1/* 2 * This file contains ioremap and related functions for 64-bit machines. 3 * 4 * Derived from arch/ppc64/mm/init.c 5 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) 6 * 7 * Modifications by Paul Mackerras (PowerMac) (paulus@samba.org) 8 * and Cort Dougan (PReP) (cort@cs.nmt.edu) 9 * Copyright (C) 1996 Paul Mackerras 10 * 11 * Derived from "arch/i386/mm/init.c" 12 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds 13 * 14 * Dave Engebretsen <engebret@us.ibm.com> 15 * Rework for PPC64 port. 16 * 17 * This program is free software; you can redistribute it and/or 18 * modify it under the terms of the GNU General Public License 19 * as published by the Free Software Foundation; either version 20 * 2 of the License, or (at your option) any later version. 21 * 22 */ 23 24#include <linux/signal.h> 25#include <linux/sched.h> 26#include <linux/kernel.h> 27#include <linux/errno.h> 28#include <linux/string.h> 29#include <linux/export.h> 30#include <linux/types.h> 31#include <linux/mman.h> 32#include <linux/mm.h> 33#include <linux/swap.h> 34#include <linux/stddef.h> 35#include <linux/vmalloc.h> 36#include <linux/bootmem.h> 37#include <linux/memblock.h> 38#include <linux/slab.h> 39 40#include <asm/pgalloc.h> 41#include <asm/page.h> 42#include <asm/prom.h> 43#include <asm/io.h> 44#include <asm/mmu_context.h> 45#include <asm/pgtable.h> 46#include <asm/mmu.h> 47#include <asm/smp.h> 48#include <asm/machdep.h> 49#include <asm/tlb.h> 50#include <asm/processor.h> 51#include <asm/cputable.h> 52#include <asm/sections.h> 53#include <asm/firmware.h> 54 55#include "mmu_decl.h" 56 57#define CREATE_TRACE_POINTS 58#include <trace/events/thp.h> 59 60/* Some sanity checking */ 61#if TASK_SIZE_USER64 > PGTABLE_RANGE 62#error TASK_SIZE_USER64 exceeds pagetable range 63#endif 64 65#ifdef CONFIG_PPC_STD_MMU_64 66#if TASK_SIZE_USER64 > (1UL << (ESID_BITS + SID_SHIFT)) 67#error TASK_SIZE_USER64 exceeds user VSID range 68#endif 69#endif 70 71unsigned long ioremap_bot = IOREMAP_BASE; 72 73#ifdef CONFIG_PPC_MMU_NOHASH 74static __ref void *early_alloc_pgtable(unsigned long size) 75{ 76 void *pt; 77 78 if (init_bootmem_done) 79 pt = __alloc_bootmem(size, size, __pa(MAX_DMA_ADDRESS)); 80 else 81 pt = __va(memblock_alloc_base(size, size, 82 __pa(MAX_DMA_ADDRESS))); 83 memset(pt, 0, size); 84 85 return pt; 86} 87#endif /* CONFIG_PPC_MMU_NOHASH */ 88 89/* 90 * map_kernel_page currently only called by __ioremap 91 * map_kernel_page adds an entry to the ioremap page table 92 * and adds an entry to the HPT, possibly bolting it 93 */ 94int map_kernel_page(unsigned long ea, unsigned long pa, int flags) 95{ 96 pgd_t *pgdp; 97 pud_t *pudp; 98 pmd_t *pmdp; 99 pte_t *ptep; 100 101 if (slab_is_available()) { 102 pgdp = pgd_offset_k(ea); 103 pudp = pud_alloc(&init_mm, pgdp, ea); 104 if (!pudp) 105 return -ENOMEM; 106 pmdp = pmd_alloc(&init_mm, pudp, ea); 107 if (!pmdp) 108 return -ENOMEM; 109 ptep = pte_alloc_kernel(pmdp, ea); 110 if (!ptep) 111 return -ENOMEM; 112 set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT, 113 __pgprot(flags))); 114 } else { 115#ifdef CONFIG_PPC_MMU_NOHASH 116 /* Warning ! This will blow up if bootmem is not initialized 117 * which our ppc64 code is keen to do that, we'll need to 118 * fix it and/or be more careful 119 */ 120 pgdp = pgd_offset_k(ea); 121#ifdef PUD_TABLE_SIZE 122 if (pgd_none(*pgdp)) { 123 pudp = early_alloc_pgtable(PUD_TABLE_SIZE); 124 BUG_ON(pudp == NULL); 125 pgd_populate(&init_mm, pgdp, pudp); 126 } 127#endif /* PUD_TABLE_SIZE */ 128 pudp = pud_offset(pgdp, ea); 129 if (pud_none(*pudp)) { 130 pmdp = early_alloc_pgtable(PMD_TABLE_SIZE); 131 BUG_ON(pmdp == NULL); 132 pud_populate(&init_mm, pudp, pmdp); 133 } 134 pmdp = pmd_offset(pudp, ea); 135 if (!pmd_present(*pmdp)) { 136 ptep = early_alloc_pgtable(PAGE_SIZE); 137 BUG_ON(ptep == NULL); 138 pmd_populate_kernel(&init_mm, pmdp, ptep); 139 } 140 ptep = pte_offset_kernel(pmdp, ea); 141 set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT, 142 __pgprot(flags))); 143#else /* CONFIG_PPC_MMU_NOHASH */ 144 /* 145 * If the mm subsystem is not fully up, we cannot create a 146 * linux page table entry for this mapping. Simply bolt an 147 * entry in the hardware page table. 148 * 149 */ 150 if (htab_bolt_mapping(ea, ea + PAGE_SIZE, pa, flags, 151 mmu_io_psize, mmu_kernel_ssize)) { 152 printk(KERN_ERR "Failed to do bolted mapping IO " 153 "memory at %016lx !\n", pa); 154 return -ENOMEM; 155 } 156#endif /* !CONFIG_PPC_MMU_NOHASH */ 157 } 158 159#ifdef CONFIG_PPC_BOOK3E_64 160 /* 161 * With hardware tablewalk, a sync is needed to ensure that 162 * subsequent accesses see the PTE we just wrote. Unlike userspace 163 * mappings, we can't tolerate spurious faults, so make sure 164 * the new PTE will be seen the first time. 165 */ 166 mb(); 167#else 168 smp_wmb(); 169#endif 170 return 0; 171} 172 173 174/** 175 * __ioremap_at - Low level function to establish the page tables 176 * for an IO mapping 177 */ 178void __iomem * __ioremap_at(phys_addr_t pa, void *ea, unsigned long size, 179 unsigned long flags) 180{ 181 unsigned long i; 182 183 /* Make sure we have the base flags */ 184 if ((flags & _PAGE_PRESENT) == 0) 185 flags |= pgprot_val(PAGE_KERNEL); 186 187 /* Non-cacheable page cannot be coherent */ 188 if (flags & _PAGE_NO_CACHE) 189 flags &= ~_PAGE_COHERENT; 190 191 /* We don't support the 4K PFN hack with ioremap */ 192 if (flags & _PAGE_4K_PFN) 193 return NULL; 194 195 WARN_ON(pa & ~PAGE_MASK); 196 WARN_ON(((unsigned long)ea) & ~PAGE_MASK); 197 WARN_ON(size & ~PAGE_MASK); 198 199 for (i = 0; i < size; i += PAGE_SIZE) 200 if (map_kernel_page((unsigned long)ea+i, pa+i, flags)) 201 return NULL; 202 203 return (void __iomem *)ea; 204} 205 206/** 207 * __iounmap_from - Low level function to tear down the page tables 208 * for an IO mapping. This is used for mappings that 209 * are manipulated manually, like partial unmapping of 210 * PCI IOs or ISA space. 211 */ 212void __iounmap_at(void *ea, unsigned long size) 213{ 214 WARN_ON(((unsigned long)ea) & ~PAGE_MASK); 215 WARN_ON(size & ~PAGE_MASK); 216 217 unmap_kernel_range((unsigned long)ea, size); 218} 219 220void __iomem * __ioremap_caller(phys_addr_t addr, unsigned long size, 221 unsigned long flags, void *caller) 222{ 223 phys_addr_t paligned; 224 void __iomem *ret; 225 226 /* 227 * Choose an address to map it to. 228 * Once the imalloc system is running, we use it. 229 * Before that, we map using addresses going 230 * up from ioremap_bot. imalloc will use 231 * the addresses from ioremap_bot through 232 * IMALLOC_END 233 * 234 */ 235 paligned = addr & PAGE_MASK; 236 size = PAGE_ALIGN(addr + size) - paligned; 237 238 if ((size == 0) || (paligned == 0)) 239 return NULL; 240 241 if (mem_init_done) { 242 struct vm_struct *area; 243 244 area = __get_vm_area_caller(size, VM_IOREMAP, 245 ioremap_bot, IOREMAP_END, 246 caller); 247 if (area == NULL) 248 return NULL; 249 250 area->phys_addr = paligned; 251 ret = __ioremap_at(paligned, area->addr, size, flags); 252 if (!ret) 253 vunmap(area->addr); 254 } else { 255 ret = __ioremap_at(paligned, (void *)ioremap_bot, size, flags); 256 if (ret) 257 ioremap_bot += size; 258 } 259 260 if (ret) 261 ret += addr & ~PAGE_MASK; 262 return ret; 263} 264 265void __iomem * __ioremap(phys_addr_t addr, unsigned long size, 266 unsigned long flags) 267{ 268 return __ioremap_caller(addr, size, flags, __builtin_return_address(0)); 269} 270 271void __iomem * ioremap(phys_addr_t addr, unsigned long size) 272{ 273 unsigned long flags = _PAGE_NO_CACHE | _PAGE_GUARDED; 274 void *caller = __builtin_return_address(0); 275 276 if (ppc_md.ioremap) 277 return ppc_md.ioremap(addr, size, flags, caller); 278 return __ioremap_caller(addr, size, flags, caller); 279} 280 281void __iomem * ioremap_wc(phys_addr_t addr, unsigned long size) 282{ 283 unsigned long flags = _PAGE_NO_CACHE; 284 void *caller = __builtin_return_address(0); 285 286 if (ppc_md.ioremap) 287 return ppc_md.ioremap(addr, size, flags, caller); 288 return __ioremap_caller(addr, size, flags, caller); 289} 290 291void __iomem * ioremap_prot(phys_addr_t addr, unsigned long size, 292 unsigned long flags) 293{ 294 void *caller = __builtin_return_address(0); 295 296 /* writeable implies dirty for kernel addresses */ 297 if (flags & _PAGE_RW) 298 flags |= _PAGE_DIRTY; 299 300 /* we don't want to let _PAGE_USER and _PAGE_EXEC leak out */ 301 flags &= ~(_PAGE_USER | _PAGE_EXEC); 302 303#ifdef _PAGE_BAP_SR 304 /* _PAGE_USER contains _PAGE_BAP_SR on BookE using the new PTE format 305 * which means that we just cleared supervisor access... oops ;-) This 306 * restores it 307 */ 308 flags |= _PAGE_BAP_SR; 309#endif 310 311 if (ppc_md.ioremap) 312 return ppc_md.ioremap(addr, size, flags, caller); 313 return __ioremap_caller(addr, size, flags, caller); 314} 315 316 317/* 318 * Unmap an IO region and remove it from imalloc'd list. 319 * Access to IO memory should be serialized by driver. 320 */ 321void __iounmap(volatile void __iomem *token) 322{ 323 void *addr; 324 325 if (!mem_init_done) 326 return; 327 328 addr = (void *) ((unsigned long __force) 329 PCI_FIX_ADDR(token) & PAGE_MASK); 330 if ((unsigned long)addr < ioremap_bot) { 331 printk(KERN_WARNING "Attempt to iounmap early bolted mapping" 332 " at 0x%p\n", addr); 333 return; 334 } 335 vunmap(addr); 336} 337 338void iounmap(volatile void __iomem *token) 339{ 340 if (ppc_md.iounmap) 341 ppc_md.iounmap(token); 342 else 343 __iounmap(token); 344} 345 346EXPORT_SYMBOL(ioremap); 347EXPORT_SYMBOL(ioremap_wc); 348EXPORT_SYMBOL(ioremap_prot); 349EXPORT_SYMBOL(__ioremap); 350EXPORT_SYMBOL(__ioremap_at); 351EXPORT_SYMBOL(iounmap); 352EXPORT_SYMBOL(__iounmap); 353EXPORT_SYMBOL(__iounmap_at); 354 355/* 356 * For hugepage we have pfn in the pmd, we use PTE_RPN_SHIFT bits for flags 357 * For PTE page, we have a PTE_FRAG_SIZE (4K) aligned virtual address. 358 */ 359struct page *pmd_page(pmd_t pmd) 360{ 361#ifdef CONFIG_TRANSPARENT_HUGEPAGE 362 if (pmd_trans_huge(pmd)) 363 return pfn_to_page(pmd_pfn(pmd)); 364#endif 365 return virt_to_page(pmd_page_vaddr(pmd)); 366} 367 368#ifdef CONFIG_PPC_64K_PAGES 369static pte_t *get_from_cache(struct mm_struct *mm) 370{ 371 void *pte_frag, *ret; 372 373 spin_lock(&mm->page_table_lock); 374 ret = mm->context.pte_frag; 375 if (ret) { 376 pte_frag = ret + PTE_FRAG_SIZE; 377 /* 378 * If we have taken up all the fragments mark PTE page NULL 379 */ 380 if (((unsigned long)pte_frag & ~PAGE_MASK) == 0) 381 pte_frag = NULL; 382 mm->context.pte_frag = pte_frag; 383 } 384 spin_unlock(&mm->page_table_lock); 385 return (pte_t *)ret; 386} 387 388static pte_t *__alloc_for_cache(struct mm_struct *mm, int kernel) 389{ 390 void *ret = NULL; 391 struct page *page = alloc_page(GFP_KERNEL | __GFP_NOTRACK | 392 __GFP_REPEAT | __GFP_ZERO); 393 if (!page) 394 return NULL; 395 if (!kernel && !pgtable_page_ctor(page)) { 396 __free_page(page); 397 return NULL; 398 } 399 400 ret = page_address(page); 401 spin_lock(&mm->page_table_lock); 402 /* 403 * If we find pgtable_page set, we return 404 * the allocated page with single fragement 405 * count. 406 */ 407 if (likely(!mm->context.pte_frag)) { 408 atomic_set(&page->_count, PTE_FRAG_NR); 409 mm->context.pte_frag = ret + PTE_FRAG_SIZE; 410 } 411 spin_unlock(&mm->page_table_lock); 412 413 return (pte_t *)ret; 414} 415 416pte_t *page_table_alloc(struct mm_struct *mm, unsigned long vmaddr, int kernel) 417{ 418 pte_t *pte; 419 420 pte = get_from_cache(mm); 421 if (pte) 422 return pte; 423 424 return __alloc_for_cache(mm, kernel); 425} 426 427void page_table_free(struct mm_struct *mm, unsigned long *table, int kernel) 428{ 429 struct page *page = virt_to_page(table); 430 if (put_page_testzero(page)) { 431 if (!kernel) 432 pgtable_page_dtor(page); 433 free_hot_cold_page(page, 0); 434 } 435} 436 437#ifdef CONFIG_SMP 438static void page_table_free_rcu(void *table) 439{ 440 struct page *page = virt_to_page(table); 441 if (put_page_testzero(page)) { 442 pgtable_page_dtor(page); 443 free_hot_cold_page(page, 0); 444 } 445} 446 447void pgtable_free_tlb(struct mmu_gather *tlb, void *table, int shift) 448{ 449 unsigned long pgf = (unsigned long)table; 450 451 BUG_ON(shift > MAX_PGTABLE_INDEX_SIZE); 452 pgf |= shift; 453 tlb_remove_table(tlb, (void *)pgf); 454} 455 456void __tlb_remove_table(void *_table) 457{ 458 void *table = (void *)((unsigned long)_table & ~MAX_PGTABLE_INDEX_SIZE); 459 unsigned shift = (unsigned long)_table & MAX_PGTABLE_INDEX_SIZE; 460 461 if (!shift) 462 /* PTE page needs special handling */ 463 page_table_free_rcu(table); 464 else { 465 BUG_ON(shift > MAX_PGTABLE_INDEX_SIZE); 466 kmem_cache_free(PGT_CACHE(shift), table); 467 } 468} 469#else 470void pgtable_free_tlb(struct mmu_gather *tlb, void *table, int shift) 471{ 472 if (!shift) { 473 /* PTE page needs special handling */ 474 struct page *page = virt_to_page(table); 475 if (put_page_testzero(page)) { 476 pgtable_page_dtor(page); 477 free_hot_cold_page(page, 0); 478 } 479 } else { 480 BUG_ON(shift > MAX_PGTABLE_INDEX_SIZE); 481 kmem_cache_free(PGT_CACHE(shift), table); 482 } 483} 484#endif 485#endif /* CONFIG_PPC_64K_PAGES */ 486 487#ifdef CONFIG_TRANSPARENT_HUGEPAGE 488 489/* 490 * This is called when relaxing access to a hugepage. It's also called in the page 491 * fault path when we don't hit any of the major fault cases, ie, a minor 492 * update of _PAGE_ACCESSED, _PAGE_DIRTY, etc... The generic code will have 493 * handled those two for us, we additionally deal with missing execute 494 * permission here on some processors 495 */ 496int pmdp_set_access_flags(struct vm_area_struct *vma, unsigned long address, 497 pmd_t *pmdp, pmd_t entry, int dirty) 498{ 499 int changed; 500#ifdef CONFIG_DEBUG_VM 501 WARN_ON(!pmd_trans_huge(*pmdp)); 502 assert_spin_locked(&vma->vm_mm->page_table_lock); 503#endif 504 changed = !pmd_same(*(pmdp), entry); 505 if (changed) { 506 __ptep_set_access_flags(pmdp_ptep(pmdp), pmd_pte(entry)); 507 /* 508 * Since we are not supporting SW TLB systems, we don't 509 * have any thing similar to flush_tlb_page_nohash() 510 */ 511 } 512 return changed; 513} 514 515unsigned long pmd_hugepage_update(struct mm_struct *mm, unsigned long addr, 516 pmd_t *pmdp, unsigned long clr, 517 unsigned long set) 518{ 519 520 unsigned long old, tmp; 521 522#ifdef CONFIG_DEBUG_VM 523 WARN_ON(!pmd_trans_huge(*pmdp)); 524 assert_spin_locked(&mm->page_table_lock); 525#endif 526 527#ifdef PTE_ATOMIC_UPDATES 528 __asm__ __volatile__( 529 "1: ldarx %0,0,%3\n\ 530 andi. %1,%0,%6\n\ 531 bne- 1b \n\ 532 andc %1,%0,%4 \n\ 533 or %1,%1,%7\n\ 534 stdcx. %1,0,%3 \n\ 535 bne- 1b" 536 : "=&r" (old), "=&r" (tmp), "=m" (*pmdp) 537 : "r" (pmdp), "r" (clr), "m" (*pmdp), "i" (_PAGE_BUSY), "r" (set) 538 : "cc" ); 539#else 540 old = pmd_val(*pmdp); 541 *pmdp = __pmd((old & ~clr) | set); 542#endif 543 trace_hugepage_update(addr, old, clr, set); 544 if (old & _PAGE_HASHPTE) 545 hpte_do_hugepage_flush(mm, addr, pmdp, old); 546 return old; 547} 548 549pmd_t pmdp_clear_flush(struct vm_area_struct *vma, unsigned long address, 550 pmd_t *pmdp) 551{ 552 pmd_t pmd; 553 554 VM_BUG_ON(address & ~HPAGE_PMD_MASK); 555 if (pmd_trans_huge(*pmdp)) { 556 pmd = pmdp_get_and_clear(vma->vm_mm, address, pmdp); 557 } else { 558 /* 559 * khugepaged calls this for normal pmd 560 */ 561 pmd = *pmdp; 562 pmd_clear(pmdp); 563 /* 564 * Wait for all pending hash_page to finish. This is needed 565 * in case of subpage collapse. When we collapse normal pages 566 * to hugepage, we first clear the pmd, then invalidate all 567 * the PTE entries. The assumption here is that any low level 568 * page fault will see a none pmd and take the slow path that 569 * will wait on mmap_sem. But we could very well be in a 570 * hash_page with local ptep pointer value. Such a hash page 571 * can result in adding new HPTE entries for normal subpages. 572 * That means we could be modifying the page content as we 573 * copy them to a huge page. So wait for parallel hash_page 574 * to finish before invalidating HPTE entries. We can do this 575 * by sending an IPI to all the cpus and executing a dummy 576 * function there. 577 */ 578 kick_all_cpus_sync(); 579 /* 580 * Now invalidate the hpte entries in the range 581 * covered by pmd. This make sure we take a 582 * fault and will find the pmd as none, which will 583 * result in a major fault which takes mmap_sem and 584 * hence wait for collapse to complete. Without this 585 * the __collapse_huge_page_copy can result in copying 586 * the old content. 587 */ 588 flush_tlb_pmd_range(vma->vm_mm, &pmd, address); 589 } 590 return pmd; 591} 592 593int pmdp_test_and_clear_young(struct vm_area_struct *vma, 594 unsigned long address, pmd_t *pmdp) 595{ 596 return __pmdp_test_and_clear_young(vma->vm_mm, address, pmdp); 597} 598 599/* 600 * We currently remove entries from the hashtable regardless of whether 601 * the entry was young or dirty. The generic routines only flush if the 602 * entry was young or dirty which is not good enough. 603 * 604 * We should be more intelligent about this but for the moment we override 605 * these functions and force a tlb flush unconditionally 606 */ 607int pmdp_clear_flush_young(struct vm_area_struct *vma, 608 unsigned long address, pmd_t *pmdp) 609{ 610 return __pmdp_test_and_clear_young(vma->vm_mm, address, pmdp); 611} 612 613/* 614 * We mark the pmd splitting and invalidate all the hpte 615 * entries for this hugepage. 616 */ 617void pmdp_splitting_flush(struct vm_area_struct *vma, 618 unsigned long address, pmd_t *pmdp) 619{ 620 unsigned long old, tmp; 621 622 VM_BUG_ON(address & ~HPAGE_PMD_MASK); 623 624#ifdef CONFIG_DEBUG_VM 625 WARN_ON(!pmd_trans_huge(*pmdp)); 626 assert_spin_locked(&vma->vm_mm->page_table_lock); 627#endif 628 629#ifdef PTE_ATOMIC_UPDATES 630 631 __asm__ __volatile__( 632 "1: ldarx %0,0,%3\n\ 633 andi. %1,%0,%6\n\ 634 bne- 1b \n\ 635 ori %1,%0,%4 \n\ 636 stdcx. %1,0,%3 \n\ 637 bne- 1b" 638 : "=&r" (old), "=&r" (tmp), "=m" (*pmdp) 639 : "r" (pmdp), "i" (_PAGE_SPLITTING), "m" (*pmdp), "i" (_PAGE_BUSY) 640 : "cc" ); 641#else 642 old = pmd_val(*pmdp); 643 *pmdp = __pmd(old | _PAGE_SPLITTING); 644#endif 645 /* 646 * If we didn't had the splitting flag set, go and flush the 647 * HPTE entries. 648 */ 649 trace_hugepage_splitting(address, old); 650 if (!(old & _PAGE_SPLITTING)) { 651 /* We need to flush the hpte */ 652 if (old & _PAGE_HASHPTE) 653 hpte_do_hugepage_flush(vma->vm_mm, address, pmdp, old); 654 } 655 /* 656 * This ensures that generic code that rely on IRQ disabling 657 * to prevent a parallel THP split work as expected. 658 */ 659 kick_all_cpus_sync(); 660} 661 662/* 663 * We want to put the pgtable in pmd and use pgtable for tracking 664 * the base page size hptes 665 */ 666void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp, 667 pgtable_t pgtable) 668{ 669 pgtable_t *pgtable_slot; 670 assert_spin_locked(&mm->page_table_lock); 671 /* 672 * we store the pgtable in the second half of PMD 673 */ 674 pgtable_slot = (pgtable_t *)pmdp + PTRS_PER_PMD; 675 *pgtable_slot = pgtable; 676 /* 677 * expose the deposited pgtable to other cpus. 678 * before we set the hugepage PTE at pmd level 679 * hash fault code looks at the deposted pgtable 680 * to store hash index values. 681 */ 682 smp_wmb(); 683} 684 685pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp) 686{ 687 pgtable_t pgtable; 688 pgtable_t *pgtable_slot; 689 690 assert_spin_locked(&mm->page_table_lock); 691 pgtable_slot = (pgtable_t *)pmdp + PTRS_PER_PMD; 692 pgtable = *pgtable_slot; 693 /* 694 * Once we withdraw, mark the entry NULL. 695 */ 696 *pgtable_slot = NULL; 697 /* 698 * We store HPTE information in the deposited PTE fragment. 699 * zero out the content on withdraw. 700 */ 701 memset(pgtable, 0, PTE_FRAG_SIZE); 702 return pgtable; 703} 704 705/* 706 * set a new huge pmd. We should not be called for updating 707 * an existing pmd entry. That should go via pmd_hugepage_update. 708 */ 709void set_pmd_at(struct mm_struct *mm, unsigned long addr, 710 pmd_t *pmdp, pmd_t pmd) 711{ 712#ifdef CONFIG_DEBUG_VM 713 WARN_ON(pmd_val(*pmdp) & _PAGE_PRESENT); 714 assert_spin_locked(&mm->page_table_lock); 715 WARN_ON(!pmd_trans_huge(pmd)); 716#endif 717 trace_hugepage_set_pmd(addr, pmd); 718 return set_pte_at(mm, addr, pmdp_ptep(pmdp), pmd_pte(pmd)); 719} 720 721void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address, 722 pmd_t *pmdp) 723{ 724 pmd_hugepage_update(vma->vm_mm, address, pmdp, _PAGE_PRESENT, 0); 725} 726 727/* 728 * A linux hugepage PMD was changed and the corresponding hash table entries 729 * neesd to be flushed. 730 */ 731void hpte_do_hugepage_flush(struct mm_struct *mm, unsigned long addr, 732 pmd_t *pmdp, unsigned long old_pmd) 733{ 734 int ssize, i; 735 unsigned long s_addr; 736 int max_hpte_count; 737 unsigned int psize, valid; 738 unsigned char *hpte_slot_array; 739 unsigned long hidx, vpn, vsid, hash, shift, slot; 740 741 /* 742 * Flush all the hptes mapping this hugepage 743 */ 744 s_addr = addr & HPAGE_PMD_MASK; 745 hpte_slot_array = get_hpte_slot_array(pmdp); 746 /* 747 * IF we try to do a HUGE PTE update after a withdraw is done. 748 * we will find the below NULL. This happens when we do 749 * split_huge_page_pmd 750 */ 751 if (!hpte_slot_array) 752 return; 753 754 /* get the base page size,vsid and segment size */ 755#ifdef CONFIG_DEBUG_VM 756 psize = get_slice_psize(mm, s_addr); 757 BUG_ON(psize == MMU_PAGE_16M); 758#endif 759 if (old_pmd & _PAGE_COMBO) 760 psize = MMU_PAGE_4K; 761 else 762 psize = MMU_PAGE_64K; 763 764 if (!is_kernel_addr(s_addr)) { 765 ssize = user_segment_size(s_addr); 766 vsid = get_vsid(mm->context.id, s_addr, ssize); 767 WARN_ON(vsid == 0); 768 } else { 769 vsid = get_kernel_vsid(s_addr, mmu_kernel_ssize); 770 ssize = mmu_kernel_ssize; 771 } 772 773 if (ppc_md.hugepage_invalidate) 774 return ppc_md.hugepage_invalidate(vsid, s_addr, 775 hpte_slot_array, 776 psize, ssize); 777 /* 778 * No bluk hpte removal support, invalidate each entry 779 */ 780 shift = mmu_psize_defs[psize].shift; 781 max_hpte_count = HPAGE_PMD_SIZE >> shift; 782 for (i = 0; i < max_hpte_count; i++) { 783 /* 784 * 8 bits per each hpte entries 785 * 000| [ secondary group (one bit) | hidx (3 bits) | valid bit] 786 */ 787 valid = hpte_valid(hpte_slot_array, i); 788 if (!valid) 789 continue; 790 hidx = hpte_hash_index(hpte_slot_array, i); 791 792 /* get the vpn */ 793 addr = s_addr + (i * (1ul << shift)); 794 vpn = hpt_vpn(addr, vsid, ssize); 795 hash = hpt_hash(vpn, shift, ssize); 796 if (hidx & _PTEIDX_SECONDARY) 797 hash = ~hash; 798 799 slot = (hash & htab_hash_mask) * HPTES_PER_GROUP; 800 slot += hidx & _PTEIDX_GROUP_IX; 801 ppc_md.hpte_invalidate(slot, vpn, psize, 802 MMU_PAGE_16M, ssize, 0); 803 } 804} 805 806static pmd_t pmd_set_protbits(pmd_t pmd, pgprot_t pgprot) 807{ 808 pmd_val(pmd) |= pgprot_val(pgprot); 809 return pmd; 810} 811 812pmd_t pfn_pmd(unsigned long pfn, pgprot_t pgprot) 813{ 814 pmd_t pmd; 815 /* 816 * For a valid pte, we would have _PAGE_PRESENT or _PAGE_FILE always 817 * set. We use this to check THP page at pmd level. 818 * leaf pte for huge page, bottom two bits != 00 819 */ 820 pmd_val(pmd) = pfn << PTE_RPN_SHIFT; 821 pmd_val(pmd) |= _PAGE_THP_HUGE; 822 pmd = pmd_set_protbits(pmd, pgprot); 823 return pmd; 824} 825 826pmd_t mk_pmd(struct page *page, pgprot_t pgprot) 827{ 828 return pfn_pmd(page_to_pfn(page), pgprot); 829} 830 831pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot) 832{ 833 834 pmd_val(pmd) &= _HPAGE_CHG_MASK; 835 pmd = pmd_set_protbits(pmd, newprot); 836 return pmd; 837} 838 839/* 840 * This is called at the end of handling a user page fault, when the 841 * fault has been handled by updating a HUGE PMD entry in the linux page tables. 842 * We use it to preload an HPTE into the hash table corresponding to 843 * the updated linux HUGE PMD entry. 844 */ 845void update_mmu_cache_pmd(struct vm_area_struct *vma, unsigned long addr, 846 pmd_t *pmd) 847{ 848 return; 849} 850 851pmd_t pmdp_get_and_clear(struct mm_struct *mm, 852 unsigned long addr, pmd_t *pmdp) 853{ 854 pmd_t old_pmd; 855 pgtable_t pgtable; 856 unsigned long old; 857 pgtable_t *pgtable_slot; 858 859 old = pmd_hugepage_update(mm, addr, pmdp, ~0UL, 0); 860 old_pmd = __pmd(old); 861 /* 862 * We have pmd == none and we are holding page_table_lock. 863 * So we can safely go and clear the pgtable hash 864 * index info. 865 */ 866 pgtable_slot = (pgtable_t *)pmdp + PTRS_PER_PMD; 867 pgtable = *pgtable_slot; 868 /* 869 * Let's zero out old valid and hash index details 870 * hash fault look at them. 871 */ 872 memset(pgtable, 0, PTE_FRAG_SIZE); 873 return old_pmd; 874} 875 876int has_transparent_hugepage(void) 877{ 878 if (!mmu_has_feature(MMU_FTR_16M_PAGE)) 879 return 0; 880 /* 881 * We support THP only if PMD_SIZE is 16MB. 882 */ 883 if (mmu_psize_defs[MMU_PAGE_16M].shift != PMD_SHIFT) 884 return 0; 885 /* 886 * We need to make sure that we support 16MB hugepage in a segement 887 * with base page size 64K or 4K. We only enable THP with a PAGE_SIZE 888 * of 64K. 889 */ 890 /* 891 * If we have 64K HPTE, we will be using that by default 892 */ 893 if (mmu_psize_defs[MMU_PAGE_64K].shift && 894 (mmu_psize_defs[MMU_PAGE_64K].penc[MMU_PAGE_16M] == -1)) 895 return 0; 896 /* 897 * Ok we only have 4K HPTE 898 */ 899 if (mmu_psize_defs[MMU_PAGE_4K].penc[MMU_PAGE_16M] == -1) 900 return 0; 901 902 return 1; 903} 904#endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 905