paravirt.c revision 78f28b7c555359c67c2a0d23f7436e915329421e
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/pgtable.h> 32#include <asm/time.h> 33#include <asm/pgalloc.h> 34#include <asm/irq.h> 35#include <asm/delay.h> 36#include <asm/fixmap.h> 37#include <asm/apic.h> 38#include <asm/tlbflush.h> 39#include <asm/timer.h> 40 41/* nop stub */ 42void _paravirt_nop(void) 43{ 44} 45 46/* identity function, which can be inlined */ 47u32 _paravirt_ident_32(u32 x) 48{ 49 return x; 50} 51 52u64 _paravirt_ident_64(u64 x) 53{ 54 return x; 55} 56 57void __init default_banner(void) 58{ 59 printk(KERN_INFO "Booting paravirtualized kernel on %s\n", 60 pv_info.name); 61} 62 63/* Simple instruction patching code. */ 64#define DEF_NATIVE(ops, name, code) \ 65 extern const char start_##ops##_##name[], end_##ops##_##name[]; \ 66 asm("start_" #ops "_" #name ": " code "; end_" #ops "_" #name ":") 67 68/* Undefined instruction for dealing with missing ops pointers. */ 69static const unsigned char ud2a[] = { 0x0f, 0x0b }; 70 71unsigned paravirt_patch_nop(void) 72{ 73 return 0; 74} 75 76unsigned paravirt_patch_ignore(unsigned len) 77{ 78 return len; 79} 80 81struct branch { 82 unsigned char opcode; 83 u32 delta; 84} __attribute__((packed)); 85 86unsigned paravirt_patch_call(void *insnbuf, 87 const void *target, u16 tgt_clobbers, 88 unsigned long addr, u16 site_clobbers, 89 unsigned len) 90{ 91 struct branch *b = insnbuf; 92 unsigned long delta = (unsigned long)target - (addr+5); 93 94 if (tgt_clobbers & ~site_clobbers) 95 return len; /* target would clobber too much for this site */ 96 if (len < 5) 97 return len; /* call too long for patch site */ 98 99 b->opcode = 0xe8; /* call */ 100 b->delta = delta; 101 BUILD_BUG_ON(sizeof(*b) != 5); 102 103 return 5; 104} 105 106unsigned paravirt_patch_jmp(void *insnbuf, const void *target, 107 unsigned long addr, unsigned len) 108{ 109 struct branch *b = insnbuf; 110 unsigned long delta = (unsigned long)target - (addr+5); 111 112 if (len < 5) 113 return len; /* call too long for patch site */ 114 115 b->opcode = 0xe9; /* jmp */ 116 b->delta = delta; 117 118 return 5; 119} 120 121/* Neat trick to map patch type back to the call within the 122 * corresponding structure. */ 123static void *get_call_destination(u8 type) 124{ 125 struct paravirt_patch_template tmpl = { 126 .pv_init_ops = pv_init_ops, 127 .pv_time_ops = pv_time_ops, 128 .pv_cpu_ops = pv_cpu_ops, 129 .pv_irq_ops = pv_irq_ops, 130 .pv_apic_ops = pv_apic_ops, 131 .pv_mmu_ops = pv_mmu_ops, 132#ifdef CONFIG_PARAVIRT_SPINLOCKS 133 .pv_lock_ops = pv_lock_ops, 134#endif 135 }; 136 return *((void **)&tmpl + type); 137} 138 139unsigned paravirt_patch_default(u8 type, u16 clobbers, void *insnbuf, 140 unsigned long addr, unsigned len) 141{ 142 void *opfunc = get_call_destination(type); 143 unsigned ret; 144 145 if (opfunc == NULL) 146 /* If there's no function, patch it with a ud2a (BUG) */ 147 ret = paravirt_patch_insns(insnbuf, len, ud2a, ud2a+sizeof(ud2a)); 148 else if (opfunc == _paravirt_nop) 149 /* If the operation is a nop, then nop the callsite */ 150 ret = paravirt_patch_nop(); 151 152 /* identity functions just return their single argument */ 153 else if (opfunc == _paravirt_ident_32) 154 ret = paravirt_patch_ident_32(insnbuf, len); 155 else if (opfunc == _paravirt_ident_64) 156 ret = paravirt_patch_ident_64(insnbuf, len); 157 158 else if (type == PARAVIRT_PATCH(pv_cpu_ops.iret) || 159 type == PARAVIRT_PATCH(pv_cpu_ops.irq_enable_sysexit) || 160 type == PARAVIRT_PATCH(pv_cpu_ops.usergs_sysret32) || 161 type == PARAVIRT_PATCH(pv_cpu_ops.usergs_sysret64)) 162 /* If operation requires a jmp, then jmp */ 163 ret = paravirt_patch_jmp(insnbuf, opfunc, addr, len); 164 else 165 /* Otherwise call the function; assume target could 166 clobber any caller-save reg */ 167 ret = paravirt_patch_call(insnbuf, opfunc, CLBR_ANY, 168 addr, clobbers, len); 169 170 return ret; 171} 172 173unsigned paravirt_patch_insns(void *insnbuf, unsigned len, 174 const char *start, const char *end) 175{ 176 unsigned insn_len = end - start; 177 178 if (insn_len > len || start == NULL) 179 insn_len = len; 180 else 181 memcpy(insnbuf, start, insn_len); 182 183 return insn_len; 184} 185 186static void native_flush_tlb(void) 187{ 188 __native_flush_tlb(); 189} 190 191/* 192 * Global pages have to be flushed a bit differently. Not a real 193 * performance problem because this does not happen often. 194 */ 195static void native_flush_tlb_global(void) 196{ 197 __native_flush_tlb_global(); 198} 199 200static void native_flush_tlb_single(unsigned long addr) 201{ 202 __native_flush_tlb_single(addr); 203} 204 205/* These are in entry.S */ 206extern void native_iret(void); 207extern void native_irq_enable_sysexit(void); 208extern void native_usergs_sysret32(void); 209extern void native_usergs_sysret64(void); 210 211static struct resource reserve_ioports = { 212 .start = 0, 213 .end = IO_SPACE_LIMIT, 214 .name = "paravirt-ioport", 215 .flags = IORESOURCE_IO | IORESOURCE_BUSY, 216}; 217 218/* 219 * Reserve the whole legacy IO space to prevent any legacy drivers 220 * from wasting time probing for their hardware. This is a fairly 221 * brute-force approach to disabling all non-virtual drivers. 222 * 223 * Note that this must be called very early to have any effect. 224 */ 225int paravirt_disable_iospace(void) 226{ 227 return request_resource(&ioport_resource, &reserve_ioports); 228} 229 230static DEFINE_PER_CPU(enum paravirt_lazy_mode, paravirt_lazy_mode) = PARAVIRT_LAZY_NONE; 231 232static inline void enter_lazy(enum paravirt_lazy_mode mode) 233{ 234 BUG_ON(percpu_read(paravirt_lazy_mode) != PARAVIRT_LAZY_NONE); 235 236 percpu_write(paravirt_lazy_mode, mode); 237} 238 239static void leave_lazy(enum paravirt_lazy_mode mode) 240{ 241 BUG_ON(percpu_read(paravirt_lazy_mode) != mode); 242 243 percpu_write(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 leave_lazy(PARAVIRT_LAZY_MMU); 254} 255 256void paravirt_start_context_switch(struct task_struct *prev) 257{ 258 BUG_ON(preemptible()); 259 260 if (percpu_read(paravirt_lazy_mode) == PARAVIRT_LAZY_MMU) { 261 arch_leave_lazy_mmu_mode(); 262 set_ti_thread_flag(task_thread_info(prev), TIF_LAZY_MMU_UPDATES); 263 } 264 enter_lazy(PARAVIRT_LAZY_CPU); 265} 266 267void paravirt_end_context_switch(struct task_struct *next) 268{ 269 BUG_ON(preemptible()); 270 271 leave_lazy(PARAVIRT_LAZY_CPU); 272 273 if (test_and_clear_ti_thread_flag(task_thread_info(next), TIF_LAZY_MMU_UPDATES)) 274 arch_enter_lazy_mmu_mode(); 275} 276 277enum paravirt_lazy_mode paravirt_get_lazy_mode(void) 278{ 279 if (in_interrupt()) 280 return PARAVIRT_LAZY_NONE; 281 282 return percpu_read(paravirt_lazy_mode); 283} 284 285void arch_flush_lazy_mmu_mode(void) 286{ 287 preempt_disable(); 288 289 if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) { 290 arch_leave_lazy_mmu_mode(); 291 arch_enter_lazy_mmu_mode(); 292 } 293 294 preempt_enable(); 295} 296 297struct pv_info pv_info = { 298 .name = "bare hardware", 299 .paravirt_enabled = 0, 300 .kernel_rpl = 0, 301 .shared_kernel_pmd = 1, /* Only used when CONFIG_X86_PAE is set */ 302}; 303 304struct pv_init_ops pv_init_ops = { 305 .patch = native_patch, 306}; 307 308struct pv_time_ops pv_time_ops = { 309 .sched_clock = native_sched_clock, 310}; 311 312struct pv_irq_ops pv_irq_ops = { 313 .save_fl = __PV_IS_CALLEE_SAVE(native_save_fl), 314 .restore_fl = __PV_IS_CALLEE_SAVE(native_restore_fl), 315 .irq_disable = __PV_IS_CALLEE_SAVE(native_irq_disable), 316 .irq_enable = __PV_IS_CALLEE_SAVE(native_irq_enable), 317 .safe_halt = native_safe_halt, 318 .halt = native_halt, 319#ifdef CONFIG_X86_64 320 .adjust_exception_frame = paravirt_nop, 321#endif 322}; 323 324struct pv_cpu_ops pv_cpu_ops = { 325 .cpuid = native_cpuid, 326 .get_debugreg = native_get_debugreg, 327 .set_debugreg = native_set_debugreg, 328 .clts = native_clts, 329 .read_cr0 = native_read_cr0, 330 .write_cr0 = native_write_cr0, 331 .read_cr4 = native_read_cr4, 332 .read_cr4_safe = native_read_cr4_safe, 333 .write_cr4 = native_write_cr4, 334#ifdef CONFIG_X86_64 335 .read_cr8 = native_read_cr8, 336 .write_cr8 = native_write_cr8, 337#endif 338 .wbinvd = native_wbinvd, 339 .read_msr = native_read_msr_safe, 340 .rdmsr_regs = native_rdmsr_safe_regs, 341 .write_msr = native_write_msr_safe, 342 .wrmsr_regs = native_wrmsr_safe_regs, 343 .read_tsc = native_read_tsc, 344 .read_pmc = native_read_pmc, 345 .read_tscp = native_read_tscp, 346 .load_tr_desc = native_load_tr_desc, 347 .set_ldt = native_set_ldt, 348 .load_gdt = native_load_gdt, 349 .load_idt = native_load_idt, 350 .store_gdt = native_store_gdt, 351 .store_idt = native_store_idt, 352 .store_tr = native_store_tr, 353 .load_tls = native_load_tls, 354#ifdef CONFIG_X86_64 355 .load_gs_index = native_load_gs_index, 356#endif 357 .write_ldt_entry = native_write_ldt_entry, 358 .write_gdt_entry = native_write_gdt_entry, 359 .write_idt_entry = native_write_idt_entry, 360 361 .alloc_ldt = paravirt_nop, 362 .free_ldt = paravirt_nop, 363 364 .load_sp0 = native_load_sp0, 365 366#if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION) 367 .irq_enable_sysexit = native_irq_enable_sysexit, 368#endif 369#ifdef CONFIG_X86_64 370#ifdef CONFIG_IA32_EMULATION 371 .usergs_sysret32 = native_usergs_sysret32, 372#endif 373 .usergs_sysret64 = native_usergs_sysret64, 374#endif 375 .iret = native_iret, 376 .swapgs = native_swapgs, 377 378 .set_iopl_mask = native_set_iopl_mask, 379 .io_delay = native_io_delay, 380 381 .start_context_switch = paravirt_nop, 382 .end_context_switch = paravirt_nop, 383}; 384 385struct pv_apic_ops pv_apic_ops = { 386#ifdef CONFIG_X86_LOCAL_APIC 387 .startup_ipi_hook = paravirt_nop, 388#endif 389}; 390 391#if defined(CONFIG_X86_32) && !defined(CONFIG_X86_PAE) 392/* 32-bit pagetable entries */ 393#define PTE_IDENT __PV_IS_CALLEE_SAVE(_paravirt_ident_32) 394#else 395/* 64-bit pagetable entries */ 396#define PTE_IDENT __PV_IS_CALLEE_SAVE(_paravirt_ident_64) 397#endif 398 399struct pv_mmu_ops pv_mmu_ops = { 400 401 .read_cr2 = native_read_cr2, 402 .write_cr2 = native_write_cr2, 403 .read_cr3 = native_read_cr3, 404 .write_cr3 = native_write_cr3, 405 406 .flush_tlb_user = native_flush_tlb, 407 .flush_tlb_kernel = native_flush_tlb_global, 408 .flush_tlb_single = native_flush_tlb_single, 409 .flush_tlb_others = native_flush_tlb_others, 410 411 .pgd_alloc = __paravirt_pgd_alloc, 412 .pgd_free = paravirt_nop, 413 414 .alloc_pte = paravirt_nop, 415 .alloc_pmd = paravirt_nop, 416 .alloc_pmd_clone = paravirt_nop, 417 .alloc_pud = paravirt_nop, 418 .release_pte = paravirt_nop, 419 .release_pmd = paravirt_nop, 420 .release_pud = paravirt_nop, 421 422 .set_pte = native_set_pte, 423 .set_pte_at = native_set_pte_at, 424 .set_pmd = native_set_pmd, 425 .pte_update = paravirt_nop, 426 .pte_update_defer = paravirt_nop, 427 428 .ptep_modify_prot_start = __ptep_modify_prot_start, 429 .ptep_modify_prot_commit = __ptep_modify_prot_commit, 430 431#ifdef CONFIG_HIGHPTE 432 .kmap_atomic_pte = kmap_atomic, 433#endif 434 435#if PAGETABLE_LEVELS >= 3 436#ifdef CONFIG_X86_PAE 437 .set_pte_atomic = native_set_pte_atomic, 438 .pte_clear = native_pte_clear, 439 .pmd_clear = native_pmd_clear, 440#endif 441 .set_pud = native_set_pud, 442 443 .pmd_val = PTE_IDENT, 444 .make_pmd = PTE_IDENT, 445 446#if PAGETABLE_LEVELS == 4 447 .pud_val = PTE_IDENT, 448 .make_pud = PTE_IDENT, 449 450 .set_pgd = native_set_pgd, 451#endif 452#endif /* PAGETABLE_LEVELS >= 3 */ 453 454 .pte_val = PTE_IDENT, 455 .pgd_val = PTE_IDENT, 456 457 .make_pte = PTE_IDENT, 458 .make_pgd = PTE_IDENT, 459 460 .dup_mmap = paravirt_nop, 461 .exit_mmap = paravirt_nop, 462 .activate_mm = paravirt_nop, 463 464 .lazy_mode = { 465 .enter = paravirt_nop, 466 .leave = paravirt_nop, 467 }, 468 469 .set_fixmap = native_set_fixmap, 470}; 471 472EXPORT_SYMBOL_GPL(pv_time_ops); 473EXPORT_SYMBOL (pv_cpu_ops); 474EXPORT_SYMBOL (pv_mmu_ops); 475EXPORT_SYMBOL_GPL(pv_apic_ops); 476EXPORT_SYMBOL_GPL(pv_info); 477EXPORT_SYMBOL (pv_irq_ops); 478