LXR linux/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 */
  43void _paravirt_nop(void)
  44{
  45}
  46
  47static void __init default_banner(void)
  48{
  49        printk(KERN_INFO "Booting paravirtualized kernel on %s\n",
  50               pv_info.name);
  51}
  52
  53char *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. */
  64static const unsigned char ud2a[] = { 0x0f, 0x0b };
  65
  66unsigned paravirt_patch_nop(void)
  67{
  68        return 0;
  69}
  70
  71unsigned paravirt_patch_ignore(unsigned len)
  72{
  73        return len;
  74}
  75
  76struct branch {
  77        unsigned char opcode;
  78        u32 delta;
  79} __attribute__((packed));
  80
  81unsigned 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
 101unsigned 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. */
 118static 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                .pv_lock_ops = pv_lock_ops,
 128        };
 129        return *((void **)&tmpl + type);
 130}
 131
 132unsigned paravirt_patch_default(u8 type, u16 clobbers, void *insnbuf,
 133                                unsigned long addr, unsigned len)
 134{
 135        void *opfunc = get_call_destination(type);
 136        unsigned ret;
 137
 138        if (opfunc == NULL)
 139                /* If there's no function, patch it with a ud2a (BUG) */
 140                ret = paravirt_patch_insns(insnbuf, len, ud2a, ud2a+sizeof(ud2a));
 141        else if (opfunc == paravirt_nop)
 142                /* If the operation is a nop, then nop the callsite */
 143                ret = paravirt_patch_nop();
 144        else if (type == PARAVIRT_PATCH(pv_cpu_ops.iret) ||
 145                 type == PARAVIRT_PATCH(pv_cpu_ops.irq_enable_sysexit) ||
 146                 type == PARAVIRT_PATCH(pv_cpu_ops.usergs_sysret32) ||
 147                 type == PARAVIRT_PATCH(pv_cpu_ops.usergs_sysret64))
 148                /* If operation requires a jmp, then jmp */
 149                ret = paravirt_patch_jmp(insnbuf, opfunc, addr, len);
 150        else
 151                /* Otherwise call the function; assume target could
 152                   clobber any caller-save reg */
 153                ret = paravirt_patch_call(insnbuf, opfunc, CLBR_ANY,
 154                                          addr, clobbers, len);
 155
 156        return ret;
 157}
 158
 159unsigned paravirt_patch_insns(void *insnbuf, unsigned len,
 160                              const char *start, const char *end)
 161{
 162        unsigned insn_len = end - start;
 163
 164        if (insn_len > len || start == NULL)
 165                insn_len = len;
 166        else
 167                memcpy(insnbuf, start, insn_len);
 168
 169        return insn_len;
 170}
 171
 172void init_IRQ(void)
 173{
 174        pv_irq_ops.init_IRQ();
 175}
 176
 177static void native_flush_tlb(void)
 178{
 179        __native_flush_tlb();
 180}
 181
 182/*
 183 * Global pages have to be flushed a bit differently. Not a real
 184 * performance problem because this does not happen often.
 185 */
 186static void native_flush_tlb_global(void)
 187{
 188        __native_flush_tlb_global();
 189}
 190
 191static void native_flush_tlb_single(unsigned long addr)
 192{
 193        __native_flush_tlb_single(addr);
 194}
 195
 196/* These are in entry.S */
 197extern void native_iret(void);
 198extern void native_irq_enable_sysexit(void);
 199extern void native_usergs_sysret32(void);
 200extern void native_usergs_sysret64(void);
 201
 202static int __init print_banner(void)
 203{
 204        pv_init_ops.banner();
 205        return 0;
 206}
 207core_initcall(print_banner);
 208
 209static struct resource reserve_ioports = {
 210        .start = 0,
 211        .end = IO_SPACE_LIMIT,
 212        .name = "paravirt-ioport",
 213        .flags = IORESOURCE_IO | 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 */
 223int paravirt_disable_iospace(void)
 224{
 225        return request_resource(&ioport_resource, &reserve_ioports);
 226}
 227
 228static DEFINE_PER_CPU(enum paravirt_lazy_mode, paravirt_lazy_mode) = PARAVIRT_LAZY_NONE;
 229
 230static inline void enter_lazy(enum paravirt_lazy_mode mode)
 231{
 232        BUG_ON(__get_cpu_var(paravirt_lazy_mode) != PARAVIRT_LAZY_NONE);
 233        BUG_ON(preemptible());
 234
 235        __get_cpu_var(paravirt_lazy_mode) = mode;
 236}
 237
 238void paravirt_leave_lazy(enum paravirt_lazy_mode mode)
 239{
 240        BUG_ON(__get_cpu_var(paravirt_lazy_mode) != mode);
 241        BUG_ON(preemptible());
 242
 243        __get_cpu_var(paravirt_lazy_mode) = PARAVIRT_LAZY_NONE;
 244}
 245
 246void paravirt_enter_lazy_mmu(void)
 247{
 248        enter_lazy(PARAVIRT_LAZY_MMU);
 249}
 250
 251void paravirt_leave_lazy_mmu(void)
 252{
 253        paravirt_leave_lazy(PARAVIRT_LAZY_MMU);
 254}
 255
 256void paravirt_enter_lazy_cpu(void)
 257{
 258        enter_lazy(PARAVIRT_LAZY_CPU);
 259}
 260
 261void paravirt_leave_lazy_cpu(void)
 262{
 263        paravirt_leave_lazy(PARAVIRT_LAZY_CPU);
 264}
 265
 266enum paravirt_lazy_mode paravirt_get_lazy_mode(void)
 267{
 268        return __get_cpu_var(paravirt_lazy_mode);
 269}
 270
 271struct pv_info pv_info = {
 272        .name = "bare hardware",
 273        .paravirt_enabled = 0,
 274        .kernel_rpl = 0,
 275        .shared_kernel_pmd = 1, /* Only used when CONFIG_X86_PAE is set */
 276};
 277
 278struct pv_init_ops pv_init_ops = {
 279        .patch = native_patch,
 280        .banner = default_banner,
 281        .arch_setup = paravirt_nop,
 282        .memory_setup = machine_specific_memory_setup,
 283};
 284
 285struct pv_time_ops pv_time_ops = {
 286        .time_init = hpet_time_init,
 287        .get_wallclock = native_get_wallclock,
 288        .set_wallclock = native_set_wallclock,
 289        .sched_clock = native_sched_clock,
 290        .get_tsc_khz = native_calibrate_tsc,
 291};
 292
 293struct pv_irq_ops pv_irq_ops = {
 294        .init_IRQ = native_init_IRQ,
 295        .save_fl = native_save_fl,
 296        .restore_fl = native_restore_fl,
 297        .irq_disable = native_irq_disable,
 298        .irq_enable = native_irq_enable,
 299        .safe_halt = native_safe_halt,
 300        .halt = native_halt,
 301#ifdef CONFIG_X86_64
 302        .adjust_exception_frame = paravirt_nop,
 303#endif
 304};
 305
 306struct pv_cpu_ops pv_cpu_ops = {
 307        .cpuid = native_cpuid,
 308        .get_debugreg = native_get_debugreg,
 309        .set_debugreg = native_set_debugreg,
 310        .clts = native_clts,
 311        .read_cr0 = native_read_cr0,
 312        .write_cr0 = native_write_cr0,
 313        .read_cr4 = native_read_cr4,
 314        .read_cr4_safe = native_read_cr4_safe,
 315        .write_cr4 = native_write_cr4,
 316#ifdef CONFIG_X86_64
 317        .read_cr8 = native_read_cr8,
 318        .write_cr8 = native_write_cr8,
 319#endif
 320        .wbinvd = native_wbinvd,
 321        .read_msr = native_read_msr_safe,
 322        .read_msr_amd = native_read_msr_amd_safe,
 323        .write_msr = native_write_msr_safe,
 324        .read_tsc = native_read_tsc,
 325        .read_pmc = native_read_pmc,
 326        .read_tscp = native_read_tscp,
 327        .load_tr_desc = native_load_tr_desc,
 328        .set_ldt = native_set_ldt,
 329        .load_gdt = native_load_gdt,
 330        .load_idt = native_load_idt,
 331        .store_gdt = native_store_gdt,
 332        .store_idt = native_store_idt,
 333        .store_tr = native_store_tr,
 334        .load_tls = native_load_tls,
 335#ifdef CONFIG_X86_64
 336        .load_gs_index = native_load_gs_index,
 337#endif
 338        .write_ldt_entry = native_write_ldt_entry,
 339        .write_gdt_entry = native_write_gdt_entry,
 340        .write_idt_entry = native_write_idt_entry,
 341
 342        .alloc_ldt = paravirt_nop,
 343        .free_ldt = paravirt_nop,
 344
 345        .load_sp0 = native_load_sp0,
 346
 347#if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)
 348        .irq_enable_sysexit = native_irq_enable_sysexit,
 349#endif
 350#ifdef CONFIG_X86_64
 351#ifdef CONFIG_IA32_EMULATION
 352        .usergs_sysret32 = native_usergs_sysret32,
 353#endif
 354        .usergs_sysret64 = native_usergs_sysret64,
 355#endif
 356        .iret = native_iret,
 357        .swapgs = native_swapgs,
 358
 359        .set_iopl_mask = native_set_iopl_mask,
 360        .io_delay = native_io_delay,
 361
 362        .lazy_mode = {
 363                .enter = paravirt_nop,
 364                .leave = paravirt_nop,
 365        },
 366};
 367
 368struct pv_apic_ops pv_apic_ops = {
 369#ifdef CONFIG_X86_LOCAL_APIC
 370        .setup_boot_clock = setup_boot_APIC_clock,
 371        .setup_secondary_clock = setup_secondary_APIC_clock,
 372        .startup_ipi_hook = paravirt_nop,
 373#endif
 374};
 375
 376struct pv_mmu_ops pv_mmu_ops = {
 377#ifndef CONFIG_X86_64
 378        .pagetable_setup_start = native_pagetable_setup_start,
 379        .pagetable_setup_done = native_pagetable_setup_done,
 380#else
 381        .pagetable_setup_start = paravirt_nop,
 382        .pagetable_setup_done = paravirt_nop,
 383#endif
 384
 385        .read_cr2 = native_read_cr2,
 386        .write_cr2 = native_write_cr2,
 387        .read_cr3 = native_read_cr3,
 388        .write_cr3 = native_write_cr3,
 389
 390        .flush_tlb_user = native_flush_tlb,
 391        .flush_tlb_kernel = native_flush_tlb_global,
 392        .flush_tlb_single = native_flush_tlb_single,
 393        .flush_tlb_others = native_flush_tlb_others,
 394
 395        .pgd_alloc = __paravirt_pgd_alloc,
 396        .pgd_free = paravirt_nop,
 397
 398        .alloc_pte = paravirt_nop,
 399        .alloc_pmd = paravirt_nop,
 400        .alloc_pmd_clone = paravirt_nop,
 401        .alloc_pud = paravirt_nop,
 402        .release_pte = paravirt_nop,
 403        .release_pmd = paravirt_nop,
 404        .release_pud = paravirt_nop,
 405
 406        .set_pte = native_set_pte,
 407        .set_pte_at = native_set_pte_at,
 408        .set_pmd = native_set_pmd,
 409        .pte_update = paravirt_nop,
 410        .pte_update_defer = paravirt_nop,
 411
 412        .ptep_modify_prot_start = __ptep_modify_prot_start,
 413        .ptep_modify_prot_commit = __ptep_modify_prot_commit,
 414
 415#ifdef CONFIG_HIGHPTE
 416        .kmap_atomic_pte = kmap_atomic,
 417#endif
 418
 419#if PAGETABLE_LEVELS >= 3
 420#ifdef CONFIG_X86_PAE
 421        .set_pte_atomic = native_set_pte_atomic,
 422        .set_pte_present = native_set_pte_present,
 423        .pte_clear = native_pte_clear,
 424        .pmd_clear = native_pmd_clear,
 425#endif
 426        .set_pud = native_set_pud,
 427        .pmd_val = native_pmd_val,
 428        .make_pmd = native_make_pmd,
 429
 430#if PAGETABLE_LEVELS == 4
 431        .pud_val = native_pud_val,
 432        .make_pud = native_make_pud,
 433        .set_pgd = native_set_pgd,
 434#endif
 435#endif /* PAGETABLE_LEVELS >= 3 */
 436
 437        .pte_val = native_pte_val,
 438        .pte_flags = native_pte_flags,
 439        .pgd_val = native_pgd_val,
 440
 441        .make_pte = native_make_pte,
 442        .make_pgd = native_make_pgd,
 443
 444        .dup_mmap = paravirt_nop,
 445        .exit_mmap = paravirt_nop,
 446        .activate_mm = paravirt_nop,
 447
 448        .lazy_mode = {
 449                .enter = paravirt_nop,
 450                .leave = paravirt_nop,
 451        },
 452
 453        .set_fixmap = native_set_fixmap,
 454};
 455
 456EXPORT_SYMBOL_GPL(pv_time_ops);
 457EXPORT_SYMBOL    (pv_cpu_ops);
 458EXPORT_SYMBOL    (pv_mmu_ops);
 459EXPORT_SYMBOL_GPL(pv_apic_ops);
 460EXPORT_SYMBOL_GPL(pv_info);
 461EXPORT_SYMBOL    (pv_irq_ops);
 462