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