Merge tag 'bug-for-3.4' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux
[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
42 /* nop stub */
43 void _paravirt_nop(void)
44 {
45 }
46
47 /* identity function, which can be inlined */
48 u32 _paravirt_ident_32(u32 x)
49 {
50         return x;
51 }
52
53 u64 _paravirt_ident_64(u64 x)
54 {
55         return x;
56 }
57
58 void __init default_banner(void)
59 {
60         printk(KERN_INFO "Booting paravirtualized kernel on %s\n",
61                pv_info.name);
62 }
63
64 /* Simple instruction patching code. */
65 #define DEF_NATIVE(ops, name, code)                                     \
66         extern const char start_##ops##_##name[], end_##ops##_##name[]; \
67         asm("start_" #ops "_" #name ": " code "; end_" #ops "_" #name ":")
68
69 /* Undefined instruction for dealing with missing ops pointers. */
70 static const unsigned char ud2a[] = { 0x0f, 0x0b };
71
72 unsigned paravirt_patch_nop(void)
73 {
74         return 0;
75 }
76
77 unsigned paravirt_patch_ignore(unsigned len)
78 {
79         return len;
80 }
81
82 struct branch {
83         unsigned char opcode;
84         u32 delta;
85 } __attribute__((packed));
86
87 unsigned paravirt_patch_call(void *insnbuf,
88                              const void *target, u16 tgt_clobbers,
89                              unsigned long addr, u16 site_clobbers,
90                              unsigned len)
91 {
92         struct branch *b = insnbuf;
93         unsigned long delta = (unsigned long)target - (addr+5);
94
95         if (tgt_clobbers & ~site_clobbers)
96                 return len;     /* target would clobber too much for this site */
97         if (len < 5)
98                 return len;     /* call too long for patch site */
99
100         b->opcode = 0xe8; /* call */
101         b->delta = delta;
102         BUILD_BUG_ON(sizeof(*b) != 5);
103
104         return 5;
105 }
106
107 unsigned paravirt_patch_jmp(void *insnbuf, const void *target,
108                             unsigned long addr, unsigned len)
109 {
110         struct branch *b = insnbuf;
111         unsigned long delta = (unsigned long)target - (addr+5);
112
113         if (len < 5)
114                 return len;     /* call too long for patch site */
115
116         b->opcode = 0xe9;       /* jmp */
117         b->delta = delta;
118
119         return 5;
120 }
121
122 /* Neat trick to map patch type back to the call within the
123  * corresponding structure. */
124 static void *get_call_destination(u8 type)
125 {
126         struct paravirt_patch_template tmpl = {
127                 .pv_init_ops = pv_init_ops,
128                 .pv_time_ops = pv_time_ops,
129                 .pv_cpu_ops = pv_cpu_ops,
130                 .pv_irq_ops = pv_irq_ops,
131                 .pv_apic_ops = pv_apic_ops,
132                 .pv_mmu_ops = pv_mmu_ops,
133 #ifdef CONFIG_PARAVIRT_SPINLOCKS
134                 .pv_lock_ops = pv_lock_ops,
135 #endif
136         };
137         return *((void **)&tmpl + type);
138 }
139
140 unsigned paravirt_patch_default(u8 type, u16 clobbers, void *insnbuf,
141                                 unsigned long addr, unsigned len)
142 {
143         void *opfunc = get_call_destination(type);
144         unsigned ret;
145
146         if (opfunc == NULL)
147                 /* If there's no function, patch it with a ud2a (BUG) */
148                 ret = paravirt_patch_insns(insnbuf, len, ud2a, ud2a+sizeof(ud2a));
149         else if (opfunc == _paravirt_nop)
150                 /* If the operation is a nop, then nop the callsite */
151                 ret = paravirt_patch_nop();
152
153         /* identity functions just return their single argument */
154         else if (opfunc == _paravirt_ident_32)
155                 ret = paravirt_patch_ident_32(insnbuf, len);
156         else if (opfunc == _paravirt_ident_64)
157                 ret = paravirt_patch_ident_64(insnbuf, len);
158
159         else if (type == PARAVIRT_PATCH(pv_cpu_ops.iret) ||
160                  type == PARAVIRT_PATCH(pv_cpu_ops.irq_enable_sysexit) ||
161                  type == PARAVIRT_PATCH(pv_cpu_ops.usergs_sysret32) ||
162                  type == PARAVIRT_PATCH(pv_cpu_ops.usergs_sysret64))
163                 /* If operation requires a jmp, then jmp */
164                 ret = paravirt_patch_jmp(insnbuf, opfunc, addr, len);
165         else
166                 /* Otherwise call the function; assume target could
167                    clobber any caller-save reg */
168                 ret = paravirt_patch_call(insnbuf, opfunc, CLBR_ANY,
169                                           addr, clobbers, len);
170
171         return ret;
172 }
173
174 unsigned paravirt_patch_insns(void *insnbuf, unsigned len,
175                               const char *start, const char *end)
176 {
177         unsigned insn_len = end - start;
178
179         if (insn_len > len || start == NULL)
180                 insn_len = len;
181         else
182                 memcpy(insnbuf, start, insn_len);
183
184         return insn_len;
185 }
186
187 static void native_flush_tlb(void)
188 {
189         __native_flush_tlb();
190 }
191
192 /*
193  * Global pages have to be flushed a bit differently. Not a real
194  * performance problem because this does not happen often.
195  */
196 static void native_flush_tlb_global(void)
197 {
198         __native_flush_tlb_global();
199 }
200
201 static void native_flush_tlb_single(unsigned long addr)
202 {
203         __native_flush_tlb_single(addr);
204 }
205
206 struct static_key paravirt_steal_enabled;
207 struct static_key paravirt_steal_rq_enabled;
208
209 static u64 native_steal_clock(int cpu)
210 {
211         return 0;
212 }
213
214 /* These are in entry.S */
215 extern void native_iret(void);
216 extern void native_irq_enable_sysexit(void);
217 extern void native_usergs_sysret32(void);
218 extern void native_usergs_sysret64(void);
219
220 static struct resource reserve_ioports = {
221         .start = 0,
222         .end = IO_SPACE_LIMIT,
223         .name = "paravirt-ioport",
224         .flags = IORESOURCE_IO | IORESOURCE_BUSY,
225 };
226
227 /*
228  * Reserve the whole legacy IO space to prevent any legacy drivers
229  * from wasting time probing for their hardware.  This is a fairly
230  * brute-force approach to disabling all non-virtual drivers.
231  *
232  * Note that this must be called very early to have any effect.
233  */
234 int paravirt_disable_iospace(void)
235 {
236         return request_resource(&ioport_resource, &reserve_ioports);
237 }
238
239 static DEFINE_PER_CPU(enum paravirt_lazy_mode, paravirt_lazy_mode) = PARAVIRT_LAZY_NONE;
240
241 static inline void enter_lazy(enum paravirt_lazy_mode mode)
242 {
243         BUG_ON(percpu_read(paravirt_lazy_mode) != PARAVIRT_LAZY_NONE);
244
245         percpu_write(paravirt_lazy_mode, mode);
246 }
247
248 static void leave_lazy(enum paravirt_lazy_mode mode)
249 {
250         BUG_ON(percpu_read(paravirt_lazy_mode) != mode);
251
252         percpu_write(paravirt_lazy_mode, PARAVIRT_LAZY_NONE);
253 }
254
255 void paravirt_enter_lazy_mmu(void)
256 {
257         enter_lazy(PARAVIRT_LAZY_MMU);
258 }
259
260 void paravirt_leave_lazy_mmu(void)
261 {
262         leave_lazy(PARAVIRT_LAZY_MMU);
263 }
264
265 void paravirt_start_context_switch(struct task_struct *prev)
266 {
267         BUG_ON(preemptible());
268
269         if (percpu_read(paravirt_lazy_mode) == PARAVIRT_LAZY_MMU) {
270                 arch_leave_lazy_mmu_mode();
271                 set_ti_thread_flag(task_thread_info(prev), TIF_LAZY_MMU_UPDATES);
272         }
273         enter_lazy(PARAVIRT_LAZY_CPU);
274 }
275
276 void paravirt_end_context_switch(struct task_struct *next)
277 {
278         BUG_ON(preemptible());
279
280         leave_lazy(PARAVIRT_LAZY_CPU);
281
282         if (test_and_clear_ti_thread_flag(task_thread_info(next), TIF_LAZY_MMU_UPDATES))
283                 arch_enter_lazy_mmu_mode();
284 }
285
286 enum paravirt_lazy_mode paravirt_get_lazy_mode(void)
287 {
288         if (in_interrupt())
289                 return PARAVIRT_LAZY_NONE;
290
291         return percpu_read(paravirt_lazy_mode);
292 }
293
294 void arch_flush_lazy_mmu_mode(void)
295 {
296         preempt_disable();
297
298         if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) {
299                 arch_leave_lazy_mmu_mode();
300                 arch_enter_lazy_mmu_mode();
301         }
302
303         preempt_enable();
304 }
305
306 struct pv_info pv_info = {
307         .name = "bare hardware",
308         .paravirt_enabled = 0,
309         .kernel_rpl = 0,
310         .shared_kernel_pmd = 1, /* Only used when CONFIG_X86_PAE is set */
311
312 #ifdef CONFIG_X86_64
313         .extra_user_64bit_cs = __USER_CS,
314 #endif
315 };
316
317 struct pv_init_ops pv_init_ops = {
318         .patch = native_patch,
319 };
320
321 struct pv_time_ops pv_time_ops = {
322         .sched_clock = native_sched_clock,
323         .steal_clock = native_steal_clock,
324 };
325
326 struct pv_irq_ops pv_irq_ops = {
327         .save_fl = __PV_IS_CALLEE_SAVE(native_save_fl),
328         .restore_fl = __PV_IS_CALLEE_SAVE(native_restore_fl),
329         .irq_disable = __PV_IS_CALLEE_SAVE(native_irq_disable),
330         .irq_enable = __PV_IS_CALLEE_SAVE(native_irq_enable),
331         .safe_halt = native_safe_halt,
332         .halt = native_halt,
333 #ifdef CONFIG_X86_64
334         .adjust_exception_frame = paravirt_nop,
335 #endif
336 };
337
338 struct pv_cpu_ops pv_cpu_ops = {
339         .cpuid = native_cpuid,
340         .get_debugreg = native_get_debugreg,
341         .set_debugreg = native_set_debugreg,
342         .clts = native_clts,
343         .read_cr0 = native_read_cr0,
344         .write_cr0 = native_write_cr0,
345         .read_cr4 = native_read_cr4,
346         .read_cr4_safe = native_read_cr4_safe,
347         .write_cr4 = native_write_cr4,
348 #ifdef CONFIG_X86_64
349         .read_cr8 = native_read_cr8,
350         .write_cr8 = native_write_cr8,
351 #endif
352         .wbinvd = native_wbinvd,
353         .read_msr = native_read_msr_safe,
354         .rdmsr_regs = native_rdmsr_safe_regs,
355         .write_msr = native_write_msr_safe,
356         .wrmsr_regs = native_wrmsr_safe_regs,
357         .read_tsc = native_read_tsc,
358         .read_pmc = native_read_pmc,
359         .read_tscp = native_read_tscp,
360         .load_tr_desc = native_load_tr_desc,
361         .set_ldt = native_set_ldt,
362         .load_gdt = native_load_gdt,
363         .load_idt = native_load_idt,
364         .store_gdt = native_store_gdt,
365         .store_idt = native_store_idt,
366         .store_tr = native_store_tr,
367         .load_tls = native_load_tls,
368 #ifdef CONFIG_X86_64
369         .load_gs_index = native_load_gs_index,
370 #endif
371         .write_ldt_entry = native_write_ldt_entry,
372         .write_gdt_entry = native_write_gdt_entry,
373         .write_idt_entry = native_write_idt_entry,
374
375         .alloc_ldt = paravirt_nop,
376         .free_ldt = paravirt_nop,
377
378         .load_sp0 = native_load_sp0,
379
380 #if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)
381         .irq_enable_sysexit = native_irq_enable_sysexit,
382 #endif
383 #ifdef CONFIG_X86_64
384 #ifdef CONFIG_IA32_EMULATION
385         .usergs_sysret32 = native_usergs_sysret32,
386 #endif
387         .usergs_sysret64 = native_usergs_sysret64,
388 #endif
389         .iret = native_iret,
390         .swapgs = native_swapgs,
391
392         .set_iopl_mask = native_set_iopl_mask,
393         .io_delay = native_io_delay,
394
395         .start_context_switch = paravirt_nop,
396         .end_context_switch = paravirt_nop,
397 };
398
399 struct pv_apic_ops pv_apic_ops = {
400 #ifdef CONFIG_X86_LOCAL_APIC
401         .startup_ipi_hook = paravirt_nop,
402 #endif
403 };
404
405 #if defined(CONFIG_X86_32) && !defined(CONFIG_X86_PAE)
406 /* 32-bit pagetable entries */
407 #define PTE_IDENT       __PV_IS_CALLEE_SAVE(_paravirt_ident_32)
408 #else
409 /* 64-bit pagetable entries */
410 #define PTE_IDENT       __PV_IS_CALLEE_SAVE(_paravirt_ident_64)
411 #endif
412
413 struct pv_mmu_ops pv_mmu_ops = {
414
415         .read_cr2 = native_read_cr2,
416         .write_cr2 = native_write_cr2,
417         .read_cr3 = native_read_cr3,
418         .write_cr3 = native_write_cr3,
419
420         .flush_tlb_user = native_flush_tlb,
421         .flush_tlb_kernel = native_flush_tlb_global,
422         .flush_tlb_single = native_flush_tlb_single,
423         .flush_tlb_others = native_flush_tlb_others,
424
425         .pgd_alloc = __paravirt_pgd_alloc,
426         .pgd_free = paravirt_nop,
427
428         .alloc_pte = paravirt_nop,
429         .alloc_pmd = paravirt_nop,
430         .alloc_pud = paravirt_nop,
431         .release_pte = paravirt_nop,
432         .release_pmd = paravirt_nop,
433         .release_pud = paravirt_nop,
434
435         .set_pte = native_set_pte,
436         .set_pte_at = native_set_pte_at,
437         .set_pmd = native_set_pmd,
438         .set_pmd_at = native_set_pmd_at,
439         .pte_update = paravirt_nop,
440         .pte_update_defer = paravirt_nop,
441         .pmd_update = paravirt_nop,
442         .pmd_update_defer = paravirt_nop,
443
444         .ptep_modify_prot_start = __ptep_modify_prot_start,
445         .ptep_modify_prot_commit = __ptep_modify_prot_commit,
446
447 #if PAGETABLE_LEVELS >= 3
448 #ifdef CONFIG_X86_PAE
449         .set_pte_atomic = native_set_pte_atomic,
450         .pte_clear = native_pte_clear,
451         .pmd_clear = native_pmd_clear,
452 #endif
453         .set_pud = native_set_pud,
454
455         .pmd_val = PTE_IDENT,
456         .make_pmd = PTE_IDENT,
457
458 #if PAGETABLE_LEVELS == 4
459         .pud_val = PTE_IDENT,
460         .make_pud = PTE_IDENT,
461
462         .set_pgd = native_set_pgd,
463 #endif
464 #endif /* PAGETABLE_LEVELS >= 3 */
465
466         .pte_val = PTE_IDENT,
467         .pgd_val = PTE_IDENT,
468
469         .make_pte = PTE_IDENT,
470         .make_pgd = PTE_IDENT,
471
472         .dup_mmap = paravirt_nop,
473         .exit_mmap = paravirt_nop,
474         .activate_mm = paravirt_nop,
475
476         .lazy_mode = {
477                 .enter = paravirt_nop,
478                 .leave = paravirt_nop,
479         },
480
481         .set_fixmap = native_set_fixmap,
482 };
483
484 EXPORT_SYMBOL_GPL(pv_time_ops);
485 EXPORT_SYMBOL    (pv_cpu_ops);
486 EXPORT_SYMBOL    (pv_mmu_ops);
487 EXPORT_SYMBOL_GPL(pv_apic_ops);
488 EXPORT_SYMBOL_GPL(pv_info);
489 EXPORT_SYMBOL    (pv_irq_ops);