~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/arch/x86/kernel/paravirt.c

Version: ~ [ linux-5.14-rc1 ] ~ [ linux-5.13.1 ] ~ [ linux-5.12.16 ] ~ [ linux-5.11.22 ] ~ [ linux-5.10.49 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.131 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.197 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.239 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.275 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.275 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.18.140 ] ~ [ linux-3.16.85 ] ~ [ linux-3.14.79 ] ~ [ linux-3.12.74 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  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 #include <linux/kprobes.h>
 27 
 28 #include <asm/bug.h>
 29 #include <asm/paravirt.h>
 30 #include <asm/debugreg.h>
 31 #include <asm/desc.h>
 32 #include <asm/setup.h>
 33 #include <asm/pgtable.h>
 34 #include <asm/time.h>
 35 #include <asm/pgalloc.h>
 36 #include <asm/irq.h>
 37 #include <asm/delay.h>
 38 #include <asm/fixmap.h>
 39 #include <asm/apic.h>
 40 #include <asm/tlbflush.h>
 41 #include <asm/timer.h>
 42 #include <asm/special_insns.h>
 43 
 44 /*
 45  * nop stub, which must not clobber anything *including the stack* to
 46  * avoid confusing the entry prologues.
 47  */
 48 extern void _paravirt_nop(void);
 49 asm (".pushsection .entry.text, \"ax\"\n"
 50      ".global _paravirt_nop\n"
 51      "_paravirt_nop:\n\t"
 52      "ret\n\t"
 53      ".size _paravirt_nop, . - _paravirt_nop\n\t"
 54      ".type _paravirt_nop, @function\n\t"
 55      ".popsection");
 56 
 57 /* identity function, which can be inlined */
 58 u32 notrace _paravirt_ident_32(u32 x)
 59 {
 60         return x;
 61 }
 62 
 63 u64 notrace _paravirt_ident_64(u64 x)
 64 {
 65         return x;
 66 }
 67 
 68 void __init default_banner(void)
 69 {
 70         printk(KERN_INFO "Booting paravirtualized kernel on %s\n",
 71                pv_info.name);
 72 }
 73 
 74 /* Undefined instruction for dealing with missing ops pointers. */
 75 static const unsigned char ud2a[] = { 0x0f, 0x0b };
 76 
 77 unsigned paravirt_patch_nop(void)
 78 {
 79         return 0;
 80 }
 81 
 82 unsigned paravirt_patch_ignore(unsigned len)
 83 {
 84         return len;
 85 }
 86 
 87 struct branch {
 88         unsigned char opcode;
 89         u32 delta;
 90 } __attribute__((packed));
 91 
 92 unsigned paravirt_patch_call(void *insnbuf,
 93                              const void *target, u16 tgt_clobbers,
 94                              unsigned long addr, u16 site_clobbers,
 95                              unsigned len)
 96 {
 97         struct branch *b = insnbuf;
 98         unsigned long delta = (unsigned long)target - (addr+5);
 99 
100         if (tgt_clobbers & ~site_clobbers)
101                 return len;     /* target would clobber too much for this site */
102         if (len < 5)
103                 return len;     /* call too long for patch site */
104 
105         b->opcode = 0xe8; /* call */
106         b->delta = delta;
107         BUILD_BUG_ON(sizeof(*b) != 5);
108 
109         return 5;
110 }
111 
112 unsigned paravirt_patch_jmp(void *insnbuf, const void *target,
113                             unsigned long addr, unsigned len)
114 {
115         struct branch *b = insnbuf;
116         unsigned long delta = (unsigned long)target - (addr+5);
117 
118         if (len < 5)
119                 return len;     /* call too long for patch site */
120 
121         b->opcode = 0xe9;       /* jmp */
122         b->delta = delta;
123 
124         return 5;
125 }
126 
127 /* Neat trick to map patch type back to the call within the
128  * corresponding structure. */
129 static void *get_call_destination(u8 type)
130 {
131         struct paravirt_patch_template tmpl = {
132                 .pv_init_ops = pv_init_ops,
133                 .pv_time_ops = pv_time_ops,
134                 .pv_cpu_ops = pv_cpu_ops,
135                 .pv_irq_ops = pv_irq_ops,
136                 .pv_apic_ops = pv_apic_ops,
137                 .pv_mmu_ops = pv_mmu_ops,
138 #ifdef CONFIG_PARAVIRT_SPINLOCKS
139                 .pv_lock_ops = pv_lock_ops,
140 #endif
141         };
142         return *((void **)&tmpl + type);
143 }
144 
145 unsigned paravirt_patch_default(u8 type, u16 clobbers, void *insnbuf,
146                                 unsigned long addr, unsigned len)
147 {
148         void *opfunc = get_call_destination(type);
149         unsigned ret;
150 
151         if (opfunc == NULL)
152                 /* If there's no function, patch it with a ud2a (BUG) */
153                 ret = paravirt_patch_insns(insnbuf, len, ud2a, ud2a+sizeof(ud2a));
154         else if (opfunc == _paravirt_nop)
155                 /* If the operation is a nop, then nop the callsite */
156                 ret = paravirt_patch_nop();
157 
158         /* identity functions just return their single argument */
159         else if (opfunc == _paravirt_ident_32)
160                 ret = paravirt_patch_ident_32(insnbuf, len);
161         else if (opfunc == _paravirt_ident_64)
162                 ret = paravirt_patch_ident_64(insnbuf, len);
163 
164         else if (type == PARAVIRT_PATCH(pv_cpu_ops.iret) ||
165                  type == PARAVIRT_PATCH(pv_cpu_ops.irq_enable_sysexit) ||
166                  type == PARAVIRT_PATCH(pv_cpu_ops.usergs_sysret32) ||
167                  type == PARAVIRT_PATCH(pv_cpu_ops.usergs_sysret64))
168                 /* If operation requires a jmp, then jmp */
169                 ret = paravirt_patch_jmp(insnbuf, opfunc, addr, len);
170         else
171                 /* Otherwise call the function; assume target could
172                    clobber any caller-save reg */
173                 ret = paravirt_patch_call(insnbuf, opfunc, CLBR_ANY,
174                                           addr, clobbers, len);
175 
176         return ret;
177 }
178 
179 unsigned paravirt_patch_insns(void *insnbuf, unsigned len,
180                               const char *start, const char *end)
181 {
182         unsigned insn_len = end - start;
183 
184         if (insn_len > len || start == NULL)
185                 insn_len = len;
186         else
187                 memcpy(insnbuf, start, insn_len);
188 
189         return insn_len;
190 }
191 
192 static void native_flush_tlb(void)
193 {
194         __native_flush_tlb();
195 }
196 
197 /*
198  * Global pages have to be flushed a bit differently. Not a real
199  * performance problem because this does not happen often.
200  */
201 static void native_flush_tlb_global(void)
202 {
203         __native_flush_tlb_global();
204 }
205 
206 static void native_flush_tlb_single(unsigned long addr)
207 {
208         __native_flush_tlb_single(addr);
209 }
210 
211 struct static_key paravirt_steal_enabled;
212 struct static_key paravirt_steal_rq_enabled;
213 
214 static u64 native_steal_clock(int cpu)
215 {
216         return 0;
217 }
218 
219 /* These are in entry.S */
220 extern void native_iret(void);
221 extern void native_irq_enable_sysexit(void);
222 extern void native_usergs_sysret32(void);
223 extern void native_usergs_sysret64(void);
224 
225 static struct resource reserve_ioports = {
226         .start = 0,
227         .end = IO_SPACE_LIMIT,
228         .name = "paravirt-ioport",
229         .flags = IORESOURCE_IO | IORESOURCE_BUSY,
230 };
231 
232 /*
233  * Reserve the whole legacy IO space to prevent any legacy drivers
234  * from wasting time probing for their hardware.  This is a fairly
235  * brute-force approach to disabling all non-virtual drivers.
236  *
237  * Note that this must be called very early to have any effect.
238  */
239 int paravirt_disable_iospace(void)
240 {
241         return request_resource(&ioport_resource, &reserve_ioports);
242 }
243 
244 static DEFINE_PER_CPU(enum paravirt_lazy_mode, paravirt_lazy_mode) = PARAVIRT_LAZY_NONE;
245 
246 static inline void enter_lazy(enum paravirt_lazy_mode mode)
247 {
248         BUG_ON(this_cpu_read(paravirt_lazy_mode) != PARAVIRT_LAZY_NONE);
249 
250         this_cpu_write(paravirt_lazy_mode, mode);
251 }
252 
253 static void leave_lazy(enum paravirt_lazy_mode mode)
254 {
255         BUG_ON(this_cpu_read(paravirt_lazy_mode) != mode);
256 
257         this_cpu_write(paravirt_lazy_mode, PARAVIRT_LAZY_NONE);
258 }
259 
260 void paravirt_enter_lazy_mmu(void)
261 {
262         enter_lazy(PARAVIRT_LAZY_MMU);
263 }
264 
265 void paravirt_leave_lazy_mmu(void)
266 {
267         leave_lazy(PARAVIRT_LAZY_MMU);
268 }
269 
270 void paravirt_flush_lazy_mmu(void)
271 {
272         preempt_disable();
273 
274         if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) {
275                 arch_leave_lazy_mmu_mode();
276                 arch_enter_lazy_mmu_mode();
277         }
278 
279         preempt_enable();
280 }
281 
282 void paravirt_start_context_switch(struct task_struct *prev)
283 {
284         BUG_ON(preemptible());
285 
286         if (this_cpu_read(paravirt_lazy_mode) == PARAVIRT_LAZY_MMU) {
287                 arch_leave_lazy_mmu_mode();
288                 set_ti_thread_flag(task_thread_info(prev), TIF_LAZY_MMU_UPDATES);
289         }
290         enter_lazy(PARAVIRT_LAZY_CPU);
291 }
292 
293 void paravirt_end_context_switch(struct task_struct *next)
294 {
295         BUG_ON(preemptible());
296 
297         leave_lazy(PARAVIRT_LAZY_CPU);
298 
299         if (test_and_clear_ti_thread_flag(task_thread_info(next), TIF_LAZY_MMU_UPDATES))
300                 arch_enter_lazy_mmu_mode();
301 }
302 
303 enum paravirt_lazy_mode paravirt_get_lazy_mode(void)
304 {
305         if (in_interrupt())
306                 return PARAVIRT_LAZY_NONE;
307 
308         return this_cpu_read(paravirt_lazy_mode);
309 }
310 
311 struct pv_info pv_info = {
312         .name = "bare hardware",
313         .paravirt_enabled = 0,
314         .kernel_rpl = 0,
315         .shared_kernel_pmd = 1, /* Only used when CONFIG_X86_PAE is set */
316 
317 #ifdef CONFIG_X86_64
318         .extra_user_64bit_cs = __USER_CS,
319 #endif
320 };
321 
322 struct pv_init_ops pv_init_ops = {
323         .patch = native_patch,
324 };
325 
326 struct pv_time_ops pv_time_ops = {
327         .sched_clock = native_sched_clock,
328         .steal_clock = native_steal_clock,
329 };
330 
331 __visible struct pv_irq_ops pv_irq_ops = {
332         .save_fl = __PV_IS_CALLEE_SAVE(native_save_fl),
333         .restore_fl = __PV_IS_CALLEE_SAVE(native_restore_fl),
334         .irq_disable = __PV_IS_CALLEE_SAVE(native_irq_disable),
335         .irq_enable = __PV_IS_CALLEE_SAVE(native_irq_enable),
336         .safe_halt = native_safe_halt,
337         .halt = native_halt,
338 #ifdef CONFIG_X86_64
339         .adjust_exception_frame = paravirt_nop,
340 #endif
341 };
342 
343 __visible struct pv_cpu_ops pv_cpu_ops = {
344         .cpuid = native_cpuid,
345         .get_debugreg = native_get_debugreg,
346         .set_debugreg = native_set_debugreg,
347         .clts = native_clts,
348         .read_cr0 = native_read_cr0,
349         .write_cr0 = native_write_cr0,
350         .read_cr4 = native_read_cr4,
351         .read_cr4_safe = native_read_cr4_safe,
352         .write_cr4 = native_write_cr4,
353 #ifdef CONFIG_X86_64
354         .read_cr8 = native_read_cr8,
355         .write_cr8 = native_write_cr8,
356 #endif
357         .wbinvd = native_wbinvd,
358         .read_msr = native_read_msr_safe,
359         .write_msr = native_write_msr_safe,
360         .read_tsc = native_read_tsc,
361         .read_pmc = native_read_pmc,
362         .read_tscp = native_read_tscp,
363         .load_tr_desc = native_load_tr_desc,
364         .set_ldt = native_set_ldt,
365         .load_gdt = native_load_gdt,
366         .load_idt = native_load_idt,
367         .store_idt = native_store_idt,
368         .store_tr = native_store_tr,
369         .load_tls = native_load_tls,
370 #ifdef CONFIG_X86_64
371         .load_gs_index = native_load_gs_index,
372 #endif
373         .write_ldt_entry = native_write_ldt_entry,
374         .write_gdt_entry = native_write_gdt_entry,
375         .write_idt_entry = native_write_idt_entry,
376 
377         .alloc_ldt = paravirt_nop,
378         .free_ldt = paravirt_nop,
379 
380         .load_sp0 = native_load_sp0,
381 
382 #if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)
383         .irq_enable_sysexit = native_irq_enable_sysexit,
384 #endif
385 #ifdef CONFIG_X86_64
386 #ifdef CONFIG_IA32_EMULATION
387         .usergs_sysret32 = native_usergs_sysret32,
388 #endif
389         .usergs_sysret64 = native_usergs_sysret64,
390 #endif
391         .iret = native_iret,
392         .swapgs = native_swapgs,
393 
394         .set_iopl_mask = native_set_iopl_mask,
395         .io_delay = native_io_delay,
396 
397         .start_context_switch = paravirt_nop,
398         .end_context_switch = paravirt_nop,
399 };
400 
401 /* At this point, native_get/set_debugreg has real function entries */
402 NOKPROBE_SYMBOL(native_get_debugreg);
403 NOKPROBE_SYMBOL(native_set_debugreg);
404 NOKPROBE_SYMBOL(native_load_idt);
405 
406 struct pv_apic_ops pv_apic_ops = {
407 #ifdef CONFIG_X86_LOCAL_APIC
408         .startup_ipi_hook = paravirt_nop,
409 #endif
410 };
411 
412 #if defined(CONFIG_X86_32) && !defined(CONFIG_X86_PAE)
413 /* 32-bit pagetable entries */
414 #define PTE_IDENT       __PV_IS_CALLEE_SAVE(_paravirt_ident_32)
415 #else
416 /* 64-bit pagetable entries */
417 #define PTE_IDENT       __PV_IS_CALLEE_SAVE(_paravirt_ident_64)
418 #endif
419 
420 struct pv_mmu_ops pv_mmu_ops = {
421 
422         .read_cr2 = native_read_cr2,
423         .write_cr2 = native_write_cr2,
424         .read_cr3 = native_read_cr3,
425         .write_cr3 = native_write_cr3,
426 
427         .flush_tlb_user = native_flush_tlb,
428         .flush_tlb_kernel = native_flush_tlb_global,
429         .flush_tlb_single = native_flush_tlb_single,
430         .flush_tlb_others = native_flush_tlb_others,
431 
432         .pgd_alloc = __paravirt_pgd_alloc,
433         .pgd_free = paravirt_nop,
434 
435         .alloc_pte = paravirt_nop,
436         .alloc_pmd = paravirt_nop,
437         .alloc_pud = paravirt_nop,
438         .release_pte = paravirt_nop,
439         .release_pmd = paravirt_nop,
440         .release_pud = paravirt_nop,
441 
442         .set_pte = native_set_pte,
443         .set_pte_at = native_set_pte_at,
444         .set_pmd = native_set_pmd,
445         .set_pmd_at = native_set_pmd_at,
446         .pte_update = paravirt_nop,
447         .pte_update_defer = paravirt_nop,
448         .pmd_update = paravirt_nop,
449         .pmd_update_defer = paravirt_nop,
450 
451         .ptep_modify_prot_start = __ptep_modify_prot_start,
452         .ptep_modify_prot_commit = __ptep_modify_prot_commit,
453 
454 #if PAGETABLE_LEVELS >= 3
455 #ifdef CONFIG_X86_PAE
456         .set_pte_atomic = native_set_pte_atomic,
457         .pte_clear = native_pte_clear,
458         .pmd_clear = native_pmd_clear,
459 #endif
460         .set_pud = native_set_pud,
461 
462         .pmd_val = PTE_IDENT,
463         .make_pmd = PTE_IDENT,
464 
465 #if PAGETABLE_LEVELS == 4
466         .pud_val = PTE_IDENT,
467         .make_pud = PTE_IDENT,
468 
469         .set_pgd = native_set_pgd,
470 #endif
471 #endif /* PAGETABLE_LEVELS >= 3 */
472 
473         .pte_val = PTE_IDENT,
474         .pgd_val = PTE_IDENT,
475 
476         .make_pte = PTE_IDENT,
477         .make_pgd = PTE_IDENT,
478 
479         .dup_mmap = paravirt_nop,
480         .exit_mmap = paravirt_nop,
481         .activate_mm = paravirt_nop,
482 
483         .lazy_mode = {
484                 .enter = paravirt_nop,
485                 .leave = paravirt_nop,
486                 .flush = paravirt_nop,
487         },
488 
489         .set_fixmap = native_set_fixmap,
490 };
491 
492 EXPORT_SYMBOL_GPL(pv_time_ops);
493 EXPORT_SYMBOL    (pv_cpu_ops);
494 EXPORT_SYMBOL    (pv_mmu_ops);
495 EXPORT_SYMBOL_GPL(pv_apic_ops);
496 EXPORT_SYMBOL_GPL(pv_info);
497 EXPORT_SYMBOL    (pv_irq_ops);
498 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp