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 */
_paravirt_nop(void)44 void _paravirt_nop(void)
45 {
46 }
47
48 /* identity function, which can be inlined */
_paravirt_ident_32(u32 x)49 u32 _paravirt_ident_32(u32 x)
50 {
51 return x;
52 }
53
_paravirt_ident_64(u64 x)54 u64 _paravirt_ident_64(u64 x)
55 {
56 return x;
57 }
58
default_banner(void)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
paravirt_patch_nop(void)73 unsigned paravirt_patch_nop(void)
74 {
75 return 0;
76 }
77
paravirt_patch_ignore(unsigned len)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
paravirt_patch_call(void * insnbuf,const void * target,u16 tgt_clobbers,unsigned long addr,u16 site_clobbers,unsigned len)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
paravirt_patch_jmp(void * insnbuf,const void * target,unsigned long addr,unsigned len)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. */
get_call_destination(u8 type)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
paravirt_patch_default(u8 type,u16 clobbers,void * insnbuf,unsigned long addr,unsigned len)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
paravirt_patch_insns(void * insnbuf,unsigned len,const char * start,const char * end)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
native_flush_tlb(void)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 */
native_flush_tlb_global(void)197 static void native_flush_tlb_global(void)
198 {
199 __native_flush_tlb_global();
200 }
201
native_flush_tlb_single(unsigned long addr)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
native_steal_clock(int cpu)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 */
paravirt_disable_iospace(void)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
enter_lazy(enum paravirt_lazy_mode mode)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
leave_lazy(enum paravirt_lazy_mode mode)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
paravirt_enter_lazy_mmu(void)256 void paravirt_enter_lazy_mmu(void)
257 {
258 enter_lazy(PARAVIRT_LAZY_MMU);
259 }
260
paravirt_leave_lazy_mmu(void)261 void paravirt_leave_lazy_mmu(void)
262 {
263 leave_lazy(PARAVIRT_LAZY_MMU);
264 }
265
paravirt_flush_lazy_mmu(void)266 void paravirt_flush_lazy_mmu(void)
267 {
268 preempt_disable();
269
270 if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) {
271 arch_leave_lazy_mmu_mode();
272 arch_enter_lazy_mmu_mode();
273 }
274
275 preempt_enable();
276 }
277
paravirt_start_context_switch(struct task_struct * prev)278 void paravirt_start_context_switch(struct task_struct *prev)
279 {
280 BUG_ON(preemptible());
281
282 if (percpu_read(paravirt_lazy_mode) == PARAVIRT_LAZY_MMU) {
283 arch_leave_lazy_mmu_mode();
284 set_ti_thread_flag(task_thread_info(prev), TIF_LAZY_MMU_UPDATES);
285 }
286 enter_lazy(PARAVIRT_LAZY_CPU);
287 }
288
paravirt_end_context_switch(struct task_struct * next)289 void paravirt_end_context_switch(struct task_struct *next)
290 {
291 BUG_ON(preemptible());
292
293 leave_lazy(PARAVIRT_LAZY_CPU);
294
295 if (test_and_clear_ti_thread_flag(task_thread_info(next), TIF_LAZY_MMU_UPDATES))
296 arch_enter_lazy_mmu_mode();
297 }
298
paravirt_get_lazy_mode(void)299 enum paravirt_lazy_mode paravirt_get_lazy_mode(void)
300 {
301 if (in_interrupt())
302 return PARAVIRT_LAZY_NONE;
303
304 return percpu_read(paravirt_lazy_mode);
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 .flush = paravirt_nop,
481 },
482
483 .set_fixmap = native_set_fixmap,
484 };
485
486 EXPORT_SYMBOL_GPL(pv_time_ops);
487 EXPORT_SYMBOL (pv_cpu_ops);
488 EXPORT_SYMBOL (pv_mmu_ops);
489 EXPORT_SYMBOL_GPL(pv_apic_ops);
490 EXPORT_SYMBOL_GPL(pv_info);
491 EXPORT_SYMBOL (pv_irq_ops);
492