1 /* Written 2000 by Andi Kleen */
5 #include <linux/threads.h>
10 #include <linux/string.h>
11 #include <linux/smp.h>
13 #include <asm/segment.h>
16 // 8 byte segment descriptor
20 unsigned base1 : 8, type : 4, s : 1, dpl : 2, p : 1;
21 unsigned limit : 4, avl : 1, l : 1, d : 1, g : 1, base2 : 8;
22 } __attribute__((packed));
24 struct n_desc_struct {
28 extern struct desc_struct cpu_gdt_table[NR_CPUS][GDT_ENTRIES];
40 unsigned ist : 3, zero0 : 5, type : 5, dpl : 2, p : 1;
44 } __attribute__((packed));
46 #define PTR_LOW(x) ((unsigned long)(x) & 0xFFFF)
47 #define PTR_MIDDLE(x) (((unsigned long)(x) >> 16) & 0xFFFF)
48 #define PTR_HIGH(x) ((unsigned long)(x) >> 32)
55 // LDT or TSS descriptor in the GDT. 16 bytes.
59 unsigned base1 : 8, type : 5, dpl : 2, p : 1;
60 unsigned limit1 : 4, zero0 : 3, g : 1, base2 : 8;
63 } __attribute__((packed));
67 unsigned long address;
68 } __attribute__((packed)) ;
70 #define load_TR_desc() asm volatile("ltr %w0"::"r" (GDT_ENTRY_TSS*8))
71 #define load_LDT_desc() asm volatile("lldt %w0"::"r" (GDT_ENTRY_LDT*8))
72 #define clear_LDT() asm volatile("lldt %w0"::"r" (0))
75 * This is the ldt that every process will get unless we need
76 * something other than this.
78 extern struct desc_struct default_ldt[];
79 extern struct gate_struct idt_table[];
80 extern struct desc_ptr cpu_gdt_descr[];
82 static inline void _set_gate(void *adr, unsigned type, unsigned long func, unsigned dpl, unsigned ist)
85 s.offset_low = PTR_LOW(func);
86 s.segment = __KERNEL_CS;
93 s.offset_middle = PTR_MIDDLE(func);
94 s.offset_high = PTR_HIGH(func);
95 /* does not need to be atomic because it is only done once at setup time */
99 static inline void set_intr_gate(int nr, void *func)
101 _set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 0, 0);
104 static inline void set_intr_gate_ist(int nr, void *func, unsigned ist)
106 _set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 0, ist);
109 static inline void set_system_gate(int nr, void *func)
111 _set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 3, 0);
114 static inline void set_tssldt_descriptor(void *ptr, unsigned long tss, unsigned type,
117 struct ldttss_desc d;
118 memset(&d,0,sizeof(d));
119 d.limit0 = size & 0xFFFF;
120 d.base0 = PTR_LOW(tss);
121 d.base1 = PTR_MIDDLE(tss) & 0xFF;
124 d.limit1 = (size >> 16) & 0xF;
125 d.base2 = (PTR_MIDDLE(tss) >> 8) & 0xFF;
126 d.base3 = PTR_HIGH(tss);
130 static inline void set_tss_desc(unsigned cpu, void *addr)
132 set_tssldt_descriptor(&cpu_gdt_table[cpu][GDT_ENTRY_TSS], (unsigned long)addr,
134 sizeof(struct tss_struct) - 1);
137 static inline void set_ldt_desc(unsigned cpu, void *addr, int size)
139 set_tssldt_descriptor(&cpu_gdt_table[cpu][GDT_ENTRY_LDT], (unsigned long)addr,
140 DESC_LDT, size * 8 - 1);
143 static inline void set_seg_base(unsigned cpu, int entry, void *base)
145 struct desc_struct *d = &cpu_gdt_table[cpu][entry];
146 u32 addr = (u32)(u64)base;
147 BUG_ON((u64)base >> 32);
148 d->base0 = addr & 0xffff;
149 d->base1 = (addr >> 16) & 0xff;
150 d->base2 = (addr >> 24) & 0xff;
153 #define LDT_entry_a(info) \
154 ((((info)->base_addr & 0x0000ffff) << 16) | ((info)->limit & 0x0ffff))
155 /* Don't allow setting of the lm bit. It is useless anyways because
156 64bit system calls require __USER_CS. */
157 #define LDT_entry_b(info) \
158 (((info)->base_addr & 0xff000000) | \
159 (((info)->base_addr & 0x00ff0000) >> 16) | \
160 ((info)->limit & 0xf0000) | \
161 (((info)->read_exec_only ^ 1) << 9) | \
162 ((info)->contents << 10) | \
163 (((info)->seg_not_present ^ 1) << 15) | \
164 ((info)->seg_32bit << 22) | \
165 ((info)->limit_in_pages << 23) | \
166 ((info)->useable << 20) | \
167 /* ((info)->lm << 21) | */ \
170 #define LDT_empty(info) (\
171 (info)->base_addr == 0 && \
172 (info)->limit == 0 && \
173 (info)->contents == 0 && \
174 (info)->read_exec_only == 1 && \
175 (info)->seg_32bit == 0 && \
176 (info)->limit_in_pages == 0 && \
177 (info)->seg_not_present == 1 && \
178 (info)->useable == 0 && \
182 # error update this code.
185 static inline void load_TLS(struct thread_struct *t, unsigned int cpu)
187 u64 *gdt = (u64 *)(cpu_gdt_table[cpu] + GDT_ENTRY_TLS_MIN);
188 gdt[0] = t->tls_array[0];
189 gdt[1] = t->tls_array[1];
190 gdt[2] = t->tls_array[2];
194 * load one particular LDT into the current CPU
196 static inline void load_LDT_nolock (mm_context_t *pc, int cpu)
198 int count = pc->size;
200 if (likely(!count)) {
205 set_ldt_desc(cpu, pc->ldt, count);
209 static inline void load_LDT(mm_context_t *pc)
212 load_LDT_nolock(pc, cpu);
216 extern struct desc_ptr idt_descr;
218 #endif /* !__ASSEMBLY__ */