--- /dev/null
+/* Written 2000 by Andi Kleen */
+#ifndef _ARCH_DESC_H
+#define _ARCH_DESC_H
+
+#include <arch/ldt.h>
+
+#ifndef __ASSEMBLY__
+
+#include <lwk/string.h>
+#include <lwk/smp.h>
+
+#include <arch/segment.h>
+#include <arch/mmu.h>
+
+// 8 byte segment descriptor
+struct desc_struct {
+ u16 limit0;
+ u16 base0;
+ unsigned base1 : 8, type : 4, s : 1, dpl : 2, p : 1;
+ unsigned limit : 4, avl : 1, l : 1, d : 1, g : 1, base2 : 8;
+} __attribute__((packed));
+
+struct n_desc_struct {
+ unsigned int a,b;
+};
+
+extern struct desc_struct cpu_gdt_table[GDT_ENTRIES];
+
+enum {
+ GATE_INTERRUPT = 0xE,
+ GATE_TRAP = 0xF,
+ GATE_CALL = 0xC,
+};
+
+/**
+ * Long-Mode Gate Descriptor (16-bytes)
+ */
+struct gate_struct {
+ uint16_t offset_low; /* [15-0] of target code segment offset */
+ uint16_t segment; /* Target code segment selector */
+ unsigned ist : 3; /* Interrupt-Stack-Table index into TSS */
+ unsigned zero0 : 5;
+ unsigned type : 5; /* Gate descriptor type */
+ unsigned dpl : 2; /* Privilege level */
+ unsigned p : 1; /* Present bit... in use? */
+ uint16_t offset_middle; /* [31-24] of target code segment offset */
+ uint32_t offset_high; /* [63-32] of target code segment offset */
+ uint32_t zero1;
+} __attribute__((packed));
+
+#define PTR_LOW(x) ((unsigned long)(x) & 0xFFFF)
+#define PTR_MIDDLE(x) (((unsigned long)(x) >> 16) & 0xFFFF)
+#define PTR_HIGH(x) ((unsigned long)(x) >> 32)
+
+enum {
+ DESC_TSS = 0x9,
+ DESC_LDT = 0x2,
+};
+
+// LDT or TSS descriptor in the GDT. 16 bytes.
+struct ldttss_desc {
+ u16 limit0;
+ u16 base0;
+ unsigned base1 : 8, type : 5, dpl : 2, p : 1;
+ unsigned limit1 : 4, zero0 : 3, g : 1, base2 : 8;
+ u32 base3;
+ u32 zero1;
+} __attribute__((packed));
+
+struct desc_ptr {
+ unsigned short size;
+ unsigned long address;
+} __attribute__((packed)) ;
+
+#define load_TR_desc() asm volatile("ltr %w0"::"r" (GDT_ENTRY_TSS*8))
+#define load_LDT_desc() asm volatile("lldt %w0"::"r" (GDT_ENTRY_LDT*8))
+#define clear_LDT() asm volatile("lldt %w0"::"r" (0))
+
+/*
+ * This is the ldt that every process will get unless we need
+ * something other than this.
+ */
+extern struct desc_struct default_ldt[];
+extern struct gate_struct idt_table[];
+extern struct desc_ptr cpu_gdt_descr[];
+
+/* the cpu gdt accessor */
+#define cpu_gdt(_cpu) ((struct desc_struct *)cpu_gdt_descr[_cpu].address)
+
+/**
+ * Installs a Long-Mode gate descriptor.
+ */
+static inline void
+_set_gate(
+ void * adr, /* Address to install gate descriptor at */
+ unsigned type, /* Type of gate */
+ unsigned long func, /* The handler function for the gate */
+ unsigned dpl, /* Privilege level */
+ unsigned ist /* Interupt-Stack-Table index */
+)
+{
+ struct gate_struct s;
+ s.offset_low = PTR_LOW(func);
+ s.segment = __KERNEL_CS;
+ s.ist = ist;
+ s.p = 1;
+ s.dpl = dpl;
+ s.zero0 = 0;
+ s.zero1 = 0;
+ s.type = type;
+ s.offset_middle = PTR_MIDDLE(func);
+ s.offset_high = PTR_HIGH(func);
+ /* does not need to be atomic because it is only done once at setup time */
+ memcpy(adr, &s, 16);
+}
+
+/**
+ * Installs an interrupt gate.
+ * The interrupt will execute on the normal kernel stack.
+ */
+static inline void
+set_intr_gate(int nr, void *func)
+{
+ BUG_ON((unsigned)nr > 0xFF);
+ _set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 0, 0);
+}
+
+/**
+ * Installs an interrupt gate.
+ * The interrupt will execute on the stack specified by the 'ist' argument.
+ */
+static inline void set_intr_gate_ist(int nr, void *func, unsigned ist)
+{
+ BUG_ON((unsigned)nr > 0xFF);
+ _set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 0, ist);
+}
+
+/**
+ * Installs a system interrupt gate.
+ * The privilege level is set to 3, meaning that user-mode can trigger it.
+ */
+static inline void set_system_gate(int nr, void *func)
+{
+ BUG_ON((unsigned)nr > 0xFF);
+ _set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 3, 0);
+}
+
+/**
+ * Installs a system interrupt gate.
+ * The privilege level is set to 3, meaning that user-mode can trigger it.
+ * The interrupt will execute on the stack specified by the 'ist' argument.
+ */
+static inline void set_system_gate_ist(int nr, void *func, unsigned ist)
+{
+ _set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 3, ist);
+}
+
+static inline void set_tssldt_descriptor(void *ptr, unsigned long tss, unsigned type,
+ unsigned size)
+{
+ struct ldttss_desc d;
+ memset(&d,0,sizeof(d));
+ d.limit0 = size & 0xFFFF;
+ d.base0 = PTR_LOW(tss);
+ d.base1 = PTR_MIDDLE(tss) & 0xFF;
+ d.type = type;
+ d.p = 1;
+ d.limit1 = (size >> 16) & 0xF;
+ d.base2 = (PTR_MIDDLE(tss) >> 8) & 0xFF;
+ d.base3 = PTR_HIGH(tss);
+ memcpy(ptr, &d, 16);
+}
+
+static inline void set_tss_desc(unsigned cpu, void *addr)
+{
+ /*
+ * sizeof(unsigned long) coming from an extra "long" at the end
+ * of the iobitmap. See tss_struct definition in processor.h
+ *
+ * -1? seg base+limit should be pointing to the address of the
+ * last valid byte
+ */
+ set_tssldt_descriptor(&cpu_gdt(cpu)[GDT_ENTRY_TSS],
+ (unsigned long)addr, DESC_TSS,
+ IO_BITMAP_OFFSET + IO_BITMAP_BYTES + sizeof(unsigned long) - 1);
+}
+
+static inline void set_ldt_desc(unsigned cpu, void *addr, int size)
+{
+ set_tssldt_descriptor(&cpu_gdt(cpu)[GDT_ENTRY_LDT], (unsigned long)addr,
+ DESC_LDT, size * 8 - 1);
+}
+
+static inline void set_seg_base(unsigned cpu, int entry, void *base)
+{
+ struct desc_struct *d = &cpu_gdt(cpu)[entry];
+ u32 addr = (u32)(u64)base;
+ BUG_ON((u64)base >> 32);
+ d->base0 = addr & 0xffff;
+ d->base1 = (addr >> 16) & 0xff;
+ d->base2 = (addr >> 24) & 0xff;
+}
+
+#define LDT_entry_a(info) \
+ ((((info)->base_addr & 0x0000ffff) << 16) | ((info)->limit & 0x0ffff))
+/* Don't allow setting of the lm bit. It is useless anyways because
+ 64bit system calls require __USER_CS. */
+#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) | \
+ /* ((info)->lm << 21) | */ \
+ 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 && \
+ (info)->lm == 0)
+
+#if TLS_SIZE != 24
+# error update this code.
+#endif
+
+static inline void load_TLS(struct thread_struct *t, unsigned int cpu)
+{
+ u64 *gdt = (u64 *)(cpu_gdt(cpu) + GDT_ENTRY_TLS_MIN);
+ gdt[0] = t->tls_array[0];
+ gdt[1] = t->tls_array[1];
+ gdt[2] = t->tls_array[2];
+}
+
+/*
+ * load one particular LDT into the current CPU
+ */
+static inline void load_LDT_nolock (mm_context_t *pc, int cpu)
+{
+ int count = pc->size;
+
+ if (likely(!count)) {
+ clear_LDT();
+ return;
+ }
+
+ set_ldt_desc(cpu, pc->ldt, count);
+ load_LDT_desc();
+}
+
+static inline void load_LDT(mm_context_t *pc)
+{
+ int cpu = get_cpu();
+ load_LDT_nolock(pc, cpu);
+ put_cpu();
+}
+
+extern struct desc_ptr idt_descr;
+
+#endif /* !__ASSEMBLY__ */
+
+#endif
