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/* 45 * nop stub, which must not clobber anything *including the stack* to 46 * avoid confusing the entry prologues. 47 */ 48extern void _paravirt_nop(void); 49asm (".pushsection .entry.text, \"ax\"\n" 50 ".global _paravirt_nop\n" 51 "_paravirt_nop:\n\t" 52 "ret\n\t" 53 ".size _paravirt_nop, . - _paravirt_nop\n\t" 54 ".type _paravirt_nop, @function\n\t" 55 ".popsection"); 56 57/* identity function, which can be inlined */ 58u32 _paravirt_ident_32(u32 x) 59{ 60 return x; 61} 62 63u64 _paravirt_ident_64(u64 x) 64{ 65 return x; 66} 67 68void __init default_banner(void) 69{ 70 printk(KERN_INFO "Booting paravirtualized kernel on %s\n", 71 pv_info.name); 72} 73 74/* Undefined instruction for dealing with missing ops pointers. */ 75static const unsigned char ud2a[] = { 0x0f, 0x0b }; 76 77unsigned paravirt_patch_nop(void) 78{ 79 return 0; 80} 81 82unsigned paravirt_patch_ignore(unsigned len) 83{ 84 return len; 85} 86 87struct branch { 88 unsigned char opcode; 89 u32 delta; 90} __attribute__((packed)); 91 92unsigned paravirt_patch_call(void *insnbuf, 93 const void *target, u16 tgt_clobbers, 94 unsigned long addr, u16 site_clobbers, 95 unsigned len) 96{ 97 struct branch *b = insnbuf; 98 unsigned long delta = (unsigned long)target - (addr+5); 99 100 if (tgt_clobbers & ~site_clobbers) 101 return len; /* target would clobber too much for this site */ 102 if (len < 5) 103 return len; /* call too long for patch site */ 104 105 b->opcode = 0xe8; /* call */ 106 b->delta = delta; 107 BUILD_BUG_ON(sizeof(*b) != 5); 108 109 return 5; 110} 111 112unsigned paravirt_patch_jmp(void *insnbuf, const void *target, 113 unsigned long addr, unsigned len) 114{ 115 struct branch *b = insnbuf; 116 unsigned long delta = (unsigned long)target - (addr+5); 117 118 if (len < 5) 119 return len; /* call too long for patch site */ 120 121 b->opcode = 0xe9; /* jmp */ 122 b->delta = delta; 123 124 return 5; 125} 126 127/* Neat trick to map patch type back to the call within the 128 * corresponding structure. */ 129static void *get_call_destination(u8 type) 130{ 131 struct paravirt_patch_template tmpl = { 132 .pv_init_ops = pv_init_ops, 133 .pv_time_ops = pv_time_ops, 134 .pv_cpu_ops = pv_cpu_ops, 135 .pv_irq_ops = pv_irq_ops, 136 .pv_apic_ops = pv_apic_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 145unsigned 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 /* If the operation is a nop, then nop the callsite */ 156 ret = paravirt_patch_nop(); 157 158 /* identity functions just return their single argument */ 159 else if (opfunc == _paravirt_ident_32) 160 ret = paravirt_patch_ident_32(insnbuf, len); 161 else if (opfunc == _paravirt_ident_64) 162 ret = paravirt_patch_ident_64(insnbuf, len); 163 164 else if (type == PARAVIRT_PATCH(pv_cpu_ops.iret) || 165 type == PARAVIRT_PATCH(pv_cpu_ops.irq_enable_sysexit) || 166 type == PARAVIRT_PATCH(pv_cpu_ops.usergs_sysret32) || 167 type == PARAVIRT_PATCH(pv_cpu_ops.usergs_sysret64)) 168 /* If operation requires a jmp, then jmp */ 169 ret = paravirt_patch_jmp(insnbuf, opfunc, addr, len); 170 else 171 /* Otherwise call the function; assume target could 172 clobber any caller-save reg */ 173 ret = paravirt_patch_call(insnbuf, opfunc, CLBR_ANY, 174 addr, clobbers, len); 175 176 return ret; 177} 178 179unsigned paravirt_patch_insns(void *insnbuf, unsigned len, 180 const char *start, const char *end) 181{ 182 unsigned insn_len = end - start; 183 184 if (insn_len > len || start == NULL) 185 insn_len = len; 186 else 187 memcpy(insnbuf, start, insn_len); 188 189 return insn_len; 190} 191 192static void native_flush_tlb(void) 193{ 194 __native_flush_tlb(); 195} 196 197/* 198 * Global pages have to be flushed a bit differently. Not a real 199 * performance problem because this does not happen often. 200 */ 201static void native_flush_tlb_global(void) 202{ 203 __native_flush_tlb_global(); 204} 205 206static void native_flush_tlb_single(unsigned long addr) 207{ 208 __native_flush_tlb_single(addr); 209} 210 211struct static_key paravirt_steal_enabled; 212struct static_key paravirt_steal_rq_enabled; 213 214static u64 native_steal_clock(int cpu) 215{ 216 return 0; 217} 218 219/* These are in entry.S */ 220extern void native_iret(void); 221extern void native_irq_enable_sysexit(void); 222extern void native_usergs_sysret32(void); 223extern void native_usergs_sysret64(void); 224 225static struct resource reserve_ioports = { 226 .start = 0, 227 .end = IO_SPACE_LIMIT, 228 .name = "paravirt-ioport", 229 .flags = IORESOURCE_IO | IORESOURCE_BUSY, 230}; 231 232/* 233 * Reserve the whole legacy IO space to prevent any legacy drivers 234 * from wasting time probing for their hardware. This is a fairly 235 * brute-force approach to disabling all non-virtual drivers. 236 * 237 * Note that this must be called very early to have any effect. 238 */ 239int paravirt_disable_iospace(void) 240{ 241 return request_resource(&ioport_resource, &reserve_ioports); 242} 243 244static DEFINE_PER_CPU(enum paravirt_lazy_mode, paravirt_lazy_mode) = PARAVIRT_LAZY_NONE; 245 246static inline void enter_lazy(enum paravirt_lazy_mode mode) 247{ 248 BUG_ON(this_cpu_read(paravirt_lazy_mode) != PARAVIRT_LAZY_NONE); 249 250 this_cpu_write(paravirt_lazy_mode, mode); 251} 252 253static void leave_lazy(enum paravirt_lazy_mode mode) 254{ 255 BUG_ON(this_cpu_read(paravirt_lazy_mode) != mode); 256 257 this_cpu_write(paravirt_lazy_mode, PARAVIRT_LAZY_NONE); 258} 259 260void paravirt_enter_lazy_mmu(void) 261{ 262 enter_lazy(PARAVIRT_LAZY_MMU); 263} 264 265void paravirt_leave_lazy_mmu(void) 266{ 267 leave_lazy(PARAVIRT_LAZY_MMU); 268} 269 270void paravirt_flush_lazy_mmu(void) 271{ 272 preempt_disable(); 273 274 if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) { 275 arch_leave_lazy_mmu_mode(); 276 arch_enter_lazy_mmu_mode(); 277 } 278 279 preempt_enable(); 280} 281 282void paravirt_start_context_switch(struct task_struct *prev) 283{ 284 BUG_ON(preemptible()); 285 286 if (this_cpu_read(paravirt_lazy_mode) == PARAVIRT_LAZY_MMU) { 287 arch_leave_lazy_mmu_mode(); 288 set_ti_thread_flag(task_thread_info(prev), TIF_LAZY_MMU_UPDATES); 289 } 290 enter_lazy(PARAVIRT_LAZY_CPU); 291} 292 293void paravirt_end_context_switch(struct task_struct *next) 294{ 295 BUG_ON(preemptible()); 296 297 leave_lazy(PARAVIRT_LAZY_CPU); 298 299 if (test_and_clear_ti_thread_flag(task_thread_info(next), TIF_LAZY_MMU_UPDATES)) 300 arch_enter_lazy_mmu_mode(); 301} 302 303enum paravirt_lazy_mode paravirt_get_lazy_mode(void) 304{ 305 if (in_interrupt()) 306 return PARAVIRT_LAZY_NONE; 307 308 return this_cpu_read(paravirt_lazy_mode); 309} 310 311struct pv_info pv_info = { 312 .name = "bare hardware", 313 .paravirt_enabled = 0, 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 322struct pv_init_ops pv_init_ops = { 323 .patch = native_patch, 324}; 325 326struct 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#ifdef CONFIG_X86_64 339 .adjust_exception_frame = paravirt_nop, 340#endif 341}; 342 343__visible struct pv_cpu_ops pv_cpu_ops = { 344 .cpuid = native_cpuid, 345 .get_debugreg = native_get_debugreg, 346 .set_debugreg = native_set_debugreg, 347 .clts = native_clts, 348 .read_cr0 = native_read_cr0, 349 .write_cr0 = native_write_cr0, 350 .read_cr4 = native_read_cr4, 351 .read_cr4_safe = native_read_cr4_safe, 352 .write_cr4 = native_write_cr4, 353#ifdef CONFIG_X86_64 354 .read_cr8 = native_read_cr8, 355 .write_cr8 = native_write_cr8, 356#endif 357 .wbinvd = native_wbinvd, 358 .read_msr = native_read_msr_safe, 359 .write_msr = native_write_msr_safe, 360 .read_tsc = native_read_tsc, 361 .read_pmc = native_read_pmc, 362 .read_tscp = native_read_tscp, 363 .load_tr_desc = native_load_tr_desc, 364 .set_ldt = native_set_ldt, 365 .load_gdt = native_load_gdt, 366 .load_idt = native_load_idt, 367 .store_idt = native_store_idt, 368 .store_tr = native_store_tr, 369 .load_tls = native_load_tls, 370#ifdef CONFIG_X86_64 371 .load_gs_index = native_load_gs_index, 372#endif 373 .write_ldt_entry = native_write_ldt_entry, 374 .write_gdt_entry = native_write_gdt_entry, 375 .write_idt_entry = native_write_idt_entry, 376 377 .alloc_ldt = paravirt_nop, 378 .free_ldt = paravirt_nop, 379 380 .load_sp0 = native_load_sp0, 381 382#if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION) 383 .irq_enable_sysexit = native_irq_enable_sysexit, 384#endif 385#ifdef CONFIG_X86_64 386#ifdef CONFIG_IA32_EMULATION 387 .usergs_sysret32 = native_usergs_sysret32, 388#endif 389 .usergs_sysret64 = native_usergs_sysret64, 390#endif 391 .iret = native_iret, 392 .swapgs = native_swapgs, 393 394 .set_iopl_mask = native_set_iopl_mask, 395 .io_delay = native_io_delay, 396 397 .start_context_switch = paravirt_nop, 398 .end_context_switch = paravirt_nop, 399}; 400 401/* At this point, native_get/set_debugreg has real function entries */ 402NOKPROBE_SYMBOL(native_get_debugreg); 403NOKPROBE_SYMBOL(native_set_debugreg); 404NOKPROBE_SYMBOL(native_load_idt); 405 406struct pv_apic_ops pv_apic_ops = { 407#ifdef CONFIG_X86_LOCAL_APIC 408 .startup_ipi_hook = paravirt_nop, 409#endif 410}; 411 412#if defined(CONFIG_X86_32) && !defined(CONFIG_X86_PAE) 413/* 32-bit pagetable entries */ 414#define PTE_IDENT __PV_IS_CALLEE_SAVE(_paravirt_ident_32) 415#else 416/* 64-bit pagetable entries */ 417#define PTE_IDENT __PV_IS_CALLEE_SAVE(_paravirt_ident_64) 418#endif 419 420struct pv_mmu_ops pv_mmu_ops = { 421 422 .read_cr2 = native_read_cr2, 423 .write_cr2 = native_write_cr2, 424 .read_cr3 = native_read_cr3, 425 .write_cr3 = native_write_cr3, 426 427 .flush_tlb_user = native_flush_tlb, 428 .flush_tlb_kernel = native_flush_tlb_global, 429 .flush_tlb_single = native_flush_tlb_single, 430 .flush_tlb_others = native_flush_tlb_others, 431 432 .pgd_alloc = __paravirt_pgd_alloc, 433 .pgd_free = paravirt_nop, 434 435 .alloc_pte = paravirt_nop, 436 .alloc_pmd = paravirt_nop, 437 .alloc_pud = paravirt_nop, 438 .release_pte = paravirt_nop, 439 .release_pmd = paravirt_nop, 440 .release_pud = paravirt_nop, 441 442 .set_pte = native_set_pte, 443 .set_pte_at = native_set_pte_at, 444 .set_pmd = native_set_pmd, 445 .set_pmd_at = native_set_pmd_at, 446 .pte_update = paravirt_nop, 447 .pte_update_defer = paravirt_nop, 448 .pmd_update = paravirt_nop, 449 .pmd_update_defer = paravirt_nop, 450 451 .ptep_modify_prot_start = __ptep_modify_prot_start, 452 .ptep_modify_prot_commit = __ptep_modify_prot_commit, 453 454#if CONFIG_PGTABLE_LEVELS >= 3 455#ifdef CONFIG_X86_PAE 456 .set_pte_atomic = native_set_pte_atomic, 457 .pte_clear = native_pte_clear, 458 .pmd_clear = native_pmd_clear, 459#endif 460 .set_pud = native_set_pud, 461 462 .pmd_val = PTE_IDENT, 463 .make_pmd = PTE_IDENT, 464 465#if CONFIG_PGTABLE_LEVELS == 4 466 .pud_val = PTE_IDENT, 467 .make_pud = PTE_IDENT, 468 469 .set_pgd = native_set_pgd, 470#endif 471#endif /* CONFIG_PGTABLE_LEVELS >= 3 */ 472 473 .pte_val = PTE_IDENT, 474 .pgd_val = PTE_IDENT, 475 476 .make_pte = PTE_IDENT, 477 .make_pgd = PTE_IDENT, 478 479 .dup_mmap = paravirt_nop, 480 .exit_mmap = paravirt_nop, 481 .activate_mm = paravirt_nop, 482 483 .lazy_mode = { 484 .enter = paravirt_nop, 485 .leave = paravirt_nop, 486 .flush = paravirt_nop, 487 }, 488 489 .set_fixmap = native_set_fixmap, 490}; 491 492EXPORT_SYMBOL_GPL(pv_time_ops); 493EXPORT_SYMBOL (pv_cpu_ops); 494EXPORT_SYMBOL (pv_mmu_ops); 495EXPORT_SYMBOL_GPL(pv_apic_ops); 496EXPORT_SYMBOL_GPL(pv_info); 497EXPORT_SYMBOL (pv_irq_ops); 498