ldt[];
+extern void set_intr_gate(unsigned int irq, void * addr);
+
+#define _set_tssldt_desc(n,addr,limit,type) \
+__asm__ __volatile__ ("movw %w3,0(%2)\n\t" \
+	"movw %%ax,2(%2)\n\t" \
+	"rorl $16,%%eax\n\t" \
+	"movb %%al,4(%2)\n\t" \
+	"movb %4,5(%2)\n\t" \
+	"movb $0,6(%2)\n\t" \
+	"movb %%ah,7(%2)\n\t" \
+	"rorl $16,%%eax" \
+	: "=m"(*(n)) : "a" (addr), "r"(n), "ir"(limit), "i"(type))
+
+static inline void __set_tss_desc(unsigned int cpu, unsigned int entry, void *addr)
+{
+	_set_tssldt_desc(&per_cpu(cpu_gdt_table, cpu)[entry], (int)addr,
+		offsetof(struct tss_struct, __cacheline_filler) - 1, 0x89);
+}
+
+#define set_tss_desc(cpu,addr) __set_tss_desc(cpu, GDT_ENTRY_TSS, addr)
+
+static inline void set_ldt_desc(unsigned int cpu, void *addr, unsigned int size)
+{
+	_set_tssldt_desc(&per_cpu(cpu_gdt_table, cpu)[GDT_ENTRY_LDT], (int)addr, ((size << 3)-1), 0x82);
+}
+
+#define LDT_entry_a(info) \
+	((((info)->base_addr & 0x0000ffff) << 16) | ((info)->limit & 0x0ffff))
+
+#define LDT_entry_b(info) \
+	(((info)->base_addr & 0xff000000) | \
+	(((info)->base_addr & 0x00ff0000) >> 16) | \
+	((info)->limit & 0xf0000) | \
+	(((info)->read_exec_only ^ 1) << 9) | \
+	((info)->contents << 10) | \
+	(((info)->seg_not_present ^ 1) << 15) | \
+	((info)->seg_32bit << 22) | \
+	((info)->limit_in_pages << 23) | \
+	((info)->useable << 20) | \
+	0x7000)
+
+#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	)
+
+#if TLS_SIZE != 24
+# error update this code.
+#endif
+
+static inline void load_TLS(struct thread_struct *t, unsigned int cpu)
+{
+#define C(i) per_cpu(cpu_gdt_table, cpu)[GDT_ENTRY_TLS_MIN + i] = t->tls_array[i]
+	C(0); C(1); C(2);
+#undef C
+}
+
+static inline void clear_LDT(void)
+{
+	int cpu = get_cpu();
+
+	set_ldt_desc(cpu, &default_ldt[0], 5);
+	load_LDT_desc();
+	put_cpu();
+}
+
+/*
+ * load one particular LDT into the current CPU
+ */
+static inline void load_LDT_nolock(mm_context_t *pc, int cpu)
+{
+	void *segments = pc->ldt;
+	int count = pc->size;
+
+	if (likely(!count)) {
+		segments = &default_ldt[0];
+		count = 5;
+	}
+		
+	set_ldt_desc(cpu, segments, count);
+	load_LDT_desc();
+}
+
+static inline void load_LDT(mm_context_t *pc)
+{
+	int cpu = get_cpu();
+	load_LDT_nolock(pc, cpu);
+	put_cpu();
+}
+
+static inline unsigned long get_desc_base(unsigned long *desc)
+{
+	unsigned long base;
+	base = ((desc[0] >> 16)  & 0x0000ffff) |
+		((desc[1] << 16) & 0x00ff0000) |
+		(desc[1] & 0xff000000);
+	return base;
+}
+
+#endif /* !__ASSEMBLY__ */
+
+#endif