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