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