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