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 #include <linux/kprobes.h> 27 28 #include <asm/bug.h> 29 #include <asm/paravirt.h> 30 #include <asm/debugreg.h> 31 #include <asm/desc.h> 32 #include <asm/setup.h> 33 #include <asm/pgtable.h> 34 #include <asm/time.h> 35 #include <asm/pgalloc.h> 36 #include <asm/irq.h> 37 #include <asm/delay.h> 38 #include <asm/fixmap.h> 39 #include <asm/apic.h> 40 #include <asm/tlbflush.h> 41 #include <asm/timer.h> 42 #include <asm/special_insns.h> 43 44 /* 45 * nop stub, which must not clobber anything *including the stack* to 46 * avoid confusing the entry prologues. 47 */ 48 extern void _paravirt_nop(void); 49 asm (".pushsection .entry.text, \"ax\"\n" 50 ".global _paravirt_nop\n" 51 "_paravirt_nop:\n\t" 52 "ret\n\t" 53 ".size _paravirt_nop, . - _paravirt_nop\n\t" 54 ".type _paravirt_nop, @function\n\t" 55 ".popsection"); 56 57 /* identity function, which can be inlined */ 58 u32 _paravirt_ident_32(u32 x) 59 { 60 return x; 61 } 62 63 u64 _paravirt_ident_64(u64 x) 64 { 65 return x; 66 } 67 68 void __init default_banner(void) 69 { 70 printk(KERN_INFO "Booting paravirtualized kernel on %s\n", 71 pv_info.name); 72 } 73 74 /* Undefined instruction for dealing with missing ops pointers. */ 75 static const unsigned char ud2a[] = { 0x0f, 0x0b }; 76 77 unsigned paravirt_patch_nop(void) 78 { 79 return 0; 80 } 81 82 unsigned paravirt_patch_ignore(unsigned len) 83 { 84 return len; 85 } 86 87 struct branch { 88 unsigned char opcode; 89 u32 delta; 90 } __attribute__((packed)); 91 92 unsigned paravirt_patch_call(void *insnbuf, 93 const void *target, u16 tgt_clobbers, 94 unsigned long addr, u16 site_clobbers, 95 unsigned len) 96 { 97 struct branch *b = insnbuf; 98 unsigned long delta = (unsigned long)target - (addr+5); 99 100 if (tgt_clobbers & ~site_clobbers) 101 return len; /* target would clobber too much for this site */ 102 if (len < 5) 103 return len; /* call too long for patch site */ 104 105 b->opcode = 0xe8; /* call */ 106 b->delta = delta; 107 BUILD_BUG_ON(sizeof(*b) != 5); 108 109 return 5; 110 } 111 112 unsigned paravirt_patch_jmp(void *insnbuf, const void *target, 113 unsigned long addr, unsigned len) 114 { 115 struct branch *b = insnbuf; 116 unsigned long delta = (unsigned long)target - (addr+5); 117 118 if (len < 5) 119 return len; /* call too long for patch site */ 120 121 b->opcode = 0xe9; /* jmp */ 122 b->delta = delta; 123 124 return 5; 125 } 126 127 /* Neat trick to map patch type back to the call within the 128 * corresponding structure. */ 129 static void *get_call_destination(u8 type) 130 { 131 struct paravirt_patch_template tmpl = { 132 .pv_init_ops = pv_init_ops, 133 .pv_time_ops = pv_time_ops, 134 .pv_cpu_ops = pv_cpu_ops, 135 .pv_irq_ops = pv_irq_ops, 136 .pv_apic_ops = pv_apic_ops, 137 .pv_mmu_ops = pv_mmu_ops, 138 #ifdef CONFIG_PARAVIRT_SPINLOCKS 139 .pv_lock_ops = pv_lock_ops, 140 #endif 141 }; 142 return *((void **)&tmpl + type); 143 } 144 145 unsigned paravirt_patch_default(u8 type, u16 clobbers, void *insnbuf, 146 unsigned long addr, unsigned len) 147 { 148 void *opfunc = get_call_destination(type); 149 unsigned ret; 150 151 if (opfunc == NULL) 152 /* If there's no function, patch it with a ud2a (BUG) */ 153 ret = paravirt_patch_insns(insnbuf, len, ud2a, ud2a+sizeof(ud2a)); 154 else if (opfunc == _paravirt_nop) 155 /* If the operation is a nop, then nop the callsite */ 156 ret = paravirt_patch_nop(); 157 158 /* identity functions just return their single argument */ 159 else if (opfunc == _paravirt_ident_32) 160 ret = paravirt_patch_ident_32(insnbuf, len); 161 else if (opfunc == _paravirt_ident_64) 162 ret = paravirt_patch_ident_64(insnbuf, len); 163 164 else if (type == PARAVIRT_PATCH(pv_cpu_ops.iret) || 165 #ifdef CONFIG_X86_32 166 type == PARAVIRT_PATCH(pv_cpu_ops.irq_enable_sysexit) || 167 #endif 168 type == PARAVIRT_PATCH(pv_cpu_ops.usergs_sysret32) || 169 type == PARAVIRT_PATCH(pv_cpu_ops.usergs_sysret64)) 170 /* If operation requires a jmp, then jmp */ 171 ret = paravirt_patch_jmp(insnbuf, opfunc, addr, len); 172 else 173 /* Otherwise call the function; assume target could 174 clobber any caller-save reg */ 175 ret = paravirt_patch_call(insnbuf, opfunc, CLBR_ANY, 176 addr, clobbers, len); 177 178 return ret; 179 } 180 181 unsigned paravirt_patch_insns(void *insnbuf, unsigned len, 182 const char *start, const char *end) 183 { 184 unsigned insn_len = end - start; 185 186 if (insn_len > len || start == NULL) 187 insn_len = len; 188 else 189 memcpy(insnbuf, start, insn_len); 190 191 return insn_len; 192 } 193 194 static void native_flush_tlb(void) 195 { 196 __native_flush_tlb(); 197 } 198 199 /* 200 * Global pages have to be flushed a bit differently. Not a real 201 * performance problem because this does not happen often. 202 */ 203 static void native_flush_tlb_global(void) 204 { 205 __native_flush_tlb_global(); 206 } 207 208 static void native_flush_tlb_single(unsigned long addr) 209 { 210 __native_flush_tlb_single(addr); 211 } 212 213 struct static_key paravirt_steal_enabled; 214 struct static_key paravirt_steal_rq_enabled; 215 216 static u64 native_steal_clock(int cpu) 217 { 218 return 0; 219 } 220 221 /* These are in entry.S */ 222 extern void native_iret(void); 223 extern void native_irq_enable_sysexit(void); 224 extern void native_usergs_sysret32(void); 225 extern void native_usergs_sysret64(void); 226 227 static struct resource reserve_ioports = { 228 .start = 0, 229 .end = IO_SPACE_LIMIT, 230 .name = "paravirt-ioport", 231 .flags = IORESOURCE_IO | IORESOURCE_BUSY, 232 }; 233 234 /* 235 * Reserve the whole legacy IO space to prevent any legacy drivers 236 * from wasting time probing for their hardware. This is a fairly 237 * brute-force approach to disabling all non-virtual drivers. 238 * 239 * Note that this must be called very early to have any effect. 240 */ 241 int paravirt_disable_iospace(void) 242 { 243 return request_resource(&ioport_resource, &reserve_ioports); 244 } 245 246 static DEFINE_PER_CPU(enum paravirt_lazy_mode, paravirt_lazy_mode) = PARAVIRT_LAZY_NONE; 247 248 static inline void enter_lazy(enum paravirt_lazy_mode mode) 249 { 250 BUG_ON(this_cpu_read(paravirt_lazy_mode) != PARAVIRT_LAZY_NONE); 251 252 this_cpu_write(paravirt_lazy_mode, mode); 253 } 254 255 static void leave_lazy(enum paravirt_lazy_mode mode) 256 { 257 BUG_ON(this_cpu_read(paravirt_lazy_mode) != mode); 258 259 this_cpu_write(paravirt_lazy_mode, PARAVIRT_LAZY_NONE); 260 } 261 262 void paravirt_enter_lazy_mmu(void) 263 { 264 enter_lazy(PARAVIRT_LAZY_MMU); 265 } 266 267 void paravirt_leave_lazy_mmu(void) 268 { 269 leave_lazy(PARAVIRT_LAZY_MMU); 270 } 271 272 void paravirt_flush_lazy_mmu(void) 273 { 274 preempt_disable(); 275 276 if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) { 277 arch_leave_lazy_mmu_mode(); 278 arch_enter_lazy_mmu_mode(); 279 } 280 281 preempt_enable(); 282 } 283 284 void paravirt_start_context_switch(struct task_struct *prev) 285 { 286 BUG_ON(preemptible()); 287 288 if (this_cpu_read(paravirt_lazy_mode) == PARAVIRT_LAZY_MMU) { 289 arch_leave_lazy_mmu_mode(); 290 set_ti_thread_flag(task_thread_info(prev), TIF_LAZY_MMU_UPDATES); 291 } 292 enter_lazy(PARAVIRT_LAZY_CPU); 293 } 294 295 void paravirt_end_context_switch(struct task_struct *next) 296 { 297 BUG_ON(preemptible()); 298 299 leave_lazy(PARAVIRT_LAZY_CPU); 300 301 if (test_and_clear_ti_thread_flag(task_thread_info(next), TIF_LAZY_MMU_UPDATES)) 302 arch_enter_lazy_mmu_mode(); 303 } 304 305 enum paravirt_lazy_mode paravirt_get_lazy_mode(void) 306 { 307 if (in_interrupt()) 308 return PARAVIRT_LAZY_NONE; 309 310 return this_cpu_read(paravirt_lazy_mode); 311 } 312 313 struct pv_info pv_info = { 314 .name = "bare hardware", 315 .paravirt_enabled = 0, 316 .kernel_rpl = 0, 317 .shared_kernel_pmd = 1, /* Only used when CONFIG_X86_PAE is set */ 318 319 #ifdef CONFIG_X86_64 320 .extra_user_64bit_cs = __USER_CS, 321 #endif 322 }; 323 324 struct pv_init_ops pv_init_ops = { 325 .patch = native_patch, 326 }; 327 328 struct pv_time_ops pv_time_ops = { 329 .sched_clock = native_sched_clock, 330 .steal_clock = native_steal_clock, 331 }; 332 333 __visible struct pv_irq_ops pv_irq_ops = { 334 .save_fl = __PV_IS_CALLEE_SAVE(native_save_fl), 335 .restore_fl = __PV_IS_CALLEE_SAVE(native_restore_fl), 336 .irq_disable = __PV_IS_CALLEE_SAVE(native_irq_disable), 337 .irq_enable = __PV_IS_CALLEE_SAVE(native_irq_enable), 338 .safe_halt = native_safe_halt, 339 .halt = native_halt, 340 #ifdef CONFIG_X86_64 341 .adjust_exception_frame = paravirt_nop, 342 #endif 343 }; 344 345 __visible struct pv_cpu_ops pv_cpu_ops = { 346 .cpuid = native_cpuid, 347 .get_debugreg = native_get_debugreg, 348 .set_debugreg = native_set_debugreg, 349 .clts = native_clts, 350 .read_cr0 = native_read_cr0, 351 .write_cr0 = native_write_cr0, 352 .read_cr4 = native_read_cr4, 353 .read_cr4_safe = native_read_cr4_safe, 354 .write_cr4 = native_write_cr4, 355 #ifdef CONFIG_X86_64 356 .read_cr8 = native_read_cr8, 357 .write_cr8 = native_write_cr8, 358 #endif 359 .wbinvd = native_wbinvd, 360 .read_msr = native_read_msr_safe, 361 .write_msr = native_write_msr_safe, 362 .read_pmc = native_read_pmc, 363 .load_tr_desc = native_load_tr_desc, 364 .set_ldt = native_set_ldt, 365 .load_gdt = native_load_gdt, 366 .load_idt = native_load_idt, 367 .store_idt = native_store_idt, 368 .store_tr = native_store_tr, 369 .load_tls = native_load_tls, 370 #ifdef CONFIG_X86_64 371 .load_gs_index = native_load_gs_index, 372 #endif 373 .write_ldt_entry = native_write_ldt_entry, 374 .write_gdt_entry = native_write_gdt_entry, 375 .write_idt_entry = native_write_idt_entry, 376 377 .alloc_ldt = paravirt_nop, 378 .free_ldt = paravirt_nop, 379 380 .load_sp0 = native_load_sp0, 381 382 #if defined(CONFIG_X86_32) 383 .irq_enable_sysexit = native_irq_enable_sysexit, 384 #endif 385 #ifdef CONFIG_X86_64 386 #ifdef CONFIG_IA32_EMULATION 387 .usergs_sysret32 = native_usergs_sysret32, 388 #endif 389 .usergs_sysret64 = native_usergs_sysret64, 390 #endif 391 .iret = native_iret, 392 .swapgs = native_swapgs, 393 394 .set_iopl_mask = native_set_iopl_mask, 395 .io_delay = native_io_delay, 396 397 .start_context_switch = paravirt_nop, 398 .end_context_switch = paravirt_nop, 399 }; 400 401 /* At this point, native_get/set_debugreg has real function entries */ 402 NOKPROBE_SYMBOL(native_get_debugreg); 403 NOKPROBE_SYMBOL(native_set_debugreg); 404 NOKPROBE_SYMBOL(native_load_idt); 405 406 struct pv_apic_ops pv_apic_ops = { 407 #ifdef CONFIG_X86_LOCAL_APIC 408 .startup_ipi_hook = paravirt_nop, 409 #endif 410 }; 411 412 #if defined(CONFIG_X86_32) && !defined(CONFIG_X86_PAE) 413 /* 32-bit pagetable entries */ 414 #define PTE_IDENT __PV_IS_CALLEE_SAVE(_paravirt_ident_32) 415 #else 416 /* 64-bit pagetable entries */ 417 #define PTE_IDENT __PV_IS_CALLEE_SAVE(_paravirt_ident_64) 418 #endif 419 420 struct pv_mmu_ops pv_mmu_ops = { 421 422 .read_cr2 = native_read_cr2, 423 .write_cr2 = native_write_cr2, 424 .read_cr3 = native_read_cr3, 425 .write_cr3 = native_write_cr3, 426 427 .flush_tlb_user = native_flush_tlb, 428 .flush_tlb_kernel = native_flush_tlb_global, 429 .flush_tlb_single = native_flush_tlb_single, 430 .flush_tlb_others = native_flush_tlb_others, 431 432 .pgd_alloc = __paravirt_pgd_alloc, 433 .pgd_free = paravirt_nop, 434 435 .alloc_pte = paravirt_nop, 436 .alloc_pmd = paravirt_nop, 437 .alloc_pud = paravirt_nop, 438 .release_pte = paravirt_nop, 439 .release_pmd = paravirt_nop, 440 .release_pud = paravirt_nop, 441 442 .set_pte = native_set_pte, 443 .set_pte_at = native_set_pte_at, 444 .set_pmd = native_set_pmd, 445 .set_pmd_at = native_set_pmd_at, 446 .pte_update = paravirt_nop, 447 .pte_update_defer = paravirt_nop, 448 .pmd_update = paravirt_nop, 449 .pmd_update_defer = paravirt_nop, 450 451 .ptep_modify_prot_start = __ptep_modify_prot_start, 452 .ptep_modify_prot_commit = __ptep_modify_prot_commit, 453 454 #if CONFIG_PGTABLE_LEVELS >= 3 455 #ifdef CONFIG_X86_PAE 456 .set_pte_atomic = native_set_pte_atomic, 457 .pte_clear = native_pte_clear, 458 .pmd_clear = native_pmd_clear, 459 #endif 460 .set_pud = native_set_pud, 461 462 .pmd_val = PTE_IDENT, 463 .make_pmd = PTE_IDENT, 464 465 #if CONFIG_PGTABLE_LEVELS == 4 466 .pud_val = PTE_IDENT, 467 .make_pud = PTE_IDENT, 468 469 .set_pgd = native_set_pgd, 470 #endif 471 #endif /* CONFIG_PGTABLE_LEVELS >= 3 */ 472 473 .pte_val = PTE_IDENT, 474 .pgd_val = PTE_IDENT, 475 476 .make_pte = PTE_IDENT, 477 .make_pgd = PTE_IDENT, 478 479 .dup_mmap = paravirt_nop, 480 .exit_mmap = paravirt_nop, 481 .activate_mm = paravirt_nop, 482 483 .lazy_mode = { 484 .enter = paravirt_nop, 485 .leave = paravirt_nop, 486 .flush = paravirt_nop, 487 }, 488 489 .set_fixmap = native_set_fixmap, 490 }; 491 492 EXPORT_SYMBOL_GPL(pv_time_ops); 493 EXPORT_SYMBOL (pv_cpu_ops); 494 EXPORT_SYMBOL (pv_mmu_ops); 495 EXPORT_SYMBOL_GPL(pv_apic_ops); 496 EXPORT_SYMBOL_GPL(pv_info); 497 EXPORT_SYMBOL (pv_irq_ops); 498