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/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 */
  42 void _paravirt_nop(void)
  43 {
  44 }
  45
  46 /* identity function, which can be inlined */
  47 u32 _paravirt_ident_32(u32 x)
  48 {
  49         return x;
  50 }
  51
  52 u64 _paravirt_ident_64(u64 x)
  53 {
  54         return x;
  55 }
  56
  57 static void __init default_banner(void)
  58 {
  59         printk(KERN_INFO "Booting paravirtualized kernel on %s\n",
  60                pv_info.name);
  61 }
  62
  63 char *memory_setup(void)
  64 {
  65         return pv_init_ops.memory_setup();
  66 }
  67
  68 /* Simple instruction patching code. */
  69 #define DEF_NATIVE(ops, name, code)                                     \
  70         extern const char start_##ops##_##name[], end_##ops##_##name[]; \
  71         asm("start_" #ops "_" #name ": " code "; end_" #ops "_" #name ":")
  72
  73 /* Undefined instruction for dealing with missing ops pointers. */
  74 static const unsigned char ud2a[] = { 0x0f, 0x0b };
  75
  76 unsigned paravirt_patch_nop(void)
  77 {
  78         return 0;
  79 }
  80
  81 unsigned paravirt_patch_ignore(unsigned len)
  82 {
  83         return len;
  84 }
  85
  86 struct branch {
  87         unsigned char opcode;
  88         u32 delta;
  89 } __attribute__((packed));
  90
  91 unsigned paravirt_patch_call(void *insnbuf,
  92                              const void *target, u16 tgt_clobbers,
  93                              unsigned long addr, u16 site_clobbers,
  94                              unsigned len)
  95 {
  96         struct branch *b = insnbuf;
  97         unsigned long delta = (unsigned long)target - (addr+5);
  98
  99         if (tgt_clobbers & ~site_clobbers)
 100                 return len;     /* target would clobber too much for this site */
 101         if (len < 5)
 102                 return len;     /* call too long for patch site */
 103
 104         b->opcode = 0xe8; /* call */
 105         b->delta = delta;
 106         BUILD_BUG_ON(sizeof(*b) != 5);
 107
 108         return 5;
 109 }
 110
 111 unsigned paravirt_patch_jmp(void *insnbuf, const void *target,
 112                             unsigned long addr, unsigned len)
 113 {
 114         struct branch *b = insnbuf;
 115         unsigned long delta = (unsigned long)target - (addr+5);
 116
 117         if (len < 5)
 118                 return len;     /* call too long for patch site */
 119
 120         b->opcode = 0xe9;       /* jmp */
 121         b->delta = delta;
 122
 123         return 5;
 124 }
 125
 126 /* Neat trick to map patch type back to the call within the
 127  * corresponding structure. */
 128 static void *get_call_destination(u8 type)
 129 {
 130         struct paravirt_patch_template tmpl = {
 131                 .pv_init_ops = pv_init_ops,
 132                 .pv_time_ops = pv_time_ops,
 133                 .pv_cpu_ops = pv_cpu_ops,
 134                 .pv_irq_ops = pv_irq_ops,
 135                 .pv_apic_ops = pv_apic_ops,
 136                 .pv_mmu_ops = pv_mmu_ops,
 137 #ifdef CONFIG_PARAVIRT_SPINLOCKS
 138                 .pv_lock_ops = pv_lock_ops,
 139 #endif
 140         };
 141         return *((void **)&tmpl + type);
 142 }
 143
 144 unsigned paravirt_patch_default(u8 type, u16 clobbers, void *insnbuf,
 145                                 unsigned long addr, unsigned len)
 146 {
 147         void *opfunc = get_call_destination(type);
 148         unsigned ret;
 149
 150         if (opfunc == NULL)
 151                 /* If there's no function, patch it with a ud2a (BUG) */
 152                 ret = paravirt_patch_insns(insnbuf, len, ud2a, ud2a+sizeof(ud2a));
 153         else if (opfunc == _paravirt_nop)
 154                 /* If the operation is a nop, then nop the callsite */
 155                 ret = paravirt_patch_nop();
 156
 157         /* identity functions just return their single argument */
 158         else if (opfunc == _paravirt_ident_32)
 159                 ret = paravirt_patch_ident_32(insnbuf, len);
 160         else if (opfunc == _paravirt_ident_64)
 161                 ret = paravirt_patch_ident_64(insnbuf, len);
 162
 163         else if (type == PARAVIRT_PATCH(pv_cpu_ops.iret) ||
 164                  type == PARAVIRT_PATCH(pv_cpu_ops.irq_enable_sysexit) ||
 165                  type == PARAVIRT_PATCH(pv_cpu_ops.usergs_sysret32) ||
 166                  type == PARAVIRT_PATCH(pv_cpu_ops.usergs_sysret64))
 167                 /* If operation requires a jmp, then jmp */
 168                 ret = paravirt_patch_jmp(insnbuf, opfunc, addr, len);
 169         else
 170                 /* Otherwise call the function; assume target could
 171                    clobber any caller-save reg */
 172                 ret = paravirt_patch_call(insnbuf, opfunc, CLBR_ANY,
 173                                           addr, clobbers, len);
 174
 175         return ret;
 176 }
 177
 178 unsigned paravirt_patch_insns(void *insnbuf, unsigned len,
 179                               const char *start, const char *end)
 180 {
 181         unsigned insn_len = end - start;
 182
 183         if (insn_len > len || start == NULL)
 184                 insn_len = len;
 185         else
 186                 memcpy(insnbuf, start, insn_len);
 187
 188         return insn_len;
 189 }
 190
 191 void init_IRQ(void)
 192 {
 193         pv_irq_ops.init_IRQ();
 194 }
 195
 196 static void native_flush_tlb(void)
 197 {
 198         __native_flush_tlb();
 199 }
 200
 201 /*
 202  * Global pages have to be flushed a bit differently. Not a real
 203  * performance problem because this does not happen often.
 204  */
 205 static void native_flush_tlb_global(void)
 206 {
 207         __native_flush_tlb_global();
 208 }
 209
 210 static void native_flush_tlb_single(unsigned long addr)
 211 {
 212         __native_flush_tlb_single(addr);
 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 int __init print_banner(void)
 222 {
 223         pv_init_ops.banner();
 224         return 0;
 225 }
 226 core_initcall(print_banner);
 227
 228 static struct resource reserve_ioports = {
 229         .start = 0,
 230         .end = IO_SPACE_LIMIT,
 231         .name = "paravirt-ioport",
 232         .flags = IORESOURCE_IO | IORESOURCE_BUSY,
 233 };
 234
 235 /*
 236  * Reserve the whole legacy IO space to prevent any legacy drivers
 237  * from wasting time probing for their hardware.  This is a fairly
 238  * brute-force approach to disabling all non-virtual drivers.
 239  *
 240  * Note that this must be called very early to have any effect.
 241  */
 242 int paravirt_disable_iospace(void)
 243 {
 244         return request_resource(&ioport_resource, &reserve_ioports);
 245 }
 246
 247 static DEFINE_PER_CPU(enum paravirt_lazy_mode, paravirt_lazy_mode) = PARAVIRT_LAZY_NONE;
 248
 249 static inline void enter_lazy(enum paravirt_lazy_mode mode)
 250 {
 251         BUG_ON(percpu_read(paravirt_lazy_mode) != PARAVIRT_LAZY_NONE);
 252
 253         percpu_write(paravirt_lazy_mode, mode);
 254 }
 255
 256 static void leave_lazy(enum paravirt_lazy_mode mode)
 257 {
 258         BUG_ON(percpu_read(paravirt_lazy_mode) != mode);
 259
 260         percpu_write(paravirt_lazy_mode, PARAVIRT_LAZY_NONE);
 261 }
 262
 263 void paravirt_enter_lazy_mmu(void)
 264 {
 265         enter_lazy(PARAVIRT_LAZY_MMU);
 266 }
 267
 268 void paravirt_leave_lazy_mmu(void)
 269 {
 270         leave_lazy(PARAVIRT_LAZY_MMU);
 271 }
 272
 273 void paravirt_start_context_switch(struct task_struct *prev)
 274 {
 275         BUG_ON(preemptible());
 276
 277         if (percpu_read(paravirt_lazy_mode) == PARAVIRT_LAZY_MMU) {
 278                 arch_leave_lazy_mmu_mode();
 279                 set_ti_thread_flag(task_thread_info(prev), TIF_LAZY_MMU_UPDATES);
 280         }
 281         enter_lazy(PARAVIRT_LAZY_CPU);
 282 }
 283
 284 void paravirt_end_context_switch(struct task_struct *next)
 285 {
 286         BUG_ON(preemptible());
 287
 288         leave_lazy(PARAVIRT_LAZY_CPU);
 289
 290         if (test_and_clear_ti_thread_flag(task_thread_info(next), TIF_LAZY_MMU_UPDATES))
 291                 arch_enter_lazy_mmu_mode();
 292 }
 293
 294 enum paravirt_lazy_mode paravirt_get_lazy_mode(void)
 295 {
 296         if (in_interrupt())
 297                 return PARAVIRT_LAZY_NONE;
 298
 299         return percpu_read(paravirt_lazy_mode);
 300 }
 301
 302 void arch_flush_lazy_mmu_mode(void)
 303 {
 304         preempt_disable();
 305
 306         if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) {
 307                 arch_leave_lazy_mmu_mode();
 308                 arch_enter_lazy_mmu_mode();
 309         }
 310
 311         preempt_enable();
 312 }
 313
 314 struct pv_info pv_info = {
 315         .name = "bare hardware",
 316         .paravirt_enabled = 0,
 317         .kernel_rpl = 0,
 318         .shared_kernel_pmd = 1, /* Only used when CONFIG_X86_PAE is set */
 319 };
 320
 321 struct pv_init_ops pv_init_ops = {
 322         .patch = native_patch,
 323         .banner = default_banner,
 324         .arch_setup = paravirt_nop,
 325         .memory_setup = machine_specific_memory_setup,
 326 };
 327
 328 struct pv_time_ops pv_time_ops = {
 329         .time_init = hpet_time_init,
 330         .get_wallclock = native_get_wallclock,
 331         .set_wallclock = native_set_wallclock,
 332         .sched_clock = native_sched_clock,
 333         .get_tsc_khz = native_calibrate_tsc,
 334 };
 335
 336 struct pv_irq_ops pv_irq_ops = {
 337         .init_IRQ = native_init_IRQ,
 338         .save_fl = __PV_IS_CALLEE_SAVE(native_save_fl),
 339         .restore_fl = __PV_IS_CALLEE_SAVE(native_restore_fl),
 340         .irq_disable = __PV_IS_CALLEE_SAVE(native_irq_disable),
 341         .irq_enable = __PV_IS_CALLEE_SAVE(native_irq_enable),
 342         .safe_halt = native_safe_halt,
 343         .halt = native_halt,
 344 #ifdef CONFIG_X86_64
 345         .adjust_exception_frame = paravirt_nop,
 346 #endif
 347 };
 348
 349 struct pv_cpu_ops pv_cpu_ops = {
 350         .cpuid = native_cpuid,
 351         .get_debugreg = native_get_debugreg,
 352         .set_debugreg = native_set_debugreg,
 353         .clts = native_clts,
 354         .read_cr0 = native_read_cr0,
 355         .write_cr0 = native_write_cr0,
 356         .read_cr4 = native_read_cr4,
 357         .read_cr4_safe = native_read_cr4_safe,
 358         .write_cr4 = native_write_cr4,
 359 #ifdef CONFIG_X86_64
 360         .read_cr8 = native_read_cr8,
 361         .write_cr8 = native_write_cr8,
 362 #endif
 363         .wbinvd = native_wbinvd,
 364         .read_msr = native_read_msr_safe,
 365         .read_msr_amd = native_read_msr_amd_safe,
 366         .write_msr = native_write_msr_safe,
 367         .read_tsc = native_read_tsc,
 368         .read_pmc = native_read_pmc,
 369         .read_tscp = native_read_tscp,
 370         .load_tr_desc = native_load_tr_desc,
 371         .set_ldt = native_set_ldt,
 372         .load_gdt = native_load_gdt,
 373         .load_idt = native_load_idt,
 374         .store_gdt = native_store_gdt,
 375         .store_idt = native_store_idt,
 376         .store_tr = native_store_tr,
 377         .load_tls = native_load_tls,
 378 #ifdef CONFIG_X86_64
 379         .load_gs_index = native_load_gs_index,
 380 #endif
 381         .write_ldt_entry = native_write_ldt_entry,
 382         .write_gdt_entry = native_write_gdt_entry,
 383         .write_idt_entry = native_write_idt_entry,
 384
 385         .alloc_ldt = paravirt_nop,
 386         .free_ldt = paravirt_nop,
 387
 388         .load_sp0 = native_load_sp0,
 389
 390 #if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)
 391         .irq_enable_sysexit = native_irq_enable_sysexit,
 392 #endif
 393 #ifdef CONFIG_X86_64
 394 #ifdef CONFIG_IA32_EMULATION
 395         .usergs_sysret32 = native_usergs_sysret32,
 396 #endif
 397         .usergs_sysret64 = native_usergs_sysret64,
 398 #endif
 399         .iret = native_iret,
 400         .swapgs = native_swapgs,
 401
 402         .set_iopl_mask = native_set_iopl_mask,
 403         .io_delay = native_io_delay,
 404
 405         .start_context_switch = paravirt_nop,
 406         .end_context_switch = paravirt_nop,
 407 };
 408
 409 struct pv_apic_ops pv_apic_ops = {
 410 #ifdef CONFIG_X86_LOCAL_APIC
 411         .setup_boot_clock = setup_boot_APIC_clock,
 412         .setup_secondary_clock = setup_secondary_APIC_clock,
 413         .startup_ipi_hook = paravirt_nop,
 414 #endif
 415 };
 416
 417 #if defined(CONFIG_X86_32) && !defined(CONFIG_X86_PAE)
 418 /* 32-bit pagetable entries */
 419 #define PTE_IDENT       __PV_IS_CALLEE_SAVE(_paravirt_ident_32)
 420 #else
 421 /* 64-bit pagetable entries */
 422 #define PTE_IDENT       __PV_IS_CALLEE_SAVE(_paravirt_ident_64)
 423 #endif
 424
 425 struct pv_mmu_ops pv_mmu_ops = {
 426 #ifndef CONFIG_X86_64
 427         .pagetable_setup_start = native_pagetable_setup_start,
 428         .pagetable_setup_done = native_pagetable_setup_done,
 429 #else
 430         .pagetable_setup_start = paravirt_nop,
 431         .pagetable_setup_done = paravirt_nop,
 432 #endif
 433
 434         .read_cr2 = native_read_cr2,
 435         .write_cr2 = native_write_cr2,
 436         .read_cr3 = native_read_cr3,
 437         .write_cr3 = native_write_cr3,
 438
 439         .flush_tlb_user = native_flush_tlb,
 440         .flush_tlb_kernel = native_flush_tlb_global,
 441         .flush_tlb_single = native_flush_tlb_single,
 442         .flush_tlb_others = native_flush_tlb_others,
 443
 444         .pgd_alloc = __paravirt_pgd_alloc,
 445         .pgd_free = paravirt_nop,
 446
 447         .alloc_pte = paravirt_nop,
 448         .alloc_pmd = paravirt_nop,
 449         .alloc_pmd_clone = paravirt_nop,
 450         .alloc_pud = paravirt_nop,
 451         .release_pte = paravirt_nop,
 452         .release_pmd = paravirt_nop,
 453         .release_pud = paravirt_nop,
 454
 455         .set_pte = native_set_pte,
 456         .set_pte_at = native_set_pte_at,
 457         .set_pmd = native_set_pmd,
 458         .pte_update = paravirt_nop,
 459         .pte_update_defer = paravirt_nop,
 460
 461         .ptep_modify_prot_start = __ptep_modify_prot_start,
 462         .ptep_modify_prot_commit = __ptep_modify_prot_commit,
 463
 464 #ifdef CONFIG_HIGHPTE
 465         .kmap_atomic_pte = kmap_atomic,
 466 #endif
 467
 468 #if PAGETABLE_LEVELS >= 3
 469 #ifdef CONFIG_X86_PAE
 470         .set_pte_atomic = native_set_pte_atomic,
 471         .pte_clear = native_pte_clear,
 472         .pmd_clear = native_pmd_clear,
 473 #endif
 474         .set_pud = native_set_pud,
 475
 476         .pmd_val = PTE_IDENT,
 477         .make_pmd = PTE_IDENT,
 478
 479 #if PAGETABLE_LEVELS == 4
 480         .pud_val = PTE_IDENT,
 481         .make_pud = PTE_IDENT,
 482
 483         .set_pgd = native_set_pgd,
 484 #endif
 485 #endif /* PAGETABLE_LEVELS >= 3 */
 486
 487         .pte_val = PTE_IDENT,
 488         .pgd_val = PTE_IDENT,
 489
 490         .make_pte = PTE_IDENT,
 491         .make_pgd = PTE_IDENT,
 492
 493         .dup_mmap = paravirt_nop,
 494         .exit_mmap = paravirt_nop,
 495         .activate_mm = paravirt_nop,
 496
 497         .lazy_mode = {
 498                 .enter = paravirt_nop,
 499                 .leave = paravirt_nop,
 500         },
 501
 502         .set_fixmap = native_set_fixmap,
 503 };
 504
 505 EXPORT_SYMBOL_GPL(pv_time_ops);
 506 EXPORT_SYMBOL    (pv_cpu_ops);
 507 EXPORT_SYMBOL    (pv_mmu_ops);
 508 EXPORT_SYMBOL_GPL(pv_apic_ops);
 509 EXPORT_SYMBOL_GPL(pv_info);
 510 EXPORT_SYMBOL    (pv_irq_ops);