arch/i386/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 #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                paravirt_ops.name);
  46 }
  47
  48 char *memory_setup(void)
  49 {
  50         return paravirt_ops.memory_setup();
  51 }
  52
  53 /* Simple instruction patching code. */
  54 #define DEF_NATIVE(name, code)                                  \
  55         extern const char start_##name[], end_##name[];         \
  56         asm("start_" #name ": " code "; end_" #name ":")
  57
  58 DEF_NATIVE(irq_disable, "cli");
  59 DEF_NATIVE(irq_enable, "sti");
  60 DEF_NATIVE(restore_fl, "push %eax; popf");
  61 DEF_NATIVE(save_fl, "pushf; pop %eax");
  62 DEF_NATIVE(iret, "iret");
  63 DEF_NATIVE(irq_enable_sysexit, "sti; sysexit");
  64 DEF_NATIVE(read_cr2, "mov %cr2, %eax");
  65 DEF_NATIVE(write_cr3, "mov %eax, %cr3");
  66 DEF_NATIVE(read_cr3, "mov %cr3, %eax");
  67 DEF_NATIVE(clts, "clts");
  68 DEF_NATIVE(read_tsc, "rdtsc");
  69
  70 DEF_NATIVE(ud2a, "ud2a");
  71
  72 static unsigned native_patch(u8 type, u16 clobbers, void *insns, unsigned len)
  73 {
  74         const unsigned char *start, *end;
  75         unsigned ret;
  76
  77         switch(type) {
  78 #define SITE(x) case PARAVIRT_PATCH(x): start = start_##x; end = end_##x; goto patch_site
  79                 SITE(irq_disable);
  80                 SITE(irq_enable);
  81                 SITE(restore_fl);
  82                 SITE(save_fl);
  83                 SITE(iret);
  84                 SITE(irq_enable_sysexit);
  85                 SITE(read_cr2);
  86                 SITE(read_cr3);
  87                 SITE(write_cr3);
  88                 SITE(clts);
  89                 SITE(read_tsc);
  90 #undef SITE
  91
  92         patch_site:
  93                 ret = paravirt_patch_insns(insns, len, start, end);
  94                 break;
  95
  96         case PARAVIRT_PATCH(make_pgd):
  97         case PARAVIRT_PATCH(make_pte):
  98         case PARAVIRT_PATCH(pgd_val):
  99         case PARAVIRT_PATCH(pte_val):
 100 #ifdef CONFIG_X86_PAE
 101         case PARAVIRT_PATCH(make_pmd):
 102         case PARAVIRT_PATCH(pmd_val):
 103 #endif
 104                 /* These functions end up returning exactly what
 105                    they're passed, in the same registers. */
 106                 ret = paravirt_patch_nop();
 107                 break;
 108
 109         default:
 110                 ret = paravirt_patch_default(type, clobbers, insns, len);
 111                 break;
 112         }
 113
 114         return ret;
 115 }
 116
 117 unsigned paravirt_patch_nop(void)
 118 {
 119         return 0;
 120 }
 121
 122 unsigned paravirt_patch_ignore(unsigned len)
 123 {
 124         return len;
 125 }
 126
 127 struct branch {
 128         unsigned char opcode;
 129         u32 delta;
 130 } __attribute__((packed));
 131
 132 unsigned paravirt_patch_call(void *target, u16 tgt_clobbers,
 133                              void *site, u16 site_clobbers,
 134                              unsigned len)
 135 {
 136         unsigned char *call = site;
 137         unsigned long delta = (unsigned long)target - (unsigned long)(call+5);
 138         struct branch b;
 139
 140         if (tgt_clobbers & ~site_clobbers)
 141                 return len;     /* target would clobber too much for this site */
 142         if (len < 5)
 143                 return len;     /* call too long for patch site */
 144
 145         b.opcode = 0xe8; /* call */
 146         b.delta = delta;
 147         BUILD_BUG_ON(sizeof(b) != 5);
 148         text_poke(call, (unsigned char *)&b, 5);
 149
 150         return 5;
 151 }
 152
 153 unsigned paravirt_patch_jmp(void *target, void *site, unsigned len)
 154 {
 155         unsigned char *jmp = site;
 156         unsigned long delta = (unsigned long)target - (unsigned long)(jmp+5);
 157
 158         if (len < 5)
 159                 return len;     /* call too long for patch site */
 160
 161         b.opcode = 0xe9;        /* jmp */
 162         b.delta = delta;
 163         text_poke(call, (unsigned char *)&b, 5);
 164
 165         return 5;
 166 }
 167
 168 unsigned paravirt_patch_default(u8 type, u16 clobbers, void *site, unsigned len)
 169 {
 170         void *opfunc = *((void **)&paravirt_ops + type);
 171         unsigned ret;
 172
 173         if (opfunc == NULL)
 174                 /* If there's no function, patch it with a ud2a (BUG) */
 175                 ret = paravirt_patch_insns(site, len, start_ud2a, end_ud2a);
 176         else if (opfunc == paravirt_nop)
 177                 /* If the operation is a nop, then nop the callsite */
 178                 ret = paravirt_patch_nop();
 179         else if (type == PARAVIRT_PATCH(iret) ||
 180                  type == PARAVIRT_PATCH(irq_enable_sysexit))
 181                 /* If operation requires a jmp, then jmp */
 182                 ret = paravirt_patch_jmp(opfunc, site, len);
 183         else
 184                 /* Otherwise call the function; assume target could
 185                    clobber any caller-save reg */
 186                 ret = paravirt_patch_call(opfunc, CLBR_ANY,
 187                                           site, clobbers, len);
 188
 189         return ret;
 190 }
 191
 192 unsigned paravirt_patch_insns(void *site, unsigned len,
 193                               const char *start, const char *end)
 194 {
 195         unsigned insn_len = end - start;
 196
 197         if (insn_len > len || start == NULL)
 198                 insn_len = len;
 199         else
 200                 memcpy(site, start, insn_len);
 201
 202         return insn_len;
 203 }
 204
 205 void init_IRQ(void)
 206 {
 207         paravirt_ops.init_IRQ();
 208 }
 209
 210 static void native_flush_tlb(void)
 211 {
 212         __native_flush_tlb();
 213 }
 214
 215 /*
 216  * Global pages have to be flushed a bit differently. Not a real
 217  * performance problem because this does not happen often.
 218  */
 219 static void native_flush_tlb_global(void)
 220 {
 221         __native_flush_tlb_global();
 222 }
 223
 224 static void native_flush_tlb_single(unsigned long addr)
 225 {
 226         __native_flush_tlb_single(addr);
 227 }
 228
 229 /* These are in entry.S */
 230 extern void native_iret(void);
 231 extern void native_irq_enable_sysexit(void);
 232
 233 static int __init print_banner(void)
 234 {
 235         paravirt_ops.banner();
 236         return 0;
 237 }
 238 core_initcall(print_banner);
 239
 240 static struct resource reserve_ioports = {
 241         .start = 0,
 242         .end = IO_SPACE_LIMIT,
 243         .name = "paravirt-ioport",
 244         .flags = IORESOURCE_IO | IORESOURCE_BUSY,
 245 };
 246
 247 static struct resource reserve_iomem = {
 248         .start = 0,
 249         .end = -1,
 250         .name = "paravirt-iomem",
 251         .flags = IORESOURCE_MEM | IORESOURCE_BUSY,
 252 };
 253
 254 /*
 255  * Reserve the whole legacy IO space to prevent any legacy drivers
 256  * from wasting time probing for their hardware.  This is a fairly
 257  * brute-force approach to disabling all non-virtual drivers.
 258  *
 259  * Note that this must be called very early to have any effect.
 260  */
 261 int paravirt_disable_iospace(void)
 262 {
 263         int ret;
 264
 265         ret = request_resource(&ioport_resource, &reserve_ioports);
 266         if (ret == 0) {
 267                 ret = request_resource(&iomem_resource, &reserve_iomem);
 268                 if (ret)
 269                         release_resource(&reserve_ioports);
 270         }
 271
 272         return ret;
 273 }
 274
 275 struct paravirt_ops paravirt_ops = {
 276         .name = "bare hardware",
 277         .paravirt_enabled = 0,
 278         .kernel_rpl = 0,
 279         .shared_kernel_pmd = 1, /* Only used when CONFIG_X86_PAE is set */
 280
 281         .patch = native_patch,
 282         .banner = default_banner,
 283         .arch_setup = paravirt_nop,
 284         .memory_setup = machine_specific_memory_setup,
 285         .get_wallclock = native_get_wallclock,
 286         .set_wallclock = native_set_wallclock,
 287         .time_init = hpet_time_init,
 288         .init_IRQ = native_init_IRQ,
 289
 290         .cpuid = native_cpuid,
 291         .get_debugreg = native_get_debugreg,
 292         .set_debugreg = native_set_debugreg,
 293         .clts = native_clts,
 294         .read_cr0 = native_read_cr0,
 295         .write_cr0 = native_write_cr0,
 296         .read_cr2 = native_read_cr2,
 297         .write_cr2 = native_write_cr2,
 298         .read_cr3 = native_read_cr3,
 299         .write_cr3 = native_write_cr3,
 300         .read_cr4 = native_read_cr4,
 301         .read_cr4_safe = native_read_cr4_safe,
 302         .write_cr4 = native_write_cr4,
 303         .save_fl = native_save_fl,
 304         .restore_fl = native_restore_fl,
 305         .irq_disable = native_irq_disable,
 306         .irq_enable = native_irq_enable,
 307         .safe_halt = native_safe_halt,
 308         .halt = native_halt,
 309         .wbinvd = native_wbinvd,
 310         .read_msr = native_read_msr_safe,
 311         .write_msr = native_write_msr_safe,
 312         .read_tsc = native_read_tsc,
 313         .read_pmc = native_read_pmc,
 314         .sched_clock = native_sched_clock,
 315         .get_cpu_khz = native_calculate_cpu_khz,
 316         .load_tr_desc = native_load_tr_desc,
 317         .set_ldt = native_set_ldt,
 318         .load_gdt = native_load_gdt,
 319         .load_idt = native_load_idt,
 320         .store_gdt = native_store_gdt,
 321         .store_idt = native_store_idt,
 322         .store_tr = native_store_tr,
 323         .load_tls = native_load_tls,
 324         .write_ldt_entry = write_dt_entry,
 325         .write_gdt_entry = write_dt_entry,
 326         .write_idt_entry = write_dt_entry,
 327         .load_esp0 = native_load_esp0,
 328
 329         .set_iopl_mask = native_set_iopl_mask,
 330         .io_delay = native_io_delay,
 331
 332 #ifdef CONFIG_X86_LOCAL_APIC
 333         .apic_write = native_apic_write,
 334         .apic_write_atomic = native_apic_write_atomic,
 335         .apic_read = native_apic_read,
 336         .setup_boot_clock = setup_boot_APIC_clock,
 337         .setup_secondary_clock = setup_secondary_APIC_clock,
 338         .startup_ipi_hook = paravirt_nop,
 339 #endif
 340         .set_lazy_mode = paravirt_nop,
 341
 342         .pagetable_setup_start = native_pagetable_setup_start,
 343         .pagetable_setup_done = native_pagetable_setup_done,
 344
 345         .flush_tlb_user = native_flush_tlb,
 346         .flush_tlb_kernel = native_flush_tlb_global,
 347         .flush_tlb_single = native_flush_tlb_single,
 348         .flush_tlb_others = native_flush_tlb_others,
 349
 350         .alloc_pt = paravirt_nop,
 351         .alloc_pd = paravirt_nop,
 352         .alloc_pd_clone = paravirt_nop,
 353         .release_pt = paravirt_nop,
 354         .release_pd = paravirt_nop,
 355
 356         .set_pte = native_set_pte,
 357         .set_pte_at = native_set_pte_at,
 358         .set_pmd = native_set_pmd,
 359         .pte_update = paravirt_nop,
 360         .pte_update_defer = paravirt_nop,
 361
 362 #ifdef CONFIG_HIGHPTE
 363         .kmap_atomic_pte = kmap_atomic,
 364 #endif
 365
 366 #ifdef CONFIG_X86_PAE
 367         .set_pte_atomic = native_set_pte_atomic,
 368         .set_pte_present = native_set_pte_present,
 369         .set_pud = native_set_pud,
 370         .pte_clear = native_pte_clear,
 371         .pmd_clear = native_pmd_clear,
 372
 373         .pmd_val = native_pmd_val,
 374         .make_pmd = native_make_pmd,
 375 #endif
 376
 377         .pte_val = native_pte_val,
 378         .pgd_val = native_pgd_val,
 379
 380         .make_pte = native_make_pte,
 381         .make_pgd = native_make_pgd,
 382
 383         .irq_enable_sysexit = native_irq_enable_sysexit,
 384         .iret = native_iret,
 385
 386         .dup_mmap = paravirt_nop,
 387         .exit_mmap = paravirt_nop,
 388         .activate_mm = paravirt_nop,
 389 };
 390
 391 EXPORT_SYMBOL(paravirt_ops);