LXR linux/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 */
  38void _paravirt_nop(void)
  39{
  40}
  41
  42static void __init default_banner(void)
  43{
  44        printk(KERN_INFO "Booting paravirtualized kernel on %s\n",
  45               paravirt_ops.name);
  46}
  47
  48char *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
  58DEF_NATIVE(irq_disable, "cli");
  59DEF_NATIVE(irq_enable, "sti");
  60DEF_NATIVE(restore_fl, "push %eax; popf");
  61DEF_NATIVE(save_fl, "pushf; pop %eax");
  62DEF_NATIVE(iret, "iret");
  63DEF_NATIVE(irq_enable_sysexit, "sti; sysexit");
  64DEF_NATIVE(read_cr2, "mov %cr2, %eax");
  65DEF_NATIVE(write_cr3, "mov %eax, %cr3");
  66DEF_NATIVE(read_cr3, "mov %cr3, %eax");
  67DEF_NATIVE(clts, "clts");
  68DEF_NATIVE(read_tsc, "rdtsc");
  69
  70DEF_NATIVE(ud2a, "ud2a");
  71
  72static 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
 117unsigned paravirt_patch_nop(void)
 118{
 119        return 0;
 120}
 121
 122unsigned paravirt_patch_ignore(unsigned len)
 123{
 124        return len;
 125}
 126
 127unsigned paravirt_patch_call(void *target, u16 tgt_clobbers,
 128                             void *site, u16 site_clobbers,
 129                             unsigned len)
 130{
 131        unsigned char *call = site;
 132        unsigned long delta = (unsigned long)target - (unsigned long)(call+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        *call++ = 0xe8;         /* call */
 140        *(unsigned long *)call = delta;
 141
 142        return 5;
 143}
 144
 145unsigned paravirt_patch_jmp(void *target, void *site, unsigned len)
 146{
 147        unsigned char *jmp = site;
 148        unsigned long delta = (unsigned long)target - (unsigned long)(jmp+5);
 149
 150        if (len < 5)
 151                return len;     /* call too long for patch site */
 152
 153        *jmp++ = 0xe9;          /* jmp */
 154        *(unsigned long *)jmp = delta;
 155
 156        return 5;
 157}
 158
 159unsigned paravirt_patch_default(u8 type, u16 clobbers, void *site, unsigned len)
 160{
 161        void *opfunc = *((void **)&paravirt_ops + type);
 162        unsigned ret;
 163
 164        if (opfunc == NULL)
 165                /* If there's no function, patch it with a ud2a (BUG) */
 166                ret = paravirt_patch_insns(site, len, start_ud2a, end_ud2a);
 167        else if (opfunc == paravirt_nop)
 168                /* If the operation is a nop, then nop the callsite */
 169                ret = paravirt_patch_nop();
 170        else if (type == PARAVIRT_PATCH(iret) ||
 171                 type == PARAVIRT_PATCH(irq_enable_sysexit))
 172                /* If operation requires a jmp, then jmp */
 173                ret = paravirt_patch_jmp(opfunc, site, len);
 174        else
 175                /* Otherwise call the function; assume target could
 176                   clobber any caller-save reg */
 177                ret = paravirt_patch_call(opfunc, CLBR_ANY,
 178                                          site, clobbers, len);
 179
 180        return ret;
 181}
 182
 183unsigned paravirt_patch_insns(void *site, unsigned len,
 184                              const char *start, const char *end)
 185{
 186        unsigned insn_len = end - start;
 187
 188        if (insn_len > len || start == NULL)
 189                insn_len = len;
 190        else
 191                memcpy(site, start, insn_len);
 192
 193        return insn_len;
 194}
 195
 196void init_IRQ(void)
 197{
 198        paravirt_ops.init_IRQ();
 199}
 200
 201static void native_flush_tlb(void)
 202{
 203        __native_flush_tlb();
 204}
 205
 206/*
 207 * Global pages have to be flushed a bit differently. Not a real
 208 * performance problem because this does not happen often.
 209 */
 210static void native_flush_tlb_global(void)
 211{
 212        __native_flush_tlb_global();
 213}
 214
 215static void native_flush_tlb_single(unsigned long addr)
 216{
 217        __native_flush_tlb_single(addr);
 218}
 219
 220/* These are in entry.S */
 221extern void native_iret(void);
 222extern void native_irq_enable_sysexit(void);
 223
 224static int __init print_banner(void)
 225{
 226        paravirt_ops.banner();
 227        return 0;
 228}
 229core_initcall(print_banner);
 230
 231struct paravirt_ops paravirt_ops = {
 232        .name = "bare hardware",
 233        .paravirt_enabled = 0,
 234        .kernel_rpl = 0,
 235        .shared_kernel_pmd = 1, /* Only used when CONFIG_X86_PAE is set */
 236
 237        .patch = native_patch,
 238        .banner = default_banner,
 239        .arch_setup = paravirt_nop,
 240        .memory_setup = machine_specific_memory_setup,
 241        .get_wallclock = native_get_wallclock,
 242        .set_wallclock = native_set_wallclock,
 243        .time_init = hpet_time_init,
 244        .init_IRQ = native_init_IRQ,
 245
 246        .cpuid = native_cpuid,
 247        .get_debugreg = native_get_debugreg,
 248        .set_debugreg = native_set_debugreg,
 249        .clts = native_clts,
 250        .read_cr0 = native_read_cr0,
 251        .write_cr0 = native_write_cr0,
 252        .read_cr2 = native_read_cr2,
 253        .write_cr2 = native_write_cr2,
 254        .read_cr3 = native_read_cr3,
 255        .write_cr3 = native_write_cr3,
 256        .read_cr4 = native_read_cr4,
 257        .read_cr4_safe = native_read_cr4_safe,
 258        .write_cr4 = native_write_cr4,
 259        .save_fl = native_save_fl,
 260        .restore_fl = native_restore_fl,
 261        .irq_disable = native_irq_disable,
 262        .irq_enable = native_irq_enable,
 263        .safe_halt = native_safe_halt,
 264        .halt = native_halt,
 265        .wbinvd = native_wbinvd,
 266        .read_msr = native_read_msr_safe,
 267        .write_msr = native_write_msr_safe,
 268        .read_tsc = native_read_tsc,
 269        .read_pmc = native_read_pmc,
 270        .get_scheduled_cycles = native_read_tsc,
 271        .get_cpu_khz = native_calculate_cpu_khz,
 272        .load_tr_desc = native_load_tr_desc,
 273        .set_ldt = native_set_ldt,
 274        .load_gdt = native_load_gdt,
 275        .load_idt = native_load_idt,
 276        .store_gdt = native_store_gdt,
 277        .store_idt = native_store_idt,
 278        .store_tr = native_store_tr,
 279        .load_tls = native_load_tls,
 280        .write_ldt_entry = write_dt_entry,
 281        .write_gdt_entry = write_dt_entry,
 282        .write_idt_entry = write_dt_entry,
 283        .load_esp0 = native_load_esp0,
 284
 285        .set_iopl_mask = native_set_iopl_mask,
 286        .io_delay = native_io_delay,
 287
 288#ifdef CONFIG_X86_LOCAL_APIC
 289        .apic_write = native_apic_write,
 290        .apic_write_atomic = native_apic_write_atomic,
 291        .apic_read = native_apic_read,
 292        .setup_boot_clock = setup_boot_APIC_clock,
 293        .setup_secondary_clock = setup_secondary_APIC_clock,
 294        .startup_ipi_hook = paravirt_nop,
 295#endif
 296        .set_lazy_mode = paravirt_nop,
 297
 298        .pagetable_setup_start = native_pagetable_setup_start,
 299        .pagetable_setup_done = native_pagetable_setup_done,
 300
 301        .flush_tlb_user = native_flush_tlb,
 302        .flush_tlb_kernel = native_flush_tlb_global,
 303        .flush_tlb_single = native_flush_tlb_single,
 304        .flush_tlb_others = native_flush_tlb_others,
 305
 306        .alloc_pt = paravirt_nop,
 307        .alloc_pd = paravirt_nop,
 308        .alloc_pd_clone = paravirt_nop,
 309        .release_pt = paravirt_nop,
 310        .release_pd = paravirt_nop,
 311
 312        .set_pte = native_set_pte,
 313        .set_pte_at = native_set_pte_at,
 314        .set_pmd = native_set_pmd,
 315        .pte_update = paravirt_nop,
 316        .pte_update_defer = paravirt_nop,
 317
 318#ifdef CONFIG_HIGHPTE
 319        .kmap_atomic_pte = kmap_atomic,
 320#endif
 321
 322#ifdef CONFIG_X86_PAE
 323        .set_pte_atomic = native_set_pte_atomic,
 324        .set_pte_present = native_set_pte_present,
 325        .set_pud = native_set_pud,
 326        .pte_clear = native_pte_clear,
 327        .pmd_clear = native_pmd_clear,
 328
 329        .pmd_val = native_pmd_val,
 330        .make_pmd = native_make_pmd,
 331#endif
 332
 333        .pte_val = native_pte_val,
 334        .pgd_val = native_pgd_val,
 335
 336        .make_pte = native_make_pte,
 337        .make_pgd = native_make_pgd,
 338
 339        .irq_enable_sysexit = native_irq_enable_sysexit,
 340        .iret = native_iret,
 341
 342        .dup_mmap = paravirt_nop,
 343        .exit_mmap = paravirt_nop,
 344        .activate_mm = paravirt_nop,
 345};
 346
 347EXPORT_SYMBOL(paravirt_ops);
 348