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 /* 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_mmu_ops = pv_mmu_ops, 128 #ifdef CONFIG_PARAVIRT_SPINLOCKS 129 .pv_lock_ops = pv_lock_ops, 130 #endif 131 }; 132 return *((void **)&tmpl + type); 133 } 134 135 unsigned paravirt_patch_default(u8 type, u16 clobbers, void *insnbuf, 136 unsigned long addr, unsigned len) 137 { 138 void *opfunc = get_call_destination(type); 139 unsigned ret; 140 141 if (opfunc == NULL) 142 /* If there's no function, patch it with a ud2a (BUG) */ 143 ret = paravirt_patch_insns(insnbuf, len, ud2a, ud2a+sizeof(ud2a)); 144 else if (opfunc == _paravirt_nop) 145 ret = 0; 146 147 /* identity functions just return their single argument */ 148 else if (opfunc == _paravirt_ident_32) 149 ret = paravirt_patch_ident_32(insnbuf, len); 150 else if (opfunc == _paravirt_ident_64) 151 ret = paravirt_patch_ident_64(insnbuf, len); 152 153 else if (type == PARAVIRT_PATCH(pv_cpu_ops.iret) || 154 type == PARAVIRT_PATCH(pv_cpu_ops.usergs_sysret64)) 155 /* If operation requires a jmp, then jmp */ 156 ret = paravirt_patch_jmp(insnbuf, opfunc, addr, len); 157 else 158 /* Otherwise call the function; assume target could 159 clobber any caller-save reg */ 160 ret = paravirt_patch_call(insnbuf, opfunc, CLBR_ANY, 161 addr, clobbers, len); 162 163 return ret; 164 } 165 166 unsigned paravirt_patch_insns(void *insnbuf, unsigned len, 167 const char *start, const char *end) 168 { 169 unsigned insn_len = end - start; 170 171 if (insn_len > len || start == NULL) 172 insn_len = len; 173 else 174 memcpy(insnbuf, start, insn_len); 175 176 return insn_len; 177 } 178 179 static void native_flush_tlb(void) 180 { 181 __native_flush_tlb(); 182 } 183 184 /* 185 * Global pages have to be flushed a bit differently. Not a real 186 * performance problem because this does not happen often. 187 */ 188 static void native_flush_tlb_global(void) 189 { 190 __native_flush_tlb_global(); 191 } 192 193 static void native_flush_tlb_single(unsigned long addr) 194 { 195 __native_flush_tlb_single(addr); 196 } 197 198 struct static_key paravirt_steal_enabled; 199 struct static_key paravirt_steal_rq_enabled; 200 201 static u64 native_steal_clock(int cpu) 202 { 203 return 0; 204 } 205 206 /* These are in entry.S */ 207 extern void native_iret(void); 208 extern void native_usergs_sysret64(void); 209 210 static struct resource reserve_ioports = { 211 .start = 0, 212 .end = IO_SPACE_LIMIT, 213 .name = "paravirt-ioport", 214 .flags = IORESOURCE_IO | IORESOURCE_BUSY, 215 }; 216 217 /* 218 * Reserve the whole legacy IO space to prevent any legacy drivers 219 * from wasting time probing for their hardware. This is a fairly 220 * brute-force approach to disabling all non-virtual drivers. 221 * 222 * Note that this must be called very early to have any effect. 223 */ 224 int paravirt_disable_iospace(void) 225 { 226 return request_resource(&ioport_resource, &reserve_ioports); 227 } 228 229 static DEFINE_PER_CPU(enum paravirt_lazy_mode, paravirt_lazy_mode) = PARAVIRT_LAZY_NONE; 230 231 static inline void enter_lazy(enum paravirt_lazy_mode mode) 232 { 233 BUG_ON(this_cpu_read(paravirt_lazy_mode) != PARAVIRT_LAZY_NONE); 234 235 this_cpu_write(paravirt_lazy_mode, mode); 236 } 237 238 static void leave_lazy(enum paravirt_lazy_mode mode) 239 { 240 BUG_ON(this_cpu_read(paravirt_lazy_mode) != mode); 241 242 this_cpu_write(paravirt_lazy_mode, PARAVIRT_LAZY_NONE); 243 } 244 245 void paravirt_enter_lazy_mmu(void) 246 { 247 enter_lazy(PARAVIRT_LAZY_MMU); 248 } 249 250 void paravirt_leave_lazy_mmu(void) 251 { 252 leave_lazy(PARAVIRT_LAZY_MMU); 253 } 254 255 void paravirt_flush_lazy_mmu(void) 256 { 257 preempt_disable(); 258 259 if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) { 260 arch_leave_lazy_mmu_mode(); 261 arch_enter_lazy_mmu_mode(); 262 } 263 264 preempt_enable(); 265 } 266 267 void paravirt_start_context_switch(struct task_struct *prev) 268 { 269 BUG_ON(preemptible()); 270 271 if (this_cpu_read(paravirt_lazy_mode) == PARAVIRT_LAZY_MMU) { 272 arch_leave_lazy_mmu_mode(); 273 set_ti_thread_flag(task_thread_info(prev), TIF_LAZY_MMU_UPDATES); 274 } 275 enter_lazy(PARAVIRT_LAZY_CPU); 276 } 277 278 void paravirt_end_context_switch(struct task_struct *next) 279 { 280 BUG_ON(preemptible()); 281 282 leave_lazy(PARAVIRT_LAZY_CPU); 283 284 if (test_and_clear_ti_thread_flag(task_thread_info(next), TIF_LAZY_MMU_UPDATES)) 285 arch_enter_lazy_mmu_mode(); 286 } 287 288 enum paravirt_lazy_mode paravirt_get_lazy_mode(void) 289 { 290 if (in_interrupt()) 291 return PARAVIRT_LAZY_NONE; 292 293 return this_cpu_read(paravirt_lazy_mode); 294 } 295 296 struct pv_info pv_info = { 297 .name = "bare hardware", 298 .kernel_rpl = 0, 299 .shared_kernel_pmd = 1, /* Only used when CONFIG_X86_PAE is set */ 300 301 #ifdef CONFIG_X86_64 302 .extra_user_64bit_cs = __USER_CS, 303 #endif 304 }; 305 306 struct pv_init_ops pv_init_ops = { 307 .patch = native_patch, 308 }; 309 310 struct pv_time_ops pv_time_ops = { 311 .sched_clock = native_sched_clock, 312 .steal_clock = native_steal_clock, 313 }; 314 315 __visible struct pv_irq_ops pv_irq_ops = { 316 .save_fl = __PV_IS_CALLEE_SAVE(native_save_fl), 317 .restore_fl = __PV_IS_CALLEE_SAVE(native_restore_fl), 318 .irq_disable = __PV_IS_CALLEE_SAVE(native_irq_disable), 319 .irq_enable = __PV_IS_CALLEE_SAVE(native_irq_enable), 320 .safe_halt = native_safe_halt, 321 .halt = native_halt, 322 #ifdef CONFIG_X86_64 323 .adjust_exception_frame = paravirt_nop, 324 #endif 325 }; 326 327 __visible struct pv_cpu_ops pv_cpu_ops = { 328 .cpuid = native_cpuid, 329 .get_debugreg = native_get_debugreg, 330 .set_debugreg = native_set_debugreg, 331 .clts = native_clts, 332 .read_cr0 = native_read_cr0, 333 .write_cr0 = native_write_cr0, 334 .read_cr4 = native_read_cr4, 335 .write_cr4 = native_write_cr4, 336 #ifdef CONFIG_X86_64 337 .read_cr8 = native_read_cr8, 338 .write_cr8 = native_write_cr8, 339 #endif 340 .wbinvd = native_wbinvd, 341 .read_msr = native_read_msr, 342 .write_msr = native_write_msr, 343 .read_msr_safe = native_read_msr_safe, 344 .write_msr_safe = native_write_msr_safe, 345 .read_pmc = native_read_pmc, 346 .load_tr_desc = native_load_tr_desc, 347 .set_ldt = native_set_ldt, 348 .load_gdt = native_load_gdt, 349 .load_idt = native_load_idt, 350 .store_idt = native_store_idt, 351 .store_tr = native_store_tr, 352 .load_tls = native_load_tls, 353 #ifdef CONFIG_X86_64 354 .load_gs_index = native_load_gs_index, 355 #endif 356 .write_ldt_entry = native_write_ldt_entry, 357 .write_gdt_entry = native_write_gdt_entry, 358 .write_idt_entry = native_write_idt_entry, 359 360 .alloc_ldt = paravirt_nop, 361 .free_ldt = paravirt_nop, 362 363 .load_sp0 = native_load_sp0, 364 365 #ifdef CONFIG_X86_64 366 .usergs_sysret64 = native_usergs_sysret64, 367 #endif 368 .iret = native_iret, 369 .swapgs = native_swapgs, 370 371 .set_iopl_mask = native_set_iopl_mask, 372 .io_delay = native_io_delay, 373 374 .start_context_switch = paravirt_nop, 375 .end_context_switch = paravirt_nop, 376 }; 377 378 /* At this point, native_get/set_debugreg has real function entries */ 379 NOKPROBE_SYMBOL(native_get_debugreg); 380 NOKPROBE_SYMBOL(native_set_debugreg); 381 NOKPROBE_SYMBOL(native_load_idt); 382 383 #if defined(CONFIG_X86_32) && !defined(CONFIG_X86_PAE) 384 /* 32-bit pagetable entries */ 385 #define PTE_IDENT __PV_IS_CALLEE_SAVE(_paravirt_ident_32) 386 #else 387 /* 64-bit pagetable entries */ 388 #define PTE_IDENT __PV_IS_CALLEE_SAVE(_paravirt_ident_64) 389 #endif 390 391 struct pv_mmu_ops pv_mmu_ops __ro_after_init = { 392 393 .read_cr2 = native_read_cr2, 394 .write_cr2 = native_write_cr2, 395 .read_cr3 = native_read_cr3, 396 .write_cr3 = native_write_cr3, 397 398 .flush_tlb_user = native_flush_tlb, 399 .flush_tlb_kernel = native_flush_tlb_global, 400 .flush_tlb_single = native_flush_tlb_single, 401 .flush_tlb_others = native_flush_tlb_others, 402 403 .pgd_alloc = __paravirt_pgd_alloc, 404 .pgd_free = paravirt_nop, 405 406 .alloc_pte = paravirt_nop, 407 .alloc_pmd = paravirt_nop, 408 .alloc_pud = paravirt_nop, 409 .release_pte = paravirt_nop, 410 .release_pmd = paravirt_nop, 411 .release_pud = paravirt_nop, 412 413 .set_pte = native_set_pte, 414 .set_pte_at = native_set_pte_at, 415 .set_pmd = native_set_pmd, 416 .set_pmd_at = native_set_pmd_at, 417 .pte_update = paravirt_nop, 418 419 .ptep_modify_prot_start = __ptep_modify_prot_start, 420 .ptep_modify_prot_commit = __ptep_modify_prot_commit, 421 422 #if CONFIG_PGTABLE_LEVELS >= 3 423 #ifdef CONFIG_X86_PAE 424 .set_pte_atomic = native_set_pte_atomic, 425 .pte_clear = native_pte_clear, 426 .pmd_clear = native_pmd_clear, 427 #endif 428 .set_pud = native_set_pud, 429 430 .pmd_val = PTE_IDENT, 431 .make_pmd = PTE_IDENT, 432 433 #if CONFIG_PGTABLE_LEVELS == 4 434 .pud_val = PTE_IDENT, 435 .make_pud = PTE_IDENT, 436 437 .set_pgd = native_set_pgd, 438 #endif 439 #endif /* CONFIG_PGTABLE_LEVELS >= 3 */ 440 441 .pte_val = PTE_IDENT, 442 .pgd_val = PTE_IDENT, 443 444 .make_pte = PTE_IDENT, 445 .make_pgd = PTE_IDENT, 446 447 .dup_mmap = paravirt_nop, 448 .exit_mmap = paravirt_nop, 449 .activate_mm = paravirt_nop, 450 451 .lazy_mode = { 452 .enter = paravirt_nop, 453 .leave = paravirt_nop, 454 .flush = paravirt_nop, 455 }, 456 457 .set_fixmap = native_set_fixmap, 458 }; 459 460 EXPORT_SYMBOL_GPL(pv_time_ops); 461 EXPORT_SYMBOL (pv_cpu_ops); 462 EXPORT_SYMBOL (pv_mmu_ops); 463 EXPORT_SYMBOL_GPL(pv_info); 464 EXPORT_SYMBOL (pv_irq_ops); 465