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