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