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                 .pv_lock_ops = pv_lock_ops,
 138         };
 139         return *((void **)&tmpl + type);
 140 }
 141
 142 unsigned paravirt_patch_default(u8 type, u16 clobbers, void *insnbuf,
 143                                 unsigned long addr, unsigned len)
 144 {
 145         void *opfunc = get_call_destination(type);
 146         unsigned ret;
 147
 148         if (opfunc == NULL)
 149                 /* If there's no function, patch it with a ud2a (BUG) */
 150                 ret = paravirt_patch_insns(insnbuf, len, ud2a, ud2a+sizeof(ud2a));
 151         else if (opfunc == _paravirt_nop)
 152                 /* If the operation is a nop, then nop the callsite */
 153                 ret = paravirt_patch_nop();
 154
 155         /* identity functions just return their single argument */
 156         else if (opfunc == _paravirt_ident_32)
 157                 ret = paravirt_patch_ident_32(insnbuf, len);
 158         else if (opfunc == _paravirt_ident_64)
 159                 ret = paravirt_patch_ident_64(insnbuf, len);
 160
 161         else if (type == PARAVIRT_PATCH(pv_cpu_ops.iret) ||
 162                  type == PARAVIRT_PATCH(pv_cpu_ops.irq_enable_sysexit) ||
 163                  type == PARAVIRT_PATCH(pv_cpu_ops.usergs_sysret32) ||
 164                  type == PARAVIRT_PATCH(pv_cpu_ops.usergs_sysret64))
 165                 /* If operation requires a jmp, then jmp */
 166                 ret = paravirt_patch_jmp(insnbuf, opfunc, addr, len);
 167         else
 168                 /* Otherwise call the function; assume target could
 169                    clobber any caller-save reg */
 170                 ret = paravirt_patch_call(insnbuf, opfunc, CLBR_ANY,
 171                                           addr, clobbers, len);
 172
 173         return ret;
 174 }
 175
 176 unsigned paravirt_patch_insns(void *insnbuf, unsigned len,
 177                               const char *start, const char *end)
 178 {
 179         unsigned insn_len = end - start;
 180
 181         if (insn_len > len || start == NULL)
 182                 insn_len = len;
 183         else
 184                 memcpy(insnbuf, start, insn_len);
 185
 186         return insn_len;
 187 }
 188
 189 void init_IRQ(void)
 190 {
 191         pv_irq_ops.init_IRQ();
 192 }
 193
 194 static void native_flush_tlb(void)
 195 {
 196         __native_flush_tlb();
 197 }
 198
 199 /*
 200  * Global pages have to be flushed a bit differently. Not a real
 201  * performance problem because this does not happen often.
 202  */
 203 static void native_flush_tlb_global(void)
 204 {
 205         __native_flush_tlb_global();
 206 }
 207
 208 static void native_flush_tlb_single(unsigned long addr)
 209 {
 210         __native_flush_tlb_single(addr);
 211 }
 212
 213 /* These are in entry.S */
 214 extern void native_iret(void);
 215 extern void native_irq_enable_sysexit(void);
 216 extern void native_usergs_sysret32(void);
 217 extern void native_usergs_sysret64(void);
 218
 219 static int __init print_banner(void)
 220 {
 221         pv_init_ops.banner();
 222         return 0;
 223 }
 224 core_initcall(print_banner);
 225
 226 static struct resource reserve_ioports = {
 227         .start = 0,
 228         .end = IO_SPACE_LIMIT,
 229         .name = "paravirt-ioport",
 230         .flags = IORESOURCE_IO | IORESOURCE_BUSY,
 231 };
 232
 233 /*
 234  * Reserve the whole legacy IO space to prevent any legacy drivers
 235  * from wasting time probing for their hardware.  This is a fairly
 236  * brute-force approach to disabling all non-virtual drivers.
 237  *
 238  * Note that this must be called very early to have any effect.
 239  */
 240 int paravirt_disable_iospace(void)
 241 {
 242         return request_resource(&ioport_resource, &reserve_ioports);
 243 }
 244
 245 static DEFINE_PER_CPU(enum paravirt_lazy_mode, paravirt_lazy_mode) = PARAVIRT_LAZY_NONE;
 246
 247 static inline void enter_lazy(enum paravirt_lazy_mode mode)
 248 {
 249         BUG_ON(__get_cpu_var(paravirt_lazy_mode) != PARAVIRT_LAZY_NONE);
 250         BUG_ON(preemptible());
 251
 252         __get_cpu_var(paravirt_lazy_mode) = mode;
 253 }
 254
 255 static void leave_lazy(enum paravirt_lazy_mode mode)
 256 {
 257         BUG_ON(__get_cpu_var(paravirt_lazy_mode) != mode);
 258         BUG_ON(preemptible());
 259
 260         __get_cpu_var(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         if (percpu_read(paravirt_lazy_mode) == PARAVIRT_LAZY_MMU) {
 276                 arch_leave_lazy_mmu_mode();
 277                 set_ti_thread_flag(task_thread_info(prev), TIF_LAZY_MMU_UPDATES);
 278         }
 279         enter_lazy(PARAVIRT_LAZY_CPU);
 280 }
 281
 282 void paravirt_end_context_switch(struct task_struct *next)
 283 {
 284         leave_lazy(PARAVIRT_LAZY_CPU);
 285
 286         if (test_and_clear_ti_thread_flag(task_thread_info(next), TIF_LAZY_MMU_UPDATES))
 287                 arch_enter_lazy_mmu_mode();
 288 }
 289
 290 enum paravirt_lazy_mode paravirt_get_lazy_mode(void)
 291 {
 292         if (in_interrupt())
 293                 return PARAVIRT_LAZY_NONE;
 294
 295         return __get_cpu_var(paravirt_lazy_mode);
 296 }
 297
 298 void arch_flush_lazy_mmu_mode(void)
 299 {
 300         preempt_disable();
 301
 302         if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) {
 303                 WARN_ON(preempt_count() == 1);
 304                 arch_leave_lazy_mmu_mode();
 305                 arch_enter_lazy_mmu_mode();
 306         }
 307
 308         preempt_enable();
 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
 318 struct pv_init_ops pv_init_ops = {
 319         .patch = native_patch,
 320         .banner = default_banner,
 321         .arch_setup = paravirt_nop,
 322         .memory_setup = machine_specific_memory_setup,
 323 };
 324
 325 struct pv_time_ops pv_time_ops = {
 326         .time_init = hpet_time_init,
 327         .get_wallclock = native_get_wallclock,
 328         .set_wallclock = native_set_wallclock,
 329         .sched_clock = native_sched_clock,
 330         .get_tsc_khz = native_calibrate_tsc,
 331 };
 332
 333 struct pv_irq_ops pv_irq_ops = {
 334         .init_IRQ = native_init_IRQ,
 335         .save_fl = __PV_IS_CALLEE_SAVE(native_save_fl),
 336         .restore_fl = __PV_IS_CALLEE_SAVE(native_restore_fl),
 337         .irq_disable = __PV_IS_CALLEE_SAVE(native_irq_disable),
 338         .irq_enable = __PV_IS_CALLEE_SAVE(native_irq_enable),
 339         .safe_halt = native_safe_halt,
 340         .halt = native_halt,
 341 #ifdef CONFIG_X86_64
 342         .adjust_exception_frame = paravirt_nop,
 343 #endif
 344 };
 345
 346 struct pv_cpu_ops pv_cpu_ops = {
 347         .cpuid = native_cpuid,
 348         .get_debugreg = native_get_debugreg,
 349         .set_debugreg = native_set_debugreg,
 350         .clts = native_clts,
 351         .read_cr0 = native_read_cr0,
 352         .write_cr0 = native_write_cr0,
 353         .read_cr4 = native_read_cr4,
 354         .read_cr4_safe = native_read_cr4_safe,
 355         .write_cr4 = native_write_cr4,
 356 #ifdef CONFIG_X86_64
 357         .read_cr8 = native_read_cr8,
 358         .write_cr8 = native_write_cr8,
 359 #endif
 360         .wbinvd = native_wbinvd,
 361         .read_msr = native_read_msr_safe,
 362         .read_msr_amd = native_read_msr_amd_safe,
 363         .write_msr = native_write_msr_safe,
 364         .read_tsc = native_read_tsc,
 365         .read_pmc = native_read_pmc,
 366         .read_tscp = native_read_tscp,
 367         .load_tr_desc = native_load_tr_desc,
 368         .set_ldt = native_set_ldt,
 369         .load_gdt = native_load_gdt,
 370         .load_idt = native_load_idt,
 371         .store_gdt = native_store_gdt,
 372         .store_idt = native_store_idt,
 373         .store_tr = native_store_tr,
 374         .load_tls = native_load_tls,
 375 #ifdef CONFIG_X86_64
 376         .load_gs_index = native_load_gs_index,
 377 #endif
 378         .write_ldt_entry = native_write_ldt_entry,
 379         .write_gdt_entry = native_write_gdt_entry,
 380         .write_idt_entry = native_write_idt_entry,
 381
 382         .alloc_ldt = paravirt_nop,
 383         .free_ldt = paravirt_nop,
 384
 385         .load_sp0 = native_load_sp0,
 386
 387 #if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)
 388         .irq_enable_sysexit = native_irq_enable_sysexit,
 389 #endif
 390 #ifdef CONFIG_X86_64
 391 #ifdef CONFIG_IA32_EMULATION
 392         .usergs_sysret32 = native_usergs_sysret32,
 393 #endif
 394         .usergs_sysret64 = native_usergs_sysret64,
 395 #endif
 396         .iret = native_iret,
 397         .swapgs = native_swapgs,
 398
 399         .set_iopl_mask = native_set_iopl_mask,
 400         .io_delay = native_io_delay,
 401
 402         .start_context_switch = paravirt_nop,
 403         .end_context_switch = paravirt_nop,
 404 };
 405
 406 struct pv_apic_ops pv_apic_ops = {
 407 #ifdef CONFIG_X86_LOCAL_APIC
 408         .setup_boot_clock = setup_boot_APIC_clock,
 409         .setup_secondary_clock = setup_secondary_APIC_clock,
 410         .startup_ipi_hook = paravirt_nop,
 411 #endif
 412 };
 413
 414 #if defined(CONFIG_X86_32) && !defined(CONFIG_X86_PAE)
 415 /* 32-bit pagetable entries */
 416 #define PTE_IDENT       __PV_IS_CALLEE_SAVE(_paravirt_ident_32)
 417 #else
 418 /* 64-bit pagetable entries */
 419 #define PTE_IDENT       __PV_IS_CALLEE_SAVE(_paravirt_ident_64)
 420 #endif
 421
 422 struct pv_mmu_ops pv_mmu_ops = {
 423 #ifndef CONFIG_X86_64
 424         .pagetable_setup_start = native_pagetable_setup_start,
 425         .pagetable_setup_done = native_pagetable_setup_done,
 426 #else
 427         .pagetable_setup_start = paravirt_nop,
 428         .pagetable_setup_done = paravirt_nop,
 429 #endif
 430
 431         .read_cr2 = native_read_cr2,
 432         .write_cr2 = native_write_cr2,
 433         .read_cr3 = native_read_cr3,
 434         .write_cr3 = native_write_cr3,
 435
 436         .flush_tlb_user = native_flush_tlb,
 437         .flush_tlb_kernel = native_flush_tlb_global,
 438         .flush_tlb_single = native_flush_tlb_single,
 439         .flush_tlb_others = native_flush_tlb_others,
 440
 441         .pgd_alloc = __paravirt_pgd_alloc,
 442         .pgd_free = paravirt_nop,
 443
 444         .alloc_pte = paravirt_nop,
 445         .alloc_pmd = paravirt_nop,
 446         .alloc_pmd_clone = paravirt_nop,
 447         .alloc_pud = paravirt_nop,
 448         .release_pte = paravirt_nop,
 449         .release_pmd = paravirt_nop,
 450         .release_pud = paravirt_nop,
 451
 452         .set_pte = native_set_pte,
 453         .set_pte_at = native_set_pte_at,
 454         .set_pmd = native_set_pmd,
 455         .pte_update = paravirt_nop,
 456         .pte_update_defer = paravirt_nop,
 457
 458         .ptep_modify_prot_start = __ptep_modify_prot_start,
 459         .ptep_modify_prot_commit = __ptep_modify_prot_commit,
 460
 461 #ifdef CONFIG_HIGHPTE
 462         .kmap_atomic_pte = kmap_atomic,
 463 #endif
 464
 465 #if PAGETABLE_LEVELS >= 3
 466 #ifdef CONFIG_X86_PAE
 467         .set_pte_atomic = native_set_pte_atomic,
 468         .set_pte_present = native_set_pte_present,
 469         .pte_clear = native_pte_clear,
 470         .pmd_clear = native_pmd_clear,
 471 #endif
 472         .set_pud = native_set_pud,
 473
 474         .pmd_val = PTE_IDENT,
 475         .make_pmd = PTE_IDENT,
 476
 477 #if PAGETABLE_LEVELS == 4
 478         .pud_val = PTE_IDENT,
 479         .make_pud = PTE_IDENT,
 480
 481         .set_pgd = native_set_pgd,
 482 #endif
 483 #endif /* PAGETABLE_LEVELS >= 3 */
 484
 485         .pte_val = PTE_IDENT,
 486         .pgd_val = PTE_IDENT,
 487
 488         .make_pte = PTE_IDENT,
 489         .make_pgd = PTE_IDENT,
 490
 491         .dup_mmap = paravirt_nop,
 492         .exit_mmap = paravirt_nop,
 493         .activate_mm = paravirt_nop,
 494
 495         .lazy_mode = {
 496                 .enter = paravirt_nop,
 497                 .leave = paravirt_nop,
 498         },
 499
 500         .set_fixmap = native_set_fixmap,
 501 };
 502
 503 EXPORT_SYMBOL_GPL(pv_time_ops);
 504 EXPORT_SYMBOL    (pv_cpu_ops);
 505 EXPORT_SYMBOL    (pv_mmu_ops);
 506 EXPORT_SYMBOL_GPL(pv_apic_ops);
 507 EXPORT_SYMBOL_GPL(pv_info);
 508 EXPORT_SYMBOL    (pv_irq_ops);