arch/x86/kernel/paravirt_32.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 #include <linux/errno.h>
  19 #include <linux/module.h>
  20 #include <linux/efi.h>
  21 #include <linux/bcd.h>
  22 #include <linux/highmem.h>
  23
  24 #include <asm/bug.h>
  25 #include <asm/paravirt.h>
  26 #include <asm/desc.h>
  27 #include <asm/setup.h>
  28 #include <asm/arch_hooks.h>
  29 #include <asm/time.h>
  30 #include <asm/irq.h>
  31 #include <asm/delay.h>
  32 #include <asm/fixmap.h>
  33 #include <asm/apic.h>
  34 #include <asm/tlbflush.h>
  35 #include <asm/timer.h>
  36
  37 /* nop stub */
  38 void _paravirt_nop(void)
  39 {
  40 }
  41
  42 static void __init default_banner(void)
  43 {
  44         printk(KERN_INFO "Booting paravirtualized kernel on %s\n",
  45                pv_info.name);
  46 }
  47
  48 char *memory_setup(void)
  49 {
  50         return pv_init_ops.memory_setup();
  51 }
  52
  53 /* Simple instruction patching code. */
  54 #define DEF_NATIVE(ops, name, code)                                     \
  55         extern const char start_##ops##_##name[], end_##ops##_##name[]; \
  56         asm("start_" #ops "_" #name ": " code "; end_" #ops "_" #name ":")
  57
  58 DEF_NATIVE(pv_irq_ops, irq_disable, "cli");
  59 DEF_NATIVE(pv_irq_ops, irq_enable, "sti");
  60 DEF_NATIVE(pv_irq_ops, restore_fl, "push %eax; popf");
  61 DEF_NATIVE(pv_irq_ops, save_fl, "pushf; pop %eax");
  62 DEF_NATIVE(pv_cpu_ops, iret, "iret");
  63 DEF_NATIVE(pv_cpu_ops, irq_enable_syscall_ret, "sti; sysexit");
  64 DEF_NATIVE(pv_mmu_ops, read_cr2, "mov %cr2, %eax");
  65 DEF_NATIVE(pv_mmu_ops, write_cr3, "mov %eax, %cr3");
  66 DEF_NATIVE(pv_mmu_ops, read_cr3, "mov %cr3, %eax");
  67 DEF_NATIVE(pv_cpu_ops, clts, "clts");
  68 DEF_NATIVE(pv_cpu_ops, read_tsc, "rdtsc");
  69
  70 /* Undefined instruction for dealing with missing ops pointers. */
  71 static const unsigned char ud2a[] = { 0x0f, 0x0b };
  72
  73 static unsigned native_patch(u8 type, u16 clobbers, void *ibuf,
  74                              unsigned long addr, unsigned len)
  75 {
  76         const unsigned char *start, *end;
  77         unsigned ret;
  78
  79         switch(type) {
  80 #define SITE(ops, x)                                            \
  81         case PARAVIRT_PATCH(ops.x):                             \
  82                 start = start_##ops##_##x;                      \
  83                 end = end_##ops##_##x;                          \
  84                 goto patch_site
  85
  86         SITE(pv_irq_ops, irq_disable);
  87         SITE(pv_irq_ops, irq_enable);
  88         SITE(pv_irq_ops, restore_fl);
  89         SITE(pv_irq_ops, save_fl);
  90         SITE(pv_cpu_ops, iret);
  91         SITE(pv_cpu_ops, irq_enable_syscall_ret);
  92         SITE(pv_mmu_ops, read_cr2);
  93         SITE(pv_mmu_ops, read_cr3);
  94         SITE(pv_mmu_ops, write_cr3);
  95         SITE(pv_cpu_ops, clts);
  96         SITE(pv_cpu_ops, read_tsc);
  97 #undef SITE
  98
  99         patch_site:
 100                 ret = paravirt_patch_insns(ibuf, len, start, end);
 101                 break;
 102
 103         default:
 104                 ret = paravirt_patch_default(type, clobbers, ibuf, addr, len);
 105                 break;
 106         }
 107
 108         return ret;
 109 }
 110
 111 unsigned paravirt_patch_nop(void)
 112 {
 113         return 0;
 114 }
 115
 116 unsigned paravirt_patch_ignore(unsigned len)
 117 {
 118         return len;
 119 }
 120
 121 struct branch {
 122         unsigned char opcode;
 123         u32 delta;
 124 } __attribute__((packed));
 125
 126 unsigned paravirt_patch_call(void *insnbuf,
 127                              const void *target, u16 tgt_clobbers,
 128                              unsigned long addr, u16 site_clobbers,
 129                              unsigned len)
 130 {
 131         struct branch *b = insnbuf;
 132         unsigned long delta = (unsigned long)target - (addr+5);
 133
 134         if (tgt_clobbers & ~site_clobbers)
 135                 return len;     /* target would clobber too much for this site */
 136         if (len < 5)
 137                 return len;     /* call too long for patch site */
 138
 139         b->opcode = 0xe8; /* call */
 140         b->delta = delta;
 141         BUILD_BUG_ON(sizeof(*b) != 5);
 142
 143         return 5;
 144 }
 145
 146 unsigned paravirt_patch_jmp(void *insnbuf, const void *target,
 147                             unsigned long addr, unsigned len)
 148 {
 149         struct branch *b = insnbuf;
 150         unsigned long delta = (unsigned long)target - (addr+5);
 151
 152         if (len < 5)
 153                 return len;     /* call too long for patch site */
 154
 155         b->opcode = 0xe9;       /* jmp */
 156         b->delta = delta;
 157
 158         return 5;
 159 }
 160
 161 /* Neat trick to map patch type back to the call within the
 162  * corresponding structure. */
 163 static void *get_call_destination(u8 type)
 164 {
 165         struct paravirt_patch_template tmpl = {
 166                 .pv_init_ops = pv_init_ops,
 167                 .pv_time_ops = pv_time_ops,
 168                 .pv_cpu_ops = pv_cpu_ops,
 169                 .pv_irq_ops = pv_irq_ops,
 170                 .pv_apic_ops = pv_apic_ops,
 171                 .pv_mmu_ops = pv_mmu_ops,
 172         };
 173         return *((void **)&tmpl + type);
 174 }
 175
 176 unsigned paravirt_patch_default(u8 type, u16 clobbers, void *insnbuf,
 177                                 unsigned long addr, unsigned len)
 178 {
 179         void *opfunc = get_call_destination(type);
 180         unsigned ret;
 181
 182         if (opfunc == NULL)
 183                 /* If there's no function, patch it with a ud2a (BUG) */
 184                 ret = paravirt_patch_insns(insnbuf, len, ud2a, ud2a+sizeof(ud2a));
 185         else if (opfunc == paravirt_nop)
 186                 /* If the operation is a nop, then nop the callsite */
 187                 ret = paravirt_patch_nop();
 188         else if (type == PARAVIRT_PATCH(pv_cpu_ops.iret) ||
 189                  type == PARAVIRT_PATCH(pv_cpu_ops.irq_enable_syscall_ret))
 190                 /* If operation requires a jmp, then jmp */
 191                 ret = paravirt_patch_jmp(insnbuf, opfunc, addr, len);
 192         else
 193                 /* Otherwise call the function; assume target could
 194                    clobber any caller-save reg */
 195                 ret = paravirt_patch_call(insnbuf, opfunc, CLBR_ANY,
 196                                           addr, clobbers, len);
 197
 198         return ret;
 199 }
 200
 201 unsigned paravirt_patch_insns(void *insnbuf, unsigned len,
 202                               const char *start, const char *end)
 203 {
 204         unsigned insn_len = end - start;
 205
 206         if (insn_len > len || start == NULL)
 207                 insn_len = len;
 208         else
 209                 memcpy(insnbuf, start, insn_len);
 210
 211         return insn_len;
 212 }
 213
 214 void init_IRQ(void)
 215 {
 216         pv_irq_ops.init_IRQ();
 217 }
 218
 219 static void native_flush_tlb(void)
 220 {
 221         __native_flush_tlb();
 222 }
 223
 224 /*
 225  * Global pages have to be flushed a bit differently. Not a real
 226  * performance problem because this does not happen often.
 227  */
 228 static void native_flush_tlb_global(void)
 229 {
 230         __native_flush_tlb_global();
 231 }
 232
 233 static void native_flush_tlb_single(unsigned long addr)
 234 {
 235         __native_flush_tlb_single(addr);
 236 }
 237
 238 /* These are in entry.S */
 239 extern void native_iret(void);
 240 extern void native_irq_enable_syscall_ret(void);
 241
 242 static int __init print_banner(void)
 243 {
 244         pv_init_ops.banner();
 245         return 0;
 246 }
 247 core_initcall(print_banner);
 248
 249 static struct resource reserve_ioports = {
 250         .start = 0,
 251         .end = IO_SPACE_LIMIT,
 252         .name = "paravirt-ioport",
 253         .flags = IORESOURCE_IO | IORESOURCE_BUSY,
 254 };
 255
 256 static struct resource reserve_iomem = {
 257         .start = 0,
 258         .end = -1,
 259         .name = "paravirt-iomem",
 260         .flags = IORESOURCE_MEM | IORESOURCE_BUSY,
 261 };
 262
 263 /*
 264  * Reserve the whole legacy IO space to prevent any legacy drivers
 265  * from wasting time probing for their hardware.  This is a fairly
 266  * brute-force approach to disabling all non-virtual drivers.
 267  *
 268  * Note that this must be called very early to have any effect.
 269  */
 270 int paravirt_disable_iospace(void)
 271 {
 272         int ret;
 273
 274         ret = request_resource(&ioport_resource, &reserve_ioports);
 275         if (ret == 0) {
 276                 ret = request_resource(&iomem_resource, &reserve_iomem);
 277                 if (ret)
 278                         release_resource(&reserve_ioports);
 279         }
 280
 281         return ret;
 282 }
 283
 284 static DEFINE_PER_CPU(enum paravirt_lazy_mode, paravirt_lazy_mode) = PARAVIRT_LAZY_NONE;
 285
 286 static inline void enter_lazy(enum paravirt_lazy_mode mode)
 287 {
 288         BUG_ON(x86_read_percpu(paravirt_lazy_mode) != PARAVIRT_LAZY_NONE);
 289         BUG_ON(preemptible());
 290
 291         x86_write_percpu(paravirt_lazy_mode, mode);
 292 }
 293
 294 void paravirt_leave_lazy(enum paravirt_lazy_mode mode)
 295 {
 296         BUG_ON(x86_read_percpu(paravirt_lazy_mode) != mode);
 297         BUG_ON(preemptible());
 298
 299         x86_write_percpu(paravirt_lazy_mode, PARAVIRT_LAZY_NONE);
 300 }
 301
 302 void paravirt_enter_lazy_mmu(void)
 303 {
 304         enter_lazy(PARAVIRT_LAZY_MMU);
 305 }
 306
 307 void paravirt_leave_lazy_mmu(void)
 308 {
 309         paravirt_leave_lazy(PARAVIRT_LAZY_MMU);
 310 }
 311
 312 void paravirt_enter_lazy_cpu(void)
 313 {
 314         enter_lazy(PARAVIRT_LAZY_CPU);
 315 }
 316
 317 void paravirt_leave_lazy_cpu(void)
 318 {
 319         paravirt_leave_lazy(PARAVIRT_LAZY_CPU);
 320 }
 321
 322 enum paravirt_lazy_mode paravirt_get_lazy_mode(void)
 323 {
 324         return x86_read_percpu(paravirt_lazy_mode);
 325 }
 326
 327 struct pv_info pv_info = {
 328         .name = "bare hardware",
 329         .paravirt_enabled = 0,
 330         .kernel_rpl = 0,
 331         .shared_kernel_pmd = 1, /* Only used when CONFIG_X86_PAE is set */
 332 };
 333
 334 struct pv_init_ops pv_init_ops = {
 335         .patch = native_patch,
 336         .banner = default_banner,
 337         .arch_setup = paravirt_nop,
 338         .memory_setup = machine_specific_memory_setup,
 339 };
 340
 341 struct pv_time_ops pv_time_ops = {
 342         .time_init = hpet_time_init,
 343         .get_wallclock = native_get_wallclock,
 344         .set_wallclock = native_set_wallclock,
 345         .sched_clock = native_sched_clock,
 346         .get_cpu_khz = native_calculate_cpu_khz,
 347 };
 348
 349 struct pv_irq_ops pv_irq_ops = {
 350         .init_IRQ = native_init_IRQ,
 351         .save_fl = native_save_fl,
 352         .restore_fl = native_restore_fl,
 353         .irq_disable = native_irq_disable,
 354         .irq_enable = native_irq_enable,
 355         .safe_halt = native_safe_halt,
 356         .halt = native_halt,
 357 };
 358
 359 struct pv_cpu_ops pv_cpu_ops = {
 360         .cpuid = native_cpuid,
 361         .get_debugreg = native_get_debugreg,
 362         .set_debugreg = native_set_debugreg,
 363         .clts = native_clts,
 364         .read_cr0 = native_read_cr0,
 365         .write_cr0 = native_write_cr0,
 366         .read_cr4 = native_read_cr4,
 367         .read_cr4_safe = native_read_cr4_safe,
 368         .write_cr4 = native_write_cr4,
 369         .wbinvd = native_wbinvd,
 370         .read_msr = native_read_msr_safe,
 371         .write_msr = native_write_msr_safe,
 372         .read_tsc = native_read_tsc,
 373         .read_pmc = native_read_pmc,
 374         .load_tr_desc = native_load_tr_desc,
 375         .set_ldt = native_set_ldt,
 376         .load_gdt = native_load_gdt,
 377         .load_idt = native_load_idt,
 378         .store_gdt = native_store_gdt,
 379         .store_idt = native_store_idt,
 380         .store_tr = native_store_tr,
 381         .load_tls = native_load_tls,
 382         .write_ldt_entry = write_dt_entry,
 383         .write_gdt_entry = write_dt_entry,
 384         .write_idt_entry = write_dt_entry,
 385         .load_sp0 = native_load_sp0,
 386
 387         .irq_enable_syscall_ret = native_irq_enable_syscall_ret,
 388         .iret = native_iret,
 389
 390         .set_iopl_mask = native_set_iopl_mask,
 391         .io_delay = native_io_delay,
 392
 393         .lazy_mode = {
 394                 .enter = paravirt_nop,
 395                 .leave = paravirt_nop,
 396         },
 397 };
 398
 399 struct pv_apic_ops pv_apic_ops = {
 400 #ifdef CONFIG_X86_LOCAL_APIC
 401         .apic_write = native_apic_write,
 402         .apic_write_atomic = native_apic_write_atomic,
 403         .apic_read = native_apic_read,
 404         .setup_boot_clock = setup_boot_APIC_clock,
 405         .setup_secondary_clock = setup_secondary_APIC_clock,
 406         .startup_ipi_hook = paravirt_nop,
 407 #endif
 408 };
 409
 410 struct pv_mmu_ops pv_mmu_ops = {
 411         .pagetable_setup_start = native_pagetable_setup_start,
 412         .pagetable_setup_done = native_pagetable_setup_done,
 413
 414         .read_cr2 = native_read_cr2,
 415         .write_cr2 = native_write_cr2,
 416         .read_cr3 = native_read_cr3,
 417         .write_cr3 = native_write_cr3,
 418
 419         .flush_tlb_user = native_flush_tlb,
 420         .flush_tlb_kernel = native_flush_tlb_global,
 421         .flush_tlb_single = native_flush_tlb_single,
 422         .flush_tlb_others = native_flush_tlb_others,
 423
 424         .alloc_pt = paravirt_nop,
 425         .alloc_pd = paravirt_nop,
 426         .alloc_pd_clone = paravirt_nop,
 427         .release_pt = paravirt_nop,
 428         .release_pd = paravirt_nop,
 429
 430         .set_pte = native_set_pte,
 431         .set_pte_at = native_set_pte_at,
 432         .set_pmd = native_set_pmd,
 433         .pte_update = paravirt_nop,
 434         .pte_update_defer = paravirt_nop,
 435
 436 #ifdef CONFIG_HIGHPTE
 437         .kmap_atomic_pte = kmap_atomic,
 438 #endif
 439
 440 #ifdef CONFIG_X86_PAE
 441         .set_pte_atomic = native_set_pte_atomic,
 442         .set_pte_present = native_set_pte_present,
 443         .set_pud = native_set_pud,
 444         .pte_clear = native_pte_clear,
 445         .pmd_clear = native_pmd_clear,
 446
 447         .pmd_val = native_pmd_val,
 448         .make_pmd = native_make_pmd,
 449 #endif
 450
 451         .pte_val = native_pte_val,
 452         .pgd_val = native_pgd_val,
 453
 454         .make_pte = native_make_pte,
 455         .make_pgd = native_make_pgd,
 456
 457         .dup_mmap = paravirt_nop,
 458         .exit_mmap = paravirt_nop,
 459         .activate_mm = paravirt_nop,
 460
 461         .lazy_mode = {
 462                 .enter = paravirt_nop,
 463                 .leave = paravirt_nop,
 464         },
 465 };
 466
 467 EXPORT_SYMBOL_GPL(pv_time_ops);
 468 EXPORT_SYMBOL    (pv_cpu_ops);
 469 EXPORT_SYMBOL    (pv_mmu_ops);
 470 EXPORT_SYMBOL_GPL(pv_apic_ops);
 471 EXPORT_SYMBOL_GPL(pv_info);
 472 EXPORT_SYMBOL    (pv_irq_ops);