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/init.h> 23 #include <linux/export.h> 24 #include <linux/efi.h> 25 #include <linux/bcd.h> 26 #include <linux/highmem.h> 27 #include <linux/kprobes.h> 28 29 #include <asm/bug.h> 30 #include <asm/paravirt.h> 31 #include <asm/debugreg.h> 32 #include <asm/desc.h> 33 #include <asm/setup.h> 34 #include <asm/pgtable.h> 35 #include <asm/time.h> 36 #include <asm/pgalloc.h> 37 #include <asm/irq.h> 38 #include <asm/delay.h> 39 #include <asm/fixmap.h> 40 #include <asm/apic.h> 41 #include <asm/tlbflush.h> 42 #include <asm/timer.h> 43 #include <asm/special_insns.h> 44 45 /* 46 * nop stub, which must not clobber anything *including the stack* to 47 * avoid confusing the entry prologues. 48 */ 49 extern void _paravirt_nop(void); 50 asm (".pushsection .entry.text, \"ax\"\n" 51 ".global _paravirt_nop\n" 52 "_paravirt_nop:\n\t" 53 "ret\n\t" 54 ".size _paravirt_nop, . - _paravirt_nop\n\t" 55 ".type _paravirt_nop, @function\n\t" 56 ".popsection"); 57 58 /* identity function, which can be inlined */ 59 u32 notrace _paravirt_ident_32(u32 x) 60 { 61 return x; 62 } 63 64 u64 notrace _paravirt_ident_64(u64 x) 65 { 66 return x; 67 } 68 69 void __init default_banner(void) 70 { 71 printk(KERN_INFO "Booting paravirtualized kernel on %s\n", 72 pv_info.name); 73 } 74 75 /* Undefined instruction for dealing with missing ops pointers. */ 76 static const unsigned char ud2a[] = { 0x0f, 0x0b }; 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 (len < 5) { 92 #ifdef CONFIG_RETPOLINE 93 WARN_ONCE("Failing to patch indirect CALL in %ps\n", (void *)addr); 94 #endif 95 return len; /* call too long for patch site */ 96 } 97 98 b->opcode = 0xe8; /* call */ 99 b->delta = delta; 100 BUILD_BUG_ON(sizeof(*b) != 5); 101 102 return 5; 103 } 104 105 unsigned paravirt_patch_jmp(void *insnbuf, const void *target, 106 unsigned long addr, unsigned len) 107 { 108 struct branch *b = insnbuf; 109 unsigned long delta = (unsigned long)target - (addr+5); 110 111 if (len < 5) { 112 #ifdef CONFIG_RETPOLINE 113 WARN_ONCE("Failing to patch indirect JMP in %ps\n", (void *)addr); 114 #endif 115 return len; /* call too long for patch site */ 116 } 117 118 b->opcode = 0xe9; /* jmp */ 119 b->delta = delta; 120 121 return 5; 122 } 123 124 DEFINE_STATIC_KEY_TRUE(virt_spin_lock_key); 125 126 void __init native_pv_lock_init(void) 127 { 128 if (!static_cpu_has(X86_FEATURE_HYPERVISOR)) 129 static_branch_disable(&virt_spin_lock_key); 130 } 131 132 /* 133 * Neat trick to map patch type back to the call within the 134 * corresponding structure. 135 */ 136 static void *get_call_destination(u8 type) 137 { 138 struct paravirt_patch_template tmpl = { 139 .pv_init_ops = pv_init_ops, 140 .pv_time_ops = pv_time_ops, 141 .pv_cpu_ops = pv_cpu_ops, 142 .pv_irq_ops = pv_irq_ops, 143 .pv_mmu_ops = pv_mmu_ops, 144 #ifdef CONFIG_PARAVIRT_SPINLOCKS 145 .pv_lock_ops = pv_lock_ops, 146 #endif 147 }; 148 return *((void **)&tmpl + type); 149 } 150 151 unsigned paravirt_patch_default(u8 type, u16 clobbers, void *insnbuf, 152 unsigned long addr, unsigned len) 153 { 154 void *opfunc = get_call_destination(type); 155 unsigned ret; 156 157 if (opfunc == NULL) 158 /* If there's no function, patch it with a ud2a (BUG) */ 159 ret = paravirt_patch_insns(insnbuf, len, ud2a, ud2a+sizeof(ud2a)); 160 else if (opfunc == _paravirt_nop) 161 ret = 0; 162 163 /* identity functions just return their single argument */ 164 else if (opfunc == _paravirt_ident_32) 165 ret = paravirt_patch_ident_32(insnbuf, len); 166 else if (opfunc == _paravirt_ident_64) 167 ret = paravirt_patch_ident_64(insnbuf, len); 168 169 else if (type == PARAVIRT_PATCH(pv_cpu_ops.iret) || 170 type == PARAVIRT_PATCH(pv_cpu_ops.usergs_sysret64)) 171 /* If operation requires a jmp, then jmp */ 172 ret = paravirt_patch_jmp(insnbuf, opfunc, addr, len); 173 else 174 /* Otherwise call the function; assume target could 175 clobber any caller-save reg */ 176 ret = paravirt_patch_call(insnbuf, opfunc, CLBR_ANY, 177 addr, clobbers, len); 178 179 return ret; 180 } 181 182 unsigned paravirt_patch_insns(void *insnbuf, unsigned len, 183 const char *start, const char *end) 184 { 185 unsigned insn_len = end - start; 186 187 if (insn_len > len || start == NULL) 188 insn_len = len; 189 else 190 memcpy(insnbuf, start, insn_len); 191 192 return insn_len; 193 } 194 195 static void native_flush_tlb(void) 196 { 197 __native_flush_tlb(); 198 } 199 200 /* 201 * Global pages have to be flushed a bit differently. Not a real 202 * performance problem because this does not happen often. 203 */ 204 static void native_flush_tlb_global(void) 205 { 206 __native_flush_tlb_global(); 207 } 208 209 static void native_flush_tlb_one_user(unsigned long addr) 210 { 211 __native_flush_tlb_one_user(addr); 212 } 213 214 struct static_key paravirt_steal_enabled; 215 struct static_key paravirt_steal_rq_enabled; 216 217 static u64 native_steal_clock(int cpu) 218 { 219 return 0; 220 } 221 222 /* These are in entry.S */ 223 extern void native_iret(void); 224 extern void native_usergs_sysret64(void); 225 226 static struct resource reserve_ioports = { 227 .start = 0, 228 .end = IO_SPACE_LIMIT, 229 .name = "paravirt-ioport", 230 .flags = IORESOURCE_IO | IORESOURCE_BUSY, 231 }; 232 233 /* 234 * Reserve the whole legacy IO space to prevent any legacy drivers 235 * from wasting time probing for their hardware. This is a fairly 236 * brute-force approach to disabling all non-virtual drivers. 237 * 238 * Note that this must be called very early to have any effect. 239 */ 240 int paravirt_disable_iospace(void) 241 { 242 return request_resource(&ioport_resource, &reserve_ioports); 243 } 244 245 static DEFINE_PER_CPU(enum paravirt_lazy_mode, paravirt_lazy_mode) = PARAVIRT_LAZY_NONE; 246 247 static inline void enter_lazy(enum paravirt_lazy_mode mode) 248 { 249 BUG_ON(this_cpu_read(paravirt_lazy_mode) != PARAVIRT_LAZY_NONE); 250 251 this_cpu_write(paravirt_lazy_mode, mode); 252 } 253 254 static void leave_lazy(enum paravirt_lazy_mode mode) 255 { 256 BUG_ON(this_cpu_read(paravirt_lazy_mode) != mode); 257 258 this_cpu_write(paravirt_lazy_mode, PARAVIRT_LAZY_NONE); 259 } 260 261 void paravirt_enter_lazy_mmu(void) 262 { 263 enter_lazy(PARAVIRT_LAZY_MMU); 264 } 265 266 void paravirt_leave_lazy_mmu(void) 267 { 268 leave_lazy(PARAVIRT_LAZY_MMU); 269 } 270 271 void paravirt_flush_lazy_mmu(void) 272 { 273 preempt_disable(); 274 275 if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) { 276 arch_leave_lazy_mmu_mode(); 277 arch_enter_lazy_mmu_mode(); 278 } 279 280 preempt_enable(); 281 } 282 283 void paravirt_start_context_switch(struct task_struct *prev) 284 { 285 BUG_ON(preemptible()); 286 287 if (this_cpu_read(paravirt_lazy_mode) == PARAVIRT_LAZY_MMU) { 288 arch_leave_lazy_mmu_mode(); 289 set_ti_thread_flag(task_thread_info(prev), TIF_LAZY_MMU_UPDATES); 290 } 291 enter_lazy(PARAVIRT_LAZY_CPU); 292 } 293 294 void paravirt_end_context_switch(struct task_struct *next) 295 { 296 BUG_ON(preemptible()); 297 298 leave_lazy(PARAVIRT_LAZY_CPU); 299 300 if (test_and_clear_ti_thread_flag(task_thread_info(next), TIF_LAZY_MMU_UPDATES)) 301 arch_enter_lazy_mmu_mode(); 302 } 303 304 enum paravirt_lazy_mode paravirt_get_lazy_mode(void) 305 { 306 if (in_interrupt()) 307 return PARAVIRT_LAZY_NONE; 308 309 return this_cpu_read(paravirt_lazy_mode); 310 } 311 312 struct pv_info pv_info = { 313 .name = "bare hardware", 314 .kernel_rpl = 0, 315 .shared_kernel_pmd = 1, /* Only used when CONFIG_X86_PAE is set */ 316 317 #ifdef CONFIG_X86_64 318 .extra_user_64bit_cs = __USER_CS, 319 #endif 320 }; 321 322 struct pv_init_ops pv_init_ops = { 323 .patch = native_patch, 324 }; 325 326 struct pv_time_ops pv_time_ops = { 327 .sched_clock = native_sched_clock, 328 .steal_clock = native_steal_clock, 329 }; 330 331 __visible struct pv_irq_ops pv_irq_ops = { 332 .save_fl = __PV_IS_CALLEE_SAVE(native_save_fl), 333 .restore_fl = __PV_IS_CALLEE_SAVE(native_restore_fl), 334 .irq_disable = __PV_IS_CALLEE_SAVE(native_irq_disable), 335 .irq_enable = __PV_IS_CALLEE_SAVE(native_irq_enable), 336 .safe_halt = native_safe_halt, 337 .halt = native_halt, 338 }; 339 340 __visible struct pv_cpu_ops pv_cpu_ops = { 341 .cpuid = native_cpuid, 342 .get_debugreg = native_get_debugreg, 343 .set_debugreg = native_set_debugreg, 344 .read_cr0 = native_read_cr0, 345 .write_cr0 = native_write_cr0, 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, 353 .write_msr = native_write_msr, 354 .read_msr_safe = native_read_msr_safe, 355 .write_msr_safe = native_write_msr_safe, 356 .read_pmc = native_read_pmc, 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_tr = native_store_tr, 362 .load_tls = native_load_tls, 363 #ifdef CONFIG_X86_64 364 .load_gs_index = native_load_gs_index, 365 #endif 366 .write_ldt_entry = native_write_ldt_entry, 367 .write_gdt_entry = native_write_gdt_entry, 368 .write_idt_entry = native_write_idt_entry, 369 370 .alloc_ldt = paravirt_nop, 371 .free_ldt = paravirt_nop, 372 373 .load_sp0 = native_load_sp0, 374 375 #ifdef CONFIG_X86_64 376 .usergs_sysret64 = native_usergs_sysret64, 377 #endif 378 .iret = native_iret, 379 .swapgs = native_swapgs, 380 381 .set_iopl_mask = native_set_iopl_mask, 382 .io_delay = native_io_delay, 383 384 .start_context_switch = paravirt_nop, 385 .end_context_switch = paravirt_nop, 386 }; 387 388 /* At this point, native_get/set_debugreg has real function entries */ 389 NOKPROBE_SYMBOL(native_get_debugreg); 390 NOKPROBE_SYMBOL(native_set_debugreg); 391 NOKPROBE_SYMBOL(native_load_idt); 392 393 #if defined(CONFIG_X86_32) && !defined(CONFIG_X86_PAE) 394 /* 32-bit pagetable entries */ 395 #define PTE_IDENT __PV_IS_CALLEE_SAVE(_paravirt_ident_32) 396 #else 397 /* 64-bit pagetable entries */ 398 #define PTE_IDENT __PV_IS_CALLEE_SAVE(_paravirt_ident_64) 399 #endif 400 401 struct pv_mmu_ops pv_mmu_ops __ro_after_init = { 402 403 .read_cr2 = native_read_cr2, 404 .write_cr2 = native_write_cr2, 405 .read_cr3 = __native_read_cr3, 406 .write_cr3 = native_write_cr3, 407 408 .flush_tlb_user = native_flush_tlb, 409 .flush_tlb_kernel = native_flush_tlb_global, 410 .flush_tlb_one_user = native_flush_tlb_one_user, 411 .flush_tlb_others = native_flush_tlb_others, 412 413 .pgd_alloc = __paravirt_pgd_alloc, 414 .pgd_free = paravirt_nop, 415 416 .alloc_pte = paravirt_nop, 417 .alloc_pmd = paravirt_nop, 418 .alloc_pud = paravirt_nop, 419 .alloc_p4d = paravirt_nop, 420 .release_pte = paravirt_nop, 421 .release_pmd = paravirt_nop, 422 .release_pud = paravirt_nop, 423 .release_p4d = paravirt_nop, 424 425 .set_pte = native_set_pte, 426 .set_pte_at = native_set_pte_at, 427 .set_pmd = native_set_pmd, 428 429 .ptep_modify_prot_start = __ptep_modify_prot_start, 430 .ptep_modify_prot_commit = __ptep_modify_prot_commit, 431 432 #if CONFIG_PGTABLE_LEVELS >= 3 433 #ifdef CONFIG_X86_PAE 434 .set_pte_atomic = native_set_pte_atomic, 435 .pte_clear = native_pte_clear, 436 .pmd_clear = native_pmd_clear, 437 #endif 438 .set_pud = native_set_pud, 439 440 .pmd_val = PTE_IDENT, 441 .make_pmd = PTE_IDENT, 442 443 #if CONFIG_PGTABLE_LEVELS >= 4 444 .pud_val = PTE_IDENT, 445 .make_pud = PTE_IDENT, 446 447 .set_p4d = native_set_p4d, 448 449 #if CONFIG_PGTABLE_LEVELS >= 5 450 .p4d_val = PTE_IDENT, 451 .make_p4d = PTE_IDENT, 452 453 .set_pgd = native_set_pgd, 454 #endif /* CONFIG_PGTABLE_LEVELS >= 5 */ 455 #endif /* CONFIG_PGTABLE_LEVELS >= 4 */ 456 #endif /* CONFIG_PGTABLE_LEVELS >= 3 */ 457 458 .pte_val = PTE_IDENT, 459 .pgd_val = PTE_IDENT, 460 461 .make_pte = PTE_IDENT, 462 .make_pgd = PTE_IDENT, 463 464 .dup_mmap = paravirt_nop, 465 .exit_mmap = paravirt_nop, 466 .activate_mm = paravirt_nop, 467 468 .lazy_mode = { 469 .enter = paravirt_nop, 470 .leave = paravirt_nop, 471 .flush = paravirt_nop, 472 }, 473 474 .set_fixmap = native_set_fixmap, 475 }; 476 477 EXPORT_SYMBOL_GPL(pv_time_ops); 478 EXPORT_SYMBOL (pv_cpu_ops); 479 EXPORT_SYMBOL (pv_mmu_ops); 480 EXPORT_SYMBOL_GPL(pv_info); 481 EXPORT_SYMBOL (pv_irq_ops); 482