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 (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 DEFINE_STATIC_KEY_TRUE(virt_spin_lock_key); 119 120 void __init native_pv_lock_init(void) 121 { 122 if (!static_cpu_has(X86_FEATURE_HYPERVISOR)) 123 static_branch_disable(&virt_spin_lock_key); 124 } 125 126 /* 127 * Neat trick to map patch type back to the call within the 128 * corresponding structure. 129 */ 130 static void *get_call_destination(u8 type) 131 { 132 struct paravirt_patch_template tmpl = { 133 .pv_init_ops = pv_init_ops, 134 .pv_time_ops = pv_time_ops, 135 .pv_cpu_ops = pv_cpu_ops, 136 .pv_irq_ops = pv_irq_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 ret = 0; 156 157 /* identity functions just return their single argument */ 158 else if (opfunc == _paravirt_ident_32) 159 ret = paravirt_patch_ident_32(insnbuf, len); 160 else if (opfunc == _paravirt_ident_64) 161 ret = paravirt_patch_ident_64(insnbuf, len); 162 163 else if (type == PARAVIRT_PATCH(pv_cpu_ops.iret) || 164 type == PARAVIRT_PATCH(pv_cpu_ops.usergs_sysret64)) 165 /* If operation requires a jmp, then jmp */ 166 ret = paravirt_patch_jmp(insnbuf, opfunc, addr, len); 167 else 168 /* Otherwise call the function; assume target could 169 clobber any caller-save reg */ 170 ret = paravirt_patch_call(insnbuf, opfunc, CLBR_ANY, 171 addr, clobbers, len); 172 173 return ret; 174 } 175 176 unsigned paravirt_patch_insns(void *insnbuf, unsigned len, 177 const char *start, const char *end) 178 { 179 unsigned insn_len = end - start; 180 181 if (insn_len > len || start == NULL) 182 insn_len = len; 183 else 184 memcpy(insnbuf, start, insn_len); 185 186 return insn_len; 187 } 188 189 static void native_flush_tlb(void) 190 { 191 __native_flush_tlb(); 192 } 193 194 /* 195 * Global pages have to be flushed a bit differently. Not a real 196 * performance problem because this does not happen often. 197 */ 198 static void native_flush_tlb_global(void) 199 { 200 __native_flush_tlb_global(); 201 } 202 203 static void native_flush_tlb_one_user(unsigned long addr) 204 { 205 __native_flush_tlb_one_user(addr); 206 } 207 208 struct static_key paravirt_steal_enabled; 209 struct static_key paravirt_steal_rq_enabled; 210 211 static u64 native_steal_clock(int cpu) 212 { 213 return 0; 214 } 215 216 /* These are in entry.S */ 217 extern void native_iret(void); 218 extern void native_usergs_sysret64(void); 219 220 static struct resource reserve_ioports = { 221 .start = 0, 222 .end = IO_SPACE_LIMIT, 223 .name = "paravirt-ioport", 224 .flags = IORESOURCE_IO | IORESOURCE_BUSY, 225 }; 226 227 /* 228 * Reserve the whole legacy IO space to prevent any legacy drivers 229 * from wasting time probing for their hardware. This is a fairly 230 * brute-force approach to disabling all non-virtual drivers. 231 * 232 * Note that this must be called very early to have any effect. 233 */ 234 int paravirt_disable_iospace(void) 235 { 236 return request_resource(&ioport_resource, &reserve_ioports); 237 } 238 239 static DEFINE_PER_CPU(enum paravirt_lazy_mode, paravirt_lazy_mode) = PARAVIRT_LAZY_NONE; 240 241 static inline void enter_lazy(enum paravirt_lazy_mode mode) 242 { 243 BUG_ON(this_cpu_read(paravirt_lazy_mode) != PARAVIRT_LAZY_NONE); 244 245 this_cpu_write(paravirt_lazy_mode, mode); 246 } 247 248 static void leave_lazy(enum paravirt_lazy_mode mode) 249 { 250 BUG_ON(this_cpu_read(paravirt_lazy_mode) != mode); 251 252 this_cpu_write(paravirt_lazy_mode, PARAVIRT_LAZY_NONE); 253 } 254 255 void paravirt_enter_lazy_mmu(void) 256 { 257 enter_lazy(PARAVIRT_LAZY_MMU); 258 } 259 260 void paravirt_leave_lazy_mmu(void) 261 { 262 leave_lazy(PARAVIRT_LAZY_MMU); 263 } 264 265 void paravirt_flush_lazy_mmu(void) 266 { 267 preempt_disable(); 268 269 if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) { 270 arch_leave_lazy_mmu_mode(); 271 arch_enter_lazy_mmu_mode(); 272 } 273 274 preempt_enable(); 275 } 276 277 void paravirt_start_context_switch(struct task_struct *prev) 278 { 279 BUG_ON(preemptible()); 280 281 if (this_cpu_read(paravirt_lazy_mode) == PARAVIRT_LAZY_MMU) { 282 arch_leave_lazy_mmu_mode(); 283 set_ti_thread_flag(task_thread_info(prev), TIF_LAZY_MMU_UPDATES); 284 } 285 enter_lazy(PARAVIRT_LAZY_CPU); 286 } 287 288 void paravirt_end_context_switch(struct task_struct *next) 289 { 290 BUG_ON(preemptible()); 291 292 leave_lazy(PARAVIRT_LAZY_CPU); 293 294 if (test_and_clear_ti_thread_flag(task_thread_info(next), TIF_LAZY_MMU_UPDATES)) 295 arch_enter_lazy_mmu_mode(); 296 } 297 298 enum paravirt_lazy_mode paravirt_get_lazy_mode(void) 299 { 300 if (in_interrupt()) 301 return PARAVIRT_LAZY_NONE; 302 303 return this_cpu_read(paravirt_lazy_mode); 304 } 305 306 struct pv_info pv_info = { 307 .name = "bare hardware", 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 }; 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 .read_cr0 = native_read_cr0, 339 .write_cr0 = native_write_cr0, 340 .write_cr4 = native_write_cr4, 341 #ifdef CONFIG_X86_64 342 .read_cr8 = native_read_cr8, 343 .write_cr8 = native_write_cr8, 344 #endif 345 .wbinvd = native_wbinvd, 346 .read_msr = native_read_msr, 347 .write_msr = native_write_msr, 348 .read_msr_safe = native_read_msr_safe, 349 .write_msr_safe = native_write_msr_safe, 350 .read_pmc = native_read_pmc, 351 .load_tr_desc = native_load_tr_desc, 352 .set_ldt = native_set_ldt, 353 .load_gdt = native_load_gdt, 354 .load_idt = native_load_idt, 355 .store_tr = native_store_tr, 356 .load_tls = native_load_tls, 357 #ifdef CONFIG_X86_64 358 .load_gs_index = native_load_gs_index, 359 #endif 360 .write_ldt_entry = native_write_ldt_entry, 361 .write_gdt_entry = native_write_gdt_entry, 362 .write_idt_entry = native_write_idt_entry, 363 364 .alloc_ldt = paravirt_nop, 365 .free_ldt = paravirt_nop, 366 367 .load_sp0 = native_load_sp0, 368 369 #ifdef CONFIG_X86_64 370 .usergs_sysret64 = native_usergs_sysret64, 371 #endif 372 .iret = native_iret, 373 .swapgs = native_swapgs, 374 375 .set_iopl_mask = native_set_iopl_mask, 376 .io_delay = native_io_delay, 377 378 .start_context_switch = paravirt_nop, 379 .end_context_switch = paravirt_nop, 380 }; 381 382 /* At this point, native_get/set_debugreg has real function entries */ 383 NOKPROBE_SYMBOL(native_get_debugreg); 384 NOKPROBE_SYMBOL(native_set_debugreg); 385 NOKPROBE_SYMBOL(native_load_idt); 386 387 #if defined(CONFIG_X86_32) && !defined(CONFIG_X86_PAE) 388 /* 32-bit pagetable entries */ 389 #define PTE_IDENT __PV_IS_CALLEE_SAVE(_paravirt_ident_32) 390 #else 391 /* 64-bit pagetable entries */ 392 #define PTE_IDENT __PV_IS_CALLEE_SAVE(_paravirt_ident_64) 393 #endif 394 395 struct pv_mmu_ops pv_mmu_ops __ro_after_init = { 396 397 .read_cr2 = native_read_cr2, 398 .write_cr2 = native_write_cr2, 399 .read_cr3 = __native_read_cr3, 400 .write_cr3 = native_write_cr3, 401 402 .flush_tlb_user = native_flush_tlb, 403 .flush_tlb_kernel = native_flush_tlb_global, 404 .flush_tlb_one_user = native_flush_tlb_one_user, 405 .flush_tlb_others = native_flush_tlb_others, 406 407 .pgd_alloc = __paravirt_pgd_alloc, 408 .pgd_free = paravirt_nop, 409 410 .alloc_pte = paravirt_nop, 411 .alloc_pmd = paravirt_nop, 412 .alloc_pud = paravirt_nop, 413 .alloc_p4d = paravirt_nop, 414 .release_pte = paravirt_nop, 415 .release_pmd = paravirt_nop, 416 .release_pud = paravirt_nop, 417 .release_p4d = paravirt_nop, 418 419 .set_pte = native_set_pte, 420 .set_pte_at = native_set_pte_at, 421 .set_pmd = native_set_pmd, 422 423 .ptep_modify_prot_start = __ptep_modify_prot_start, 424 .ptep_modify_prot_commit = __ptep_modify_prot_commit, 425 426 #if CONFIG_PGTABLE_LEVELS >= 3 427 #ifdef CONFIG_X86_PAE 428 .set_pte_atomic = native_set_pte_atomic, 429 .pte_clear = native_pte_clear, 430 .pmd_clear = native_pmd_clear, 431 #endif 432 .set_pud = native_set_pud, 433 434 .pmd_val = PTE_IDENT, 435 .make_pmd = PTE_IDENT, 436 437 #if CONFIG_PGTABLE_LEVELS >= 4 438 .pud_val = PTE_IDENT, 439 .make_pud = PTE_IDENT, 440 441 .set_p4d = native_set_p4d, 442 443 #if CONFIG_PGTABLE_LEVELS >= 5 444 .p4d_val = PTE_IDENT, 445 .make_p4d = PTE_IDENT, 446 447 .set_pgd = native_set_pgd, 448 #endif /* CONFIG_PGTABLE_LEVELS >= 5 */ 449 #endif /* CONFIG_PGTABLE_LEVELS >= 4 */ 450 #endif /* CONFIG_PGTABLE_LEVELS >= 3 */ 451 452 .pte_val = PTE_IDENT, 453 .pgd_val = PTE_IDENT, 454 455 .make_pte = PTE_IDENT, 456 .make_pgd = PTE_IDENT, 457 458 .dup_mmap = paravirt_nop, 459 .exit_mmap = paravirt_nop, 460 .activate_mm = paravirt_nop, 461 462 .lazy_mode = { 463 .enter = paravirt_nop, 464 .leave = paravirt_nop, 465 .flush = paravirt_nop, 466 }, 467 468 .set_fixmap = native_set_fixmap, 469 }; 470 471 EXPORT_SYMBOL_GPL(pv_time_ops); 472 EXPORT_SYMBOL (pv_cpu_ops); 473 EXPORT_SYMBOL (pv_mmu_ops); 474 EXPORT_SYMBOL_GPL(pv_info); 475 EXPORT_SYMBOL (pv_irq_ops); 476