Merge tag 'split-asm_system_h-for-linus-20120328' of git://git.kernel.org/pub/scm...
[linux-2.6.git] / arch / x86 / kernel / paravirt.c
1 /*  Paravirtualization interfaces
2     Copyright (C) 2006 Rusty Russell IBM Corporation
3
4     This program is free software; you can redistribute it and/or modify
5     it under the terms of the GNU General Public License as published by
6     the Free Software Foundation; either version 2 of the License, or
7     (at your option) any later version.
8
9     This program is distributed in the hope that it will be useful,
10     but WITHOUT ANY WARRANTY; without even the implied warranty of
11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12     GNU General Public License for more details.
13
14     You should have received a copy of the GNU General Public License
15     along with this program; if not, write to the Free Software
16     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
17
18     2007 - x86_64 support added by Glauber de Oliveira Costa, Red Hat Inc
19 */
20
21 #include <linux/errno.h>
22 #include <linux/module.h>
23 #include <linux/efi.h>
24 #include <linux/bcd.h>
25 #include <linux/highmem.h>
26
27 #include <asm/bug.h>
28 #include <asm/paravirt.h>
29 #include <asm/debugreg.h>
30 #include <asm/desc.h>
31 #include <asm/setup.h>
32 #include <asm/pgtable.h>
33 #include <asm/time.h>
34 #include <asm/pgalloc.h>
35 #include <asm/irq.h>
36 #include <asm/delay.h>
37 #include <asm/fixmap.h>
38 #include <asm/apic.h>
39 #include <asm/tlbflush.h>
40 #include <asm/timer.h>
41 #include <asm/special_insns.h>
42
43 /* nop stub */
44 void _paravirt_nop(void)
45 {
46 }
47
48 /* identity function, which can be inlined */
49 u32 _paravirt_ident_32(u32 x)
50 {
51         return x;
52 }
53
54 u64 _paravirt_ident_64(u64 x)
55 {
56         return x;
57 }
58
59 void __init default_banner(void)
60 {
61         printk(KERN_INFO "Booting paravirtualized kernel on %s\n",
62                pv_info.name);
63 }
64
65 /* Simple instruction patching code. */
66 #define DEF_NATIVE(ops, name, code)                                     \
67         extern const char start_##ops##_##name[], end_##ops##_##name[]; \
68         asm("start_" #ops "_" #name ": " code "; end_" #ops "_" #name ":")
69
70 /* Undefined instruction for dealing with missing ops pointers. */
71 static const unsigned char ud2a[] = { 0x0f, 0x0b };
72
73 unsigned paravirt_patch_nop(void)
74 {
75         return 0;
76 }
77
78 unsigned paravirt_patch_ignore(unsigned len)
79 {
80         return len;
81 }
82
83 struct branch {
84         unsigned char opcode;
85         u32 delta;
86 } __attribute__((packed));
87
88 unsigned paravirt_patch_call(void *insnbuf,
89                              const void *target, u16 tgt_clobbers,
90                              unsigned long addr, u16 site_clobbers,
91                              unsigned len)
92 {
93         struct branch *b = insnbuf;
94         unsigned long delta = (unsigned long)target - (addr+5);
95
96         if (tgt_clobbers & ~site_clobbers)
97                 return len;     /* target would clobber too much for this site */
98         if (len < 5)
99                 return len;     /* call too long for patch site */
100
101         b->opcode = 0xe8; /* call */
102         b->delta = delta;
103         BUILD_BUG_ON(sizeof(*b) != 5);
104
105         return 5;
106 }
107
108 unsigned paravirt_patch_jmp(void *insnbuf, const void *target,
109                             unsigned long addr, unsigned len)
110 {
111         struct branch *b = insnbuf;
112         unsigned long delta = (unsigned long)target - (addr+5);
113
114         if (len < 5)
115                 return len;     /* call too long for patch site */
116
117         b->opcode = 0xe9;       /* jmp */
118         b->delta = delta;
119
120         return 5;
121 }
122
123 /* Neat trick to map patch type back to the call within the
124  * corresponding structure. */
125 static void *get_call_destination(u8 type)
126 {
127         struct paravirt_patch_template tmpl = {
128                 .pv_init_ops = pv_init_ops,
129                 .pv_time_ops = pv_time_ops,
130                 .pv_cpu_ops = pv_cpu_ops,
131                 .pv_irq_ops = pv_irq_ops,
132                 .pv_apic_ops = pv_apic_ops,
133                 .pv_mmu_ops = pv_mmu_ops,
134 #ifdef CONFIG_PARAVIRT_SPINLOCKS
135                 .pv_lock_ops = pv_lock_ops,
136 #endif
137         };
138         return *((void **)&tmpl + type);
139 }
140
141 unsigned paravirt_patch_default(u8 type, u16 clobbers, void *insnbuf,
142                                 unsigned long addr, unsigned len)
143 {
144         void *opfunc = get_call_destination(type);
145         unsigned ret;
146
147         if (opfunc == NULL)
148                 /* If there's no function, patch it with a ud2a (BUG) */
149                 ret = paravirt_patch_insns(insnbuf, len, ud2a, ud2a+sizeof(ud2a));
150         else if (opfunc == _paravirt_nop)
151                 /* If the operation is a nop, then nop the callsite */
152                 ret = paravirt_patch_nop();
153
154         /* identity functions just return their single argument */
155         else if (opfunc == _paravirt_ident_32)
156                 ret = paravirt_patch_ident_32(insnbuf, len);
157         else if (opfunc == _paravirt_ident_64)
158                 ret = paravirt_patch_ident_64(insnbuf, len);
159
160         else if (type == PARAVIRT_PATCH(pv_cpu_ops.iret) ||
161                  type == PARAVIRT_PATCH(pv_cpu_ops.irq_enable_sysexit) ||
162                  type == PARAVIRT_PATCH(pv_cpu_ops.usergs_sysret32) ||
163                  type == PARAVIRT_PATCH(pv_cpu_ops.usergs_sysret64))
164                 /* If operation requires a jmp, then jmp */
165                 ret = paravirt_patch_jmp(insnbuf, opfunc, addr, len);
166         else
167                 /* Otherwise call the function; assume target could
168                    clobber any caller-save reg */
169                 ret = paravirt_patch_call(insnbuf, opfunc, CLBR_ANY,
170                                           addr, clobbers, len);
171
172         return ret;
173 }
174
175 unsigned paravirt_patch_insns(void *insnbuf, unsigned len,
176                               const char *start, const char *end)
177 {
178         unsigned insn_len = end - start;
179
180         if (insn_len > len || start == NULL)
181                 insn_len = len;
182         else
183                 memcpy(insnbuf, start, insn_len);
184
185         return insn_len;
186 }
187
188 static void native_flush_tlb(void)
189 {
190         __native_flush_tlb();
191 }
192
193 /*
194  * Global pages have to be flushed a bit differently. Not a real
195  * performance problem because this does not happen often.
196  */
197 static void native_flush_tlb_global(void)
198 {
199         __native_flush_tlb_global();
200 }
201
202 static void native_flush_tlb_single(unsigned long addr)
203 {
204         __native_flush_tlb_single(addr);
205 }
206
207 struct static_key paravirt_steal_enabled;
208 struct static_key paravirt_steal_rq_enabled;
209
210 static u64 native_steal_clock(int cpu)
211 {
212         return 0;
213 }
214
215 /* These are in entry.S */
216 extern void native_iret(void);
217 extern void native_irq_enable_sysexit(void);
218 extern void native_usergs_sysret32(void);
219 extern void native_usergs_sysret64(void);
220
221 static struct resource reserve_ioports = {
222         .start = 0,
223         .end = IO_SPACE_LIMIT,
224         .name = "paravirt-ioport",
225         .flags = IORESOURCE_IO | IORESOURCE_BUSY,
226 };
227
228 /*
229  * Reserve the whole legacy IO space to prevent any legacy drivers
230  * from wasting time probing for their hardware.  This is a fairly
231  * brute-force approach to disabling all non-virtual drivers.
232  *
233  * Note that this must be called very early to have any effect.
234  */
235 int paravirt_disable_iospace(void)
236 {
237         return request_resource(&ioport_resource, &reserve_ioports);
238 }
239
240 static DEFINE_PER_CPU(enum paravirt_lazy_mode, paravirt_lazy_mode) = PARAVIRT_LAZY_NONE;
241
242 static inline void enter_lazy(enum paravirt_lazy_mode mode)
243 {
244         BUG_ON(percpu_read(paravirt_lazy_mode) != PARAVIRT_LAZY_NONE);
245
246         percpu_write(paravirt_lazy_mode, mode);
247 }
248
249 static void leave_lazy(enum paravirt_lazy_mode mode)
250 {
251         BUG_ON(percpu_read(paravirt_lazy_mode) != mode);
252
253         percpu_write(paravirt_lazy_mode, PARAVIRT_LAZY_NONE);
254 }
255
256 void paravirt_enter_lazy_mmu(void)
257 {
258         enter_lazy(PARAVIRT_LAZY_MMU);
259 }
260
261 void paravirt_leave_lazy_mmu(void)
262 {
263         leave_lazy(PARAVIRT_LAZY_MMU);
264 }
265
266 void paravirt_start_context_switch(struct task_struct *prev)
267 {
268         BUG_ON(preemptible());
269
270         if (percpu_read(paravirt_lazy_mode) == PARAVIRT_LAZY_MMU) {
271                 arch_leave_lazy_mmu_mode();
272                 set_ti_thread_flag(task_thread_info(prev), TIF_LAZY_MMU_UPDATES);
273         }
274         enter_lazy(PARAVIRT_LAZY_CPU);
275 }
276
277 void paravirt_end_context_switch(struct task_struct *next)
278 {
279         BUG_ON(preemptible());
280
281         leave_lazy(PARAVIRT_LAZY_CPU);
282
283         if (test_and_clear_ti_thread_flag(task_thread_info(next), TIF_LAZY_MMU_UPDATES))
284                 arch_enter_lazy_mmu_mode();
285 }
286
287 enum paravirt_lazy_mode paravirt_get_lazy_mode(void)
288 {
289         if (in_interrupt())
290                 return PARAVIRT_LAZY_NONE;
291
292         return percpu_read(paravirt_lazy_mode);
293 }
294
295 void arch_flush_lazy_mmu_mode(void)
296 {
297         preempt_disable();
298
299         if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) {
300                 arch_leave_lazy_mmu_mode();
301                 arch_enter_lazy_mmu_mode();
302         }
303
304         preempt_enable();
305 }
306
307 struct pv_info pv_info = {
308         .name = "bare hardware",
309         .paravirt_enabled = 0,
310         .kernel_rpl = 0,
311         .shared_kernel_pmd = 1, /* Only used when CONFIG_X86_PAE is set */
312
313 #ifdef CONFIG_X86_64
314         .extra_user_64bit_cs = __USER_CS,
315 #endif
316 };
317
318 struct pv_init_ops pv_init_ops = {
319         .patch = native_patch,
320 };
321
322 struct pv_time_ops pv_time_ops = {
323         .sched_clock = native_sched_clock,
324         .steal_clock = native_steal_clock,
325 };
326
327 struct pv_irq_ops pv_irq_ops = {
328         .save_fl = __PV_IS_CALLEE_SAVE(native_save_fl),
329         .restore_fl = __PV_IS_CALLEE_SAVE(native_restore_fl),
330         .irq_disable = __PV_IS_CALLEE_SAVE(native_irq_disable),
331         .irq_enable = __PV_IS_CALLEE_SAVE(native_irq_enable),
332         .safe_halt = native_safe_halt,
333         .halt = native_halt,
334 #ifdef CONFIG_X86_64
335         .adjust_exception_frame = paravirt_nop,
336 #endif
337 };
338
339 struct pv_cpu_ops pv_cpu_ops = {
340         .cpuid = native_cpuid,
341         .get_debugreg = native_get_debugreg,
342         .set_debugreg = native_set_debugreg,
343         .clts = native_clts,
344         .read_cr0 = native_read_cr0,
345         .write_cr0 = native_write_cr0,
346         .read_cr4 = native_read_cr4,
347         .read_cr4_safe = native_read_cr4_safe,
348         .write_cr4 = native_write_cr4,
349 #ifdef CONFIG_X86_64
350         .read_cr8 = native_read_cr8,
351         .write_cr8 = native_write_cr8,
352 #endif
353         .wbinvd = native_wbinvd,
354         .read_msr = native_read_msr_safe,
355         .rdmsr_regs = native_rdmsr_safe_regs,
356         .write_msr = native_write_msr_safe,
357         .wrmsr_regs = native_wrmsr_safe_regs,
358         .read_tsc = native_read_tsc,
359         .read_pmc = native_read_pmc,
360         .read_tscp = native_read_tscp,
361         .load_tr_desc = native_load_tr_desc,
362         .set_ldt = native_set_ldt,
363         .load_gdt = native_load_gdt,
364         .load_idt = native_load_idt,
365         .store_gdt = native_store_gdt,
366         .store_idt = native_store_idt,
367         .store_tr = native_store_tr,
368         .load_tls = native_load_tls,
369 #ifdef CONFIG_X86_64
370         .load_gs_index = native_load_gs_index,
371 #endif
372         .write_ldt_entry = native_write_ldt_entry,
373         .write_gdt_entry = native_write_gdt_entry,
374         .write_idt_entry = native_write_idt_entry,
375
376         .alloc_ldt = paravirt_nop,
377         .free_ldt = paravirt_nop,
378
379         .load_sp0 = native_load_sp0,
380
381 #if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)
382         .irq_enable_sysexit = native_irq_enable_sysexit,
383 #endif
384 #ifdef CONFIG_X86_64
385 #ifdef CONFIG_IA32_EMULATION
386         .usergs_sysret32 = native_usergs_sysret32,
387 #endif
388         .usergs_sysret64 = native_usergs_sysret64,
389 #endif
390         .iret = native_iret,
391         .swapgs = native_swapgs,
392
393         .set_iopl_mask = native_set_iopl_mask,
394         .io_delay = native_io_delay,
395
396         .start_context_switch = paravirt_nop,
397         .end_context_switch = paravirt_nop,
398 };
399
400 struct pv_apic_ops pv_apic_ops = {
401 #ifdef CONFIG_X86_LOCAL_APIC
402         .startup_ipi_hook = paravirt_nop,
403 #endif
404 };
405
406 #if defined(CONFIG_X86_32) && !defined(CONFIG_X86_PAE)
407 /* 32-bit pagetable entries */
408 #define PTE_IDENT       __PV_IS_CALLEE_SAVE(_paravirt_ident_32)
409 #else
410 /* 64-bit pagetable entries */
411 #define PTE_IDENT       __PV_IS_CALLEE_SAVE(_paravirt_ident_64)
412 #endif
413
414 struct pv_mmu_ops pv_mmu_ops = {
415
416         .read_cr2 = native_read_cr2,
417         .write_cr2 = native_write_cr2,
418         .read_cr3 = native_read_cr3,
419         .write_cr3 = native_write_cr3,
420
421         .flush_tlb_user = native_flush_tlb,
422         .flush_tlb_kernel = native_flush_tlb_global,
423         .flush_tlb_single = native_flush_tlb_single,
424         .flush_tlb_others = native_flush_tlb_others,
425
426         .pgd_alloc = __paravirt_pgd_alloc,
427         .pgd_free = paravirt_nop,
428
429         .alloc_pte = paravirt_nop,
430         .alloc_pmd = paravirt_nop,
431         .alloc_pud = paravirt_nop,
432         .release_pte = paravirt_nop,
433         .release_pmd = paravirt_nop,
434         .release_pud = paravirt_nop,
435
436         .set_pte = native_set_pte,
437         .set_pte_at = native_set_pte_at,
438         .set_pmd = native_set_pmd,
439         .set_pmd_at = native_set_pmd_at,
440         .pte_update = paravirt_nop,
441         .pte_update_defer = paravirt_nop,
442         .pmd_update = paravirt_nop,
443         .pmd_update_defer = paravirt_nop,
444
445         .ptep_modify_prot_start = __ptep_modify_prot_start,
446         .ptep_modify_prot_commit = __ptep_modify_prot_commit,
447
448 #if PAGETABLE_LEVELS >= 3
449 #ifdef CONFIG_X86_PAE
450         .set_pte_atomic = native_set_pte_atomic,
451         .pte_clear = native_pte_clear,
452         .pmd_clear = native_pmd_clear,
453 #endif
454         .set_pud = native_set_pud,
455
456         .pmd_val = PTE_IDENT,
457         .make_pmd = PTE_IDENT,
458
459 #if PAGETABLE_LEVELS == 4
460         .pud_val = PTE_IDENT,
461         .make_pud = PTE_IDENT,
462
463         .set_pgd = native_set_pgd,
464 #endif
465 #endif /* PAGETABLE_LEVELS >= 3 */
466
467         .pte_val = PTE_IDENT,
468         .pgd_val = PTE_IDENT,
469
470         .make_pte = PTE_IDENT,
471         .make_pgd = PTE_IDENT,
472
473         .dup_mmap = paravirt_nop,
474         .exit_mmap = paravirt_nop,
475         .activate_mm = paravirt_nop,
476
477         .lazy_mode = {
478                 .enter = paravirt_nop,
479                 .leave = paravirt_nop,
480         },
481
482         .set_fixmap = native_set_fixmap,
483 };
484
485 EXPORT_SYMBOL_GPL(pv_time_ops);
486 EXPORT_SYMBOL    (pv_cpu_ops);
487 EXPORT_SYMBOL    (pv_mmu_ops);
488 EXPORT_SYMBOL_GPL(pv_apic_ops);
489 EXPORT_SYMBOL_GPL(pv_info);
490 EXPORT_SYMBOL    (pv_irq_ops);