/* * Copyright 2002 Andi Kleen, SuSE Labs. * Thanks to Ben LaHaise for precious feedback. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * The current flushing context - we pass it instead of 5 arguments: */ struct cpa_data { unsigned long *vaddr; pgd_t *pgd; pgprot_t mask_set; pgprot_t mask_clr; int numpages; int flags; unsigned long pfn; unsigned force_split : 1; int curpage; struct page **pages; }; /* * Serialize cpa() (for !DEBUG_PAGEALLOC which uses large identity mappings) * using cpa_lock. So that we don't allow any other cpu, with stale large tlb * entries change the page attribute in parallel to some other cpu * splitting a large page entry along with changing the attribute. */ static DEFINE_SPINLOCK(cpa_lock); #define CPA_FLUSHTLB 1 #define CPA_ARRAY 2 #define CPA_PAGES_ARRAY 4 #ifdef CONFIG_PROC_FS static unsigned long direct_pages_count[PG_LEVEL_NUM]; void update_page_count(int level, unsigned long pages) { /* Protect against CPA */ spin_lock(&pgd_lock); direct_pages_count[level] += pages; spin_unlock(&pgd_lock); } static void split_page_count(int level) { direct_pages_count[level]--; direct_pages_count[level - 1] += PTRS_PER_PTE; } void arch_report_meminfo(struct seq_file *m) { seq_printf(m, "DirectMap4k: %8lu kB\n", direct_pages_count[PG_LEVEL_4K] << 2); #if defined(CONFIG_X86_64) || defined(CONFIG_X86_PAE) seq_printf(m, "DirectMap2M: %8lu kB\n", direct_pages_count[PG_LEVEL_2M] << 11); #else seq_printf(m, "DirectMap4M: %8lu kB\n", direct_pages_count[PG_LEVEL_2M] << 12); #endif #ifdef CONFIG_X86_64 if (direct_gbpages) seq_printf(m, "DirectMap1G: %8lu kB\n", direct_pages_count[PG_LEVEL_1G] << 20); #endif } #else static inline void split_page_count(int level) { } #endif #ifdef CONFIG_X86_64 static inline unsigned long highmap_start_pfn(void) { return __pa_symbol(_text) >> PAGE_SHIFT; } static inline unsigned long highmap_end_pfn(void) { return __pa_symbol(roundup(_brk_end, PMD_SIZE)) >> PAGE_SHIFT; } #endif #ifdef CONFIG_DEBUG_PAGEALLOC # define debug_pagealloc 1 #else # define debug_pagealloc 0 #endif static inline int within(unsigned long addr, unsigned long start, unsigned long end) { return addr >= start && addr < end; } /* * Flushing functions */ /** * clflush_cache_range - flush a cache range with clflush * @vaddr: virtual start address * @size: number of bytes to flush * * clflush is an unordered instruction which needs fencing with mfence * to avoid ordering issues. */ void clflush_cache_range(void *vaddr, unsigned int size) { void *vend = vaddr + size - 1; mb(); for (; vaddr < vend; vaddr += boot_cpu_data.x86_clflush_size) clflush(vaddr); /* * Flush any possible final partial cacheline: */ clflush(vend); mb(); } EXPORT_SYMBOL_GPL(clflush_cache_range); static void __cpa_flush_all(void *arg) { unsigned long cache = (unsigned long)arg; /* * Flush all to work around Errata in early athlons regarding * large page flushing. */ __flush_tlb_all(); if (cache && boot_cpu_data.x86 >= 4) wbinvd(); } static void cpa_flush_all(unsigned long cache) { BUG_ON(irqs_disabled()); on_each_cpu(__cpa_flush_all, (void *) cache, 1); } static void __cpa_flush_range(void *arg) { /* * We could optimize that further and do individual per page * tlb invalidates for a low number of pages. Caveat: we must * flush the high aliases on 64bit as well. */ __flush_tlb_all(); } static void cpa_flush_range(unsigned long start, int numpages, int cache) { unsigned int i, level; unsigned long addr; BUG_ON(irqs_disabled()); WARN_ON(PAGE_ALIGN(start) != start); on_each_cpu(__cpa_flush_range, NULL, 1); if (!cache) return; /* * We only need to flush on one CPU, * clflush is a MESI-coherent instruction that * will cause all other CPUs to flush the same * cachelines: */ for (i = 0, addr = start; i < numpages; i++, addr += PAGE_SIZE) { pte_t *pte = lookup_address(addr, &level); /* * Only flush present addresses: */ if (pte && (pte_val(*pte) & _PAGE_PRESENT)) clflush_cache_range((void *) addr, PAGE_SIZE); } } static void cpa_flush_array(unsigned long *start, int numpages, int cache, int in_flags, struct page **pages) { unsigned int i, level; unsigned long do_wbinvd = cache && numpages >= 1024; /* 4M threshold */ BUG_ON(irqs_disabled()); on_each_cpu(__cpa_flush_all, (void *) do_wbinvd, 1); if (!cache || do_wbinvd) return; /* * We only need to flush on one CPU, * clflush is a MESI-coherent instruction that * will cause all other CPUs to flush the same * cachelines: */ for (i = 0; i < numpages; i++) { unsigned long addr; pte_t *pte; if (in_flags & CPA_PAGES_ARRAY) addr = (unsigned long)page_address(pages[i]); else addr = start[i]; pte = lookup_address(addr, &level); /* * Only flush present addresses: */ if (pte && (pte_val(*pte) & _PAGE_PRESENT)) clflush_cache_range((void *)addr, PAGE_SIZE); } } /* * Certain areas of memory on x86 require very specific protection flags, * for example the BIOS area or kernel text. Callers don't always get this * right (again, ioremap() on BIOS memory is not uncommon) so this function * checks and fixes these known static required protection bits. */ static inline pgprot_t static_protections(pgprot_t prot, unsigned long address, unsigned long pfn) { pgprot_t forbidden = __pgprot(0); /* * The BIOS area between 640k and 1Mb needs to be executable for * PCI BIOS based config access (CONFIG_PCI_GOBIOS) support. */ #ifdef CONFIG_PCI_BIOS if (pcibios_enabled && within(pfn, BIOS_BEGIN >> PAGE_SHIFT, BIOS_END >> PAGE_SHIFT)) pgprot_val(forbidden) |= _PAGE_NX; #endif /* * The kernel text needs to be executable for obvious reasons * Does not cover __inittext since that is gone later on. On * 64bit we do not enforce !NX on the low mapping */ if (within(address, (unsigned long)_text, (unsigned long)_etext)) pgprot_val(forbidden) |= _PAGE_NX; /* * The .rodata section needs to be read-only. Using the pfn * catches all aliases. */ if (within(pfn, __pa_symbol(__start_rodata) >> PAGE_SHIFT, __pa_symbol(__end_rodata) >> PAGE_SHIFT)) pgprot_val(forbidden) |= _PAGE_RW; #if defined(CONFIG_X86_64) && defined(CONFIG_DEBUG_RODATA) /* * Once the kernel maps the text as RO (kernel_set_to_readonly is set), * kernel text mappings for the large page aligned text, rodata sections * will be always read-only. For the kernel identity mappings covering * the holes caused by this alignment can be anything that user asks. * * This will preserve the large page mappings for kernel text/data * at no extra cost. */ if (kernel_set_to_readonly && within(address, (unsigned long)_text, (unsigned long)__end_rodata_hpage_align)) { unsigned int level; /* * Don't enforce the !RW mapping for the kernel text mapping, * if the current mapping is already using small page mapping. * No need to work hard to preserve large page mappings in this * case. * * This also fixes the Linux Xen paravirt guest boot failure * (because of unexpected read-only mappings for kernel identity * mappings). In this paravirt guest case, the kernel text * mapping and the kernel identity mapping share the same * page-table pages. Thus we can't really use different * protections for the kernel text and identity mappings. Also, * these shared mappings are made of small page mappings. * Thus this don't enforce !RW mapping for small page kernel * text mapping logic will help Linux Xen parvirt guest boot * as well. */ if (lookup_address(address, &level) && (level != PG_LEVEL_4K)) pgprot_val(forbidden) |= _PAGE_RW; } #endif prot = __pgprot(pgprot_val(prot) & ~pgprot_val(forbidden)); return prot; } static pte_t *__lookup_address_in_pgd(pgd_t *pgd, unsigned long address, unsigned int *level) { pud_t *pud; pmd_t *pmd; *level = PG_LEVEL_NONE; if (pgd_none(*pgd)) return NULL; pud = pud_offset(pgd, address); if (pud_none(*pud)) return NULL; *level = PG_LEVEL_1G; if (pud_large(*pud) || !pud_present(*pud)) return (pte_t *)pud; pmd = pmd_offset(pud, address); if (pmd_none(*pmd)) return NULL; *level = PG_LEVEL_2M; if (pmd_large(*pmd) || !pmd_present(*pmd)) return (pte_t *)pmd; *level = PG_LEVEL_4K; return pte_offset_kernel(pmd, address); } /* * Lookup the page table entry for a virtual address. Return a pointer * to the entry and the level of the mapping. * * Note: We return pud and pmd either when the entry is marked large * or when the present bit is not set. Otherwise we would return a * pointer to a nonexisting mapping. */ pte_t *lookup_address(unsigned long address, unsigned int *level) { return __lookup_address_in_pgd(pgd_offset_k(address), address, level); } EXPORT_SYMBOL_GPL(lookup_address); static pte_t *_lookup_address_cpa(struct cpa_data *cpa, unsigned long address, unsigned int *level) { if (cpa->pgd) return __lookup_address_in_pgd(cpa->pgd + pgd_index(address), address, level); return lookup_address(address, level); } /* * This is necessary because __pa() does not work on some * kinds of memory, like vmalloc() or the alloc_remap() * areas on 32-bit NUMA systems. The percpu areas can * end up in this kind of memory, for instance. * * This could be optimized, but it is only intended to be * used at inititalization time, and keeping it * unoptimized should increase the testing coverage for * the more obscure platforms. */ phys_addr_t slow_virt_to_phys(void *__virt_addr) { unsigned long virt_addr = (unsigned long)__virt_addr; phys_addr_t phys_addr; unsigned long offset; enum pg_level level; unsigned long psize; unsigned long pmask; pte_t *pte; pte = lookup_address(virt_addr, &level); BUG_ON(!pte); psize = page_level_size(level); pmask = page_level_mask(level); offset = virt_addr & ~pmask; phys_addr = (phys_addr_t)pte_pfn(*pte) << PAGE_SHIFT; return (phys_addr | offset); } EXPORT_SYMBOL_GPL(slow_virt_to_phys); /* * Set the new pmd in all the pgds we know about: */ static void __set_pmd_pte(pte_t *kpte, unsigned long address, pte_t pte) { /* change init_mm */ set_pte_atomic(kpte, pte); #ifdef CONFIG_X86_32 if (!SHARED_KERNEL_PMD) { struct page *page; list_for_each_entry(page, &pgd_list, lru) { pgd_t *pgd; pud_t *pud; pmd_t *pmd; pgd = (pgd_t *)page_address(page) + pgd_index(address); pud = pud_offset(pgd, address); pmd = pmd_offset(pud, address); set_pte_atomic((pte_t *)pmd, pte); } } #endif } static int try_preserve_large_page(pte_t *kpte, unsigned long address, struct cpa_data *cpa) { unsigned long nextpage_addr, numpages, pmask, psize, addr, pfn; pte_t new_pte, old_pte, *tmp; pgprot_t old_prot, new_prot, req_prot; int i, do_split = 1; enum pg_level level; if (cpa->force_split) return 1; spin_lock(&pgd_lock); /* * Check for races, another CPU might have split this page * up already: */ tmp = _lookup_address_cpa(cpa, address, &level); if (tmp != kpte) goto out_unlock; switch (level) { case PG_LEVEL_2M: #ifdef CONFIG_X86_64 case PG_LEVEL_1G: #endif psize = page_level_size(level); pmask = page_level_mask(level); break; default: do_split = -EINVAL; goto out_unlock; } /* * Calculate the number of pages, which fit into this large * page starting at address: */ nextpage_addr = (address + psize) & pmask; numpages = (nextpage_addr - address) >> PAGE_SHIFT; if (numpages < cpa->numpages) cpa->numpages = numpages; /* * We are safe now. Check whether the new pgprot is the same: */ old_pte = *kpte; old_prot = req_prot = pte_pgprot(old_pte); pgprot_val(req_prot) &= ~pgprot_val(cpa->mask_clr); pgprot_val(req_prot) |= pgprot_val(cpa->mask_set); /* * Set the PSE and GLOBAL flags only if the PRESENT flag is * set otherwise pmd_present/pmd_huge will return true even on * a non present pmd. The canon_pgprot will clear _PAGE_GLOBAL * for the ancient hardware that doesn't support it. */ if (pgprot_val(req_prot) & _PAGE_PRESENT) pgprot_val(req_prot) |= _PAGE_PSE | _PAGE_GLOBAL; else pgprot_val(req_prot) &= ~(_PAGE_PSE | _PAGE_GLOBAL); req_prot = canon_pgprot(req_prot); /* * old_pte points to the large page base address. So we need * to add the offset of the virtual address: */ pfn = pte_pfn(old_pte) + ((address & (psize - 1)) >> PAGE_SHIFT); cpa->pfn = pfn; new_prot = static_protections(req_prot, address, pfn); /* * We need to check the full range, whether * static_protection() requires a different pgprot for one of * the pages in the range we try to preserve: */ addr = address & pmask; pfn = pte_pfn(old_pte); for (i = 0; i < (psize >> PAGE_SHIFT); i++, addr += PAGE_SIZE, pfn++) { pgprot_t chk_prot = static_protections(req_prot, addr, pfn); if (pgprot_val(chk_prot) != pgprot_val(new_prot)) goto out_unlock; } /* * If there are no changes, return. maxpages has been updated * above: */ if (pgprot_val(new_prot) == pgprot_val(old_prot)) { do_split = 0; goto out_unlock; } /* * We need to change the attributes. Check, whether we can * change the large page in one go. We request a split, when * the address is not aligned and the number of pages is * smaller than the number of pages in the large page. Note * that we limited the number of possible pages already to * the number of pages in the large page. */ if (address == (address & pmask) && cpa->numpages == (psize >> PAGE_SHIFT)) { /* * The address is aligned and the number of pages * covers the full page. */ new_pte = pfn_pte(pte_pfn(old_pte), new_prot); __set_pmd_pte(kpte, address, new_pte); cpa->flags |= CPA_FLUSHTLB; do_split = 0; } out_unlock: spin_unlock(&pgd_lock); return do_split; } static int __split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address, struct page *base) { pte_t *pbase = (pte_t *)page_address(base); unsigned long pfn, pfninc = 1; unsigned int i, level; pte_t *tmp; pgprot_t ref_prot; spin_lock(&pgd_lock); /* * Check for races, another CPU might have split this page * up for us already: */ tmp = _lookup_address_cpa(cpa, address, &level); if (tmp != kpte) { spin_unlock(&pgd_lock); return 1; } paravirt_alloc_pte(&init_mm, page_to_pfn(base)); ref_prot = pte_pgprot(pte_clrhuge(*kpte)); /* * If we ever want to utilize the PAT bit, we need to * update this function to make sure it's converted from * bit 12 to bit 7 when we cross from the 2MB level to * the 4K level: */ WARN_ON_ONCE(pgprot_val(ref_prot) & _PAGE_PAT_LARGE); #ifdef CONFIG_X86_64 if (level == PG_LEVEL_1G) { pfninc = PMD_PAGE_SIZE >> PAGE_SHIFT; /* * Set the PSE flags only if the PRESENT flag is set * otherwise pmd_present/pmd_huge will return true * even on a non present pmd. */ if (pgprot_val(ref_prot) & _PAGE_PRESENT) pgprot_val(ref_prot) |= _PAGE_PSE; else pgprot_val(ref_prot) &= ~_PAGE_PSE; } #endif /* * Set the GLOBAL flags only if the PRESENT flag is set * otherwise pmd/pte_present will return true even on a non * present pmd/pte. The canon_pgprot will clear _PAGE_GLOBAL * for the ancient hardware that doesn't support it. */ if (pgprot_val(ref_prot) & _PAGE_PRESENT) pgprot_val(ref_prot) |= _PAGE_GLOBAL; else pgprot_val(ref_prot) &= ~_PAGE_GLOBAL; /* * Get the target pfn from the original entry: */ pfn = pte_pfn(*kpte); for (i = 0; i < PTRS_PER_PTE; i++, pfn += pfninc) set_pte(&pbase[i], pfn_pte(pfn, canon_pgprot(ref_prot))); if (pfn_range_is_mapped(PFN_DOWN(__pa(address)), PFN_DOWN(__pa(address)) + 1)) split_page_count(level); /* * Install the new, split up pagetable. * * We use the standard kernel pagetable protections for the new * pagetable protections, the actual ptes set above control the * primary protection behavior: */ __set_pmd_pte(kpte, address, mk_pte(base, __pgprot(_KERNPG_TABLE))); /* * Intel Atom errata AAH41 workaround. * * The real fix should be in hw or in a microcode update, but * we also probabilistically try to reduce the window of having * a large TLB mixed with 4K TLBs while instruction fetches are * going on. */ __flush_tlb_all(); spin_unlock(&pgd_lock); return 0; } static int split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address) { struct page *base; if (!debug_pagealloc) spin_unlock(&cpa_lock); base = alloc_pages(GFP_KERNEL | __GFP_NOTRACK, 0); if (!debug_pagealloc) spin_lock(&cpa_lock); if (!base) return -ENOMEM; if (__split_large_page(cpa, kpte, address, base)) __free_page(base); return 0; } static bool try_to_free_pte_page(pte_t *pte) { int i; for (i = 0; i < PTRS_PER_PTE; i++) if (!pte_none(pte[i])) return false; free_page((unsigned long)pte); return true; } static bool try_to_free_pmd_page(pmd_t *pmd) { int i; for (i = 0; i < PTRS_PER_PMD; i++) if (!pmd_none(pmd[i])) return false; free_page((unsigned long)pmd); return true; } static bool try_to_free_pud_page(pud_t *pud) { int i; for (i = 0; i < PTRS_PER_PUD; i++) if (!pud_none(pud[i])) return false; free_page((unsigned long)pud); return true; } static bool unmap_pte_range(pmd_t *pmd, unsigned long start, unsigned long end) { pte_t *pte = pte_offset_kernel(pmd, start); while (start < end) { set_pte(pte, __pte(0)); start += PAGE_SIZE; pte++; } if (try_to_free_pte_page((pte_t *)pmd_page_vaddr(*pmd))) { pmd_clear(pmd); return true; } return false; } static void __unmap_pmd_range(pud_t *pud, pmd_t *pmd, unsigned long start, unsigned long end) { if (unmap_pte_range(pmd, start, end)) if (try_to_free_pmd_page((pmd_t *)pud_page_vaddr(*pud))) pud_clear(pud); } static void unmap_pmd_range(pud_t *pud, unsigned long start, unsigned long end) { pmd_t *pmd = pmd_offset(pud, start); /* * Not on a 2MB page boundary? */ if (start & (PMD_SIZE - 1)) { unsigned long next_page = (start + PMD_SIZE) & PMD_MASK; unsigned long pre_end = min_t(unsigned long, end, next_page); __unmap_pmd_range(pud, pmd, start, pre_end); start = pre_end; pmd++; } /* * Try to unmap in 2M chunks. */ while (end - start >= PMD_SIZE) { if (pmd_large(*pmd)) pmd_clear(pmd); else __unmap_pmd_range(pud, pmd, start, start + PMD_SIZE); start += PMD_SIZE; pmd++; } /* * 4K leftovers? */ if (start < end) return __unmap_pmd_range(pud, pmd, start, end); /* * Try again to free the PMD page if haven't succeeded above. */ if (!pud_none(*pud)) if (try_to_free_pmd_page((pmd_t *)pud_page_vaddr(*pud))) pud_clear(pud); } static void unmap_pud_range(pgd_t *pgd, unsigned long start, unsigned long end) { pud_t *pud = pud_offset(pgd, start); /* * Not on a GB page boundary? */ if (start & (PUD_SIZE - 1)) { unsigned long next_page = (start + PUD_SIZE) & PUD_MASK; unsigned long pre_end = min_t(unsigned long, end, next_page); unmap_pmd_range(pud, start, pre_end); start = pre_end; pud++; } /* * Try to unmap in 1G chunks? */ while (end - start >= PUD_SIZE) { if (pud_large(*pud)) pud_clear(pud); else unmap_pmd_range(pud, start, start + PUD_SIZE); start += PUD_SIZE; pud++; } /* * 2M leftovers? */ if (start < end) unmap_pmd_range(pud, start, end); /* * No need to try to free the PUD page because we'll free it in * populate_pgd's error path */ } static void unmap_pgd_range(pgd_t *root, unsigned long addr, unsigned long end) { pgd_t *pgd_entry = root + pgd_index(addr); unmap_pud_range(pgd_entry, addr, end); if (try_to_free_pud_page((pud_t *)pgd_page_vaddr(*pgd_entry))) pgd_clear(pgd_entry); } static int alloc_pte_page(pmd_t *pmd) { pte_t *pte = (pte_t *)get_zeroed_page(GFP_KERNEL | __GFP_NOTRACK); if (!pte) return -1; set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE)); return 0; } static int alloc_pmd_page(pud_t *pud) { pmd_t *pmd = (pmd_t *)get_zeroed_page(GFP_KERNEL | __GFP_NOTRACK); if (!pmd) return -1; set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE)); return 0; } static void populate_pte(struct cpa_data *cpa, unsigned long start, unsigned long end, unsigned num_pages, pmd_t *pmd, pgprot_t pgprot) { pte_t *pte; pte = pte_offset_kernel(pmd, start); while (num_pages-- && start < end) { /* deal with the NX bit */ if (!(pgprot_val(pgprot) & _PAGE_NX)) cpa->pfn &= ~_PAGE_NX; set_pte(pte, pfn_pte(cpa->pfn >> PAGE_SHIFT, pgprot)); start += PAGE_SIZE; cpa->pfn += PAGE_SIZE; pte++; } } static int populate_pmd(struct cpa_data *cpa, unsigned long start, unsigned long end, unsigned num_pages, pud_t *pud, pgprot_t pgprot) { unsigned int cur_pages = 0; pmd_t *pmd; /* * Not on a 2M boundary? */ if (start & (PMD_SIZE - 1)) { unsigned long pre_end = start + (num_pages << PAGE_SHIFT); unsigned long next_page = (start + PMD_SIZE) & PMD_MASK; pre_end = min_t(unsigned long, pre_end, next_page); cur_pages = (pre_end - start) >> PAGE_SHIFT; cur_pages = min_t(unsigned int, num_pages, cur_pages); /* * Need a PTE page? */ pmd = pmd_offset(pud, start); if (pmd_none(*pmd)) if (alloc_pte_page(pmd)) return -1; populate_pte(cpa, start, pre_end, cur_pages, pmd, pgprot); start = pre_end; } /* * We mapped them all? */ if (num_pages == cur_pages) return cur_pages; while (end - start >= PMD_SIZE) { /* * We cannot use a 1G page so allocate a PMD page if needed. */ if (pud_none(*pud)) if (alloc_pmd_page(pud)) return -1; pmd = pmd_offset(pud, start); set_pmd(pmd, __pmd(cpa->pfn | _PAGE_PSE | massage_pgprot(pgprot))); start += PMD_SIZE; cpa->pfn += PMD_SIZE; cur_pages += PMD_SIZE >> PAGE_SHIFT; } /* * Map trailing 4K pages. */ if (start < end) { pmd = pmd_offset(pud, start); if (pmd_none(*pmd)) if (alloc_pte_page(pmd)) return -1; populate_pte(cpa, start, end, num_pages - cur_pages, pmd, pgprot); } return num_pages; } static int populate_pud(struct cpa_data *cpa, unsigned long start, pgd_t *pgd, pgprot_t pgprot) { pud_t *pud; unsigned long end; int cur_pages = 0; end = start + (cpa->numpages << PAGE_SHIFT); /* * Not on a Gb page boundary? => map everything up to it with * smaller pages. */ if (start & (PUD_SIZE - 1)) { unsigned long pre_end; unsigned long next_page = (start + PUD_SIZE) & PUD_MASK; pre_end = min_t(unsigned long, end, next_page); cur_pages = (pre_end - start) >> PAGE_SHIFT; cur_pages = min_t(int, (int)cpa->numpages, cur_pages); pud = pud_offset(pgd, start); /* * Need a PMD page? */ if (pud_none(*pud)) if (alloc_pmd_page(pud)) return -1; cur_pages = populate_pmd(cpa, start, pre_end, cur_pages, pud, pgprot); if (cur_pages < 0) return cur_pages; start = pre_end; } /* We mapped them all? */ if (cpa->numpages == cur_pages) return cur_pages; pud = pud_offset(pgd, start); /* * Map everything starting from the Gb boundary, possibly with 1G pages */ while (end - start >= PUD_SIZE) { set_pud(pud, __pud(cpa->pfn | _PAGE_PSE | massage_pgprot(pgprot))); start += PUD_SIZE; cpa->pfn += PUD_SIZE; cur_pages += PUD_SIZE >> PAGE_SHIFT; pud++; } /* Map trailing leftover */ if (start < end) { int tmp; pud = pud_offset(pgd, start); if (pud_none(*pud)) if (alloc_pmd_page(pud)) return -1; tmp = populate_pmd(cpa, start, end, cpa->numpages - cur_pages, pud, pgprot); if (tmp < 0) return cur_pages; cur_pages += tmp; } return cur_pages; } /* * Restrictions for kernel page table do not necessarily apply when mapping in * an alternate PGD. */ static int populate_pgd(struct cpa_data *cpa, unsigned long addr) { pgprot_t pgprot = __pgprot(_KERNPG_TABLE); pud_t *pud = NULL; /* shut up gcc */ pgd_t *pgd_entry; int ret; pgd_entry = cpa->pgd + pgd_index(addr); /* * Allocate a PUD page and hand it down for mapping. */ if (pgd_none(*pgd_entry)) { pud = (pud_t *)get_zeroed_page(GFP_KERNEL | __GFP_NOTRACK); if (!pud) return -1; set_pgd(pgd_entry, __pgd(__pa(pud) | _KERNPG_TABLE)); } pgprot_val(pgprot) &= ~pgprot_val(cpa->mask_clr); pgprot_val(pgprot) |= pgprot_val(cpa->mask_set); ret = populate_pud(cpa, addr, pgd_entry, pgprot); if (ret < 0) { unmap_pgd_range(cpa->pgd, addr, addr + (cpa->numpages << PAGE_SHIFT)); return ret; } cpa->numpages = ret; return 0; } static int __cpa_process_fault(struct cpa_data *cpa, unsigned long vaddr, int primary) { if (cpa->pgd) return populate_pgd(cpa, vaddr); /* * Ignore all non primary paths. */ if (!primary) return 0; /* * Ignore the NULL PTE for kernel identity mapping, as it is expected * to have holes. * Also set numpages to '1' indicating that we processed cpa req for * one virtual address page and its pfn. TBD: numpages can be set based * on the initial value and the level returned by lookup_address(). */ if (within(vaddr, PAGE_OFFSET, PAGE_OFFSET + (max_pfn_mapped << PAGE_SHIFT))) { cpa->numpages = 1; cpa->pfn = __pa(vaddr) >> PAGE_SHIFT; return 0; } else { WARN(1, KERN_WARNING "CPA: called for zero pte. " "vaddr = %lx cpa->vaddr = %lx\n", vaddr, *cpa->vaddr); return -EFAULT; } } static int __change_page_attr(struct cpa_data *cpa, int primary) { unsigned long address; int do_split, err; unsigned int level; pte_t *kpte, old_pte; if (cpa->flags & CPA_PAGES_ARRAY) { struct page *page = cpa->pages[cpa->curpage]; if (unlikely(PageHighMem(page))) return 0; address = (unsigned long)page_address(page); } else if (cpa->flags & CPA_ARRAY) address = cpa->vaddr[cpa->curpage]; else address = *cpa->vaddr; repeat: kpte = _lookup_address_cpa(cpa, address, &level); if (!kpte) return __cpa_process_fault(cpa, address, primary); old_pte = *kpte; if (!pte_val(old_pte)) return __cpa_process_fault(cpa, address, primary); if (level == PG_LEVEL_4K) { pte_t new_pte; pgprot_t new_prot = pte_pgprot(old_pte); unsigned long pfn = pte_pfn(old_pte); pgprot_val(new_prot) &= ~pgprot_val(cpa->mask_clr); pgprot_val(new_prot) |= pgprot_val(cpa->mask_set); new_prot = static_protections(new_prot, address, pfn); /* * Set the GLOBAL flags only if the PRESENT flag is * set otherwise pte_present will return true even on * a non present pte. The canon_pgprot will clear * _PAGE_GLOBAL for the ancient hardware that doesn't * support it. */ if (pgprot_val(new_prot) & _PAGE_PRESENT) pgprot_val(new_prot) |= _PAGE_GLOBAL; else pgprot_val(new_prot) &= ~_PAGE_GLOBAL; /* * We need to keep the pfn from the existing PTE, * after all we're only going to change it's attributes * not the memory it points to */ new_pte = pfn_pte(pfn, canon_pgprot(new_prot)); cpa->pfn = pfn; /* * Do we really change anything ? */ if (pte_val(old_pte) != pte_val(new_pte)) { set_pte_atomic(kpte, new_pte); cpa->flags |= CPA_FLUSHTLB; } cpa->numpages = 1; return 0; } /* * Check, whether we can keep the large page intact * and just change the pte: */ do_split = try_preserve_large_page(kpte, address, cpa); /* * When the range fits into the existing large page, * return. cp->numpages and cpa->tlbflush have been updated in * try_large_page: */ if (do_split <= 0) return do_split; /* * We have to split the large page: */ err = split_large_page(cpa, kpte, address); if (!err) { /* * Do a global flush tlb after splitting the large page * and before we do the actual change page attribute in the PTE. * * With out this, we violate the TLB application note, that says * "The TLBs may contain both ordinary and large-page * translations for a 4-KByte range of linear addresses. This * may occur if software modifies the paging structures so that * the page size used for the address range changes. If the two * translations differ with respect to page frame or attributes * (e.g., permissions), processor behavior is undefined and may * be implementation-specific." * * We do this global tlb flush inside the cpa_lock, so that we * don't allow any other cpu, with stale tlb entries change the * page attribute in parallel, that also falls into the * just split large page entry. */ flush_tlb_all(); goto repeat; } return err; } static int __change_page_attr_set_clr(struct cpa_data *cpa, int checkalias); static int cpa_process_alias(struct cpa_data *cpa) { struct cpa_data alias_cpa; unsigned long laddr = (unsigned long)__va(cpa->pfn << PAGE_SHIFT); unsigned long vaddr; int ret; if (!pfn_range_is_mapped(cpa->pfn, cpa->pfn + 1)) return 0; /* * No need to redo, when the primary call touched the direct * mapping already: */ if (cpa->flags & CPA_PAGES_ARRAY) { struct page *page = cpa->pages[cpa->curpage]; if (unlikely(PageHighMem(page))) return 0; vaddr = (unsigned long)page_address(page); } else if (cpa->flags & CPA_ARRAY) vaddr = cpa->vaddr[cpa->curpage]; else vaddr = *cpa->vaddr; if (!(within(vaddr, PAGE_OFFSET, PAGE_OFFSET + (max_pfn_mapped << PAGE_SHIFT)))) { alias_cpa = *cpa; alias_cpa.vaddr = &laddr; alias_cpa.flags &= ~(CPA_PAGES_ARRAY | CPA_ARRAY); ret = __change_page_attr_set_clr(&alias_cpa, 0); if (ret) return ret; } #ifdef CONFIG_X86_64 /* * If the primary call didn't touch the high mapping already * and the physical address is inside the kernel map, we need * to touch the high mapped kernel as well: */ if (!within(vaddr, (unsigned long)_text, _brk_end) && within(cpa->pfn, highmap_start_pfn(), highmap_end_pfn())) { unsigned long temp_cpa_vaddr = (cpa->pfn << PAGE_SHIFT) + __START_KERNEL_map - phys_base; alias_cpa = *cpa; alias_cpa.vaddr = &temp_cpa_vaddr; alias_cpa.flags &= ~(CPA_PAGES_ARRAY | CPA_ARRAY); /* * The high mapping range is imprecise, so ignore the * return value. */ __change_page_attr_set_clr(&alias_cpa, 0); } #endif return 0; } static int __change_page_attr_set_clr(struct cpa_data *cpa, int checkalias) { int ret, numpages = cpa->numpages; while (numpages) { /* * Store the remaining nr of pages for the large page * preservation check. */ cpa->numpages = numpages; /* for array changes, we can't use large page */ if (cpa->flags & (CPA_ARRAY | CPA_PAGES_ARRAY)) cpa->numpages = 1; if (!debug_pagealloc) spin_lock(&cpa_lock); ret = __change_page_attr(cpa, checkalias); if (!debug_pagealloc) spin_unlock(&cpa_lock); if (ret) return ret; if (checkalias) { ret = cpa_process_alias(cpa); if (ret) return ret; } /* * Adjust the number of pages with the result of the * CPA operation. Either a large page has been * preserved or a single page update happened. */ BUG_ON(cpa->numpages > numpages); numpages -= cpa->numpages; if (cpa->flags & (CPA_PAGES_ARRAY | CPA_ARRAY)) cpa->curpage++; else *cpa->vaddr += cpa->numpages * PAGE_SIZE; } return 0; } static inline int cache_attr(pgprot_t attr) { return pgprot_val(attr) & (_PAGE_PAT | _PAGE_PAT_LARGE | _PAGE_PWT | _PAGE_PCD); } static int change_page_attr_set_clr(unsigned long *addr, int numpages, pgprot_t mask_set, pgprot_t mask_clr, int force_split, int in_flag, struct page **pages) { struct cpa_data cpa; int ret, cache, checkalias; unsigned long baddr = 0; memset(&cpa, 0, sizeof(cpa)); /* * Check, if we are requested to change a not supported * feature: */ mask_set = canon_pgprot(mask_set); mask_clr = canon_pgprot(mask_clr); if (!pgprot_val(mask_set) && !pgprot_val(mask_clr) && !force_split) return 0; /* Ensure we are PAGE_SIZE aligned */ if (in_flag & CPA_ARRAY) { int i; for (i = 0; i < numpages; i++) { if (addr[i] & ~PAGE_MASK) { addr[i] &= PAGE_MASK; WARN_ON_ONCE(1); } } } else if (!(in_flag & CPA_PAGES_ARRAY)) { /* * in_flag of CPA_PAGES_ARRAY implies it is aligned. * No need to cehck in that case */ if (*addr & ~PAGE_MASK) { *addr &= PAGE_MASK; /* * People should not be passing in unaligned addresses: */ WARN_ON_ONCE(1); } /* * Save address for cache flush. *addr is modified in the call * to __change_page_attr_set_clr() below. */ baddr = *addr; } /* Must avoid aliasing mappings in the highmem code */ kmap_flush_unused(); vm_unmap_aliases(); cpa.vaddr = addr; cpa.pages = pages; cpa.numpages = numpages; cpa.mask_set = mask_set; cpa.mask_clr = mask_clr; cpa.flags = 0; cpa.curpage = 0; cpa.force_split = force_split; if (in_flag & (CPA_ARRAY | CPA_PAGES_ARRAY)) cpa.flags |= in_flag; /* No alias checking for _NX bit modifications */ checkalias = (pgprot_val(mask_set) | pgprot_val(mask_clr)) != _PAGE_NX; ret = __change_page_attr_set_clr(&cpa, checkalias); /* * Check whether we really changed something: */ if (!(cpa.flags & CPA_FLUSHTLB)) goto out; /* * No need to flush, when we did not set any of the caching * attributes: */ cache = cache_attr(mask_set); /* * On success we use clflush, when the CPU supports it to * avoid the wbindv. If the CPU does not support it and in the * error case we fall back to cpa_flush_all (which uses * wbindv): */ if (!ret && cpu_has_clflush) { if (cpa.flags & (CPA_PAGES_ARRAY | CPA_ARRAY)) { cpa_flush_array(addr, numpages, cache, cpa.flags, pages); } else cpa_flush_range(baddr, numpages, cache); } else cpa_flush_all(cache); out: return ret; } static inline int change_page_attr_set(unsigned long *addr, int numpages, pgprot_t mask, int array) { return change_page_attr_set_clr(addr, numpages, mask, __pgprot(0), 0, (array ? CPA_ARRAY : 0), NULL); } static inline int change_page_attr_clear(unsigned long *addr, int numpages, pgprot_t mask, int array) { return change_page_attr_set_clr(addr, numpages, __pgprot(0), mask, 0, (array ? CPA_ARRAY : 0), NULL); } static inline int cpa_set_pages_array(struct page **pages, int numpages, pgprot_t mask) { return change_page_attr_set_clr(NULL, numpages, mask, __pgprot(0), 0, CPA_PAGES_ARRAY, pages); } static inline int cpa_clear_pages_array(struct page **pages, int numpages, pgprot_t mask) { return change_page_attr_set_clr(NULL, numpages, __pgprot(0), mask, 0, CPA_PAGES_ARRAY, pages); } int _set_memory_uc(unsigned long addr, int numpages) { /* * for now UC MINUS. see comments in ioremap_nocache() */ return change_page_attr_set(&addr, numpages, __pgprot(_PAGE_CACHE_UC_MINUS), 0); } int set_memory_uc(unsigned long addr, int numpages) { int ret; /* * for now UC MINUS. see comments in ioremap_nocache() */ ret = reserve_memtype(__pa(addr), __pa(addr) + numpages * PAGE_SIZE, _PAGE_CACHE_UC_MINUS, NULL); if (ret) goto out_err; ret = _set_memory_uc(addr, numpages); if (ret) goto out_free; return 0; out_free: free_memtype(__pa(addr), __pa(addr) + numpages * PAGE_SIZE); out_err: return ret; } EXPORT_SYMBOL(set_memory_uc); static int _set_memory_array(unsigned long *addr, int addrinarray, unsigned long new_type) { int i, j; int ret; /* * for now UC MINUS. see comments in ioremap_nocache() */ for (i = 0; i < addrinarray; i++) { ret = reserve_memtype(__pa(addr[i]), __pa(addr[i]) + PAGE_SIZE, new_type, NULL); if (ret) goto out_free; } ret = change_page_attr_set(addr, addrinarray, __pgprot(_PAGE_CACHE_UC_MINUS), 1); if (!ret && new_type == _PAGE_CACHE_WC) ret = change_page_attr_set_clr(addr, addrinarray, __pgprot(_PAGE_CACHE_WC), __pgprot(_PAGE_CACHE_MASK), 0, CPA_ARRAY, NULL); if (ret) goto out_free; return 0; out_free: for (j = 0; j < i; j++) free_memtype(__pa(addr[j]), __pa(addr[j]) + PAGE_SIZE); return ret; } int set_memory_array_uc(unsigned long *addr, int addrinarray) { return _set_memory_array(addr, addrinarray, _PAGE_CACHE_UC_MINUS); } EXPORT_SYMBOL(set_memory_array_uc); int set_memory_array_wc(unsigned long *addr, int addrinarray) { return _set_memory_array(addr, addrinarray, _PAGE_CACHE_WC); } EXPORT_SYMBOL(set_memory_array_wc); int _set_memory_wc(unsigned long addr, int numpages) { int ret; unsigned long addr_copy = addr; ret = change_page_attr_set(&addr, numpages, __pgprot(_PAGE_CACHE_UC_MINUS), 0); if (!ret) { ret = change_page_attr_set_clr(&addr_copy, numpages, __pgprot(_PAGE_CACHE_WC), __pgprot(_PAGE_CACHE_MASK), 0, 0, NULL); } return ret; } int set_memory_wc(unsigned long addr, int numpages) { int ret; if (!pat_enabled) return set_memory_uc(addr, numpages); ret = reserve_memtype(__pa(addr), __pa(addr) + numpages * PAGE_SIZE, _PAGE_CACHE_WC, NULL); if (ret) goto out_err; ret = _set_memory_wc(addr, numpages); if (ret) goto out_free; return 0; out_free: free_memtype(__pa(addr), __pa(addr) + numpages * PAGE_SIZE); out_err: return ret; } EXPORT_SYMBOL(set_memory_wc); int _set_memory_wb(unsigned long addr, int numpages) { return change_page_attr_clear(&addr, numpages, __pgprot(_PAGE_CACHE_MASK), 0); } int set_memory_wb(unsigned long addr, int numpages) { int ret; ret = _set_memory_wb(addr, numpages); if (ret) return ret; free_memtype(__pa(addr), __pa(addr) + numpages * PAGE_SIZE); return 0; } EXPORT_SYMBOL(set_memory_wb); int set_memory_array_wb(unsigned long *addr, int addrinarray) { int i; int ret; ret = change_page_attr_clear(addr, addrinarray, __pgprot(_PAGE_CACHE_MASK), 1); if (ret) return ret; for (i = 0; i < addrinarray; i++) free_memtype(__pa(addr[i]), __pa(addr[i]) + PAGE_SIZE); return 0; } EXPORT_SYMBOL(set_memory_array_wb); int set_memory_x(unsigned long addr, int numpages) { if (!(__supported_pte_mask & _PAGE_NX)) return 0; return change_page_attr_clear(&addr, numpages, __pgprot(_PAGE_NX), 0); } EXPORT_SYMBOL(set_memory_x); int set_memory_nx(unsigned long addr, int numpages) { if (!(__supported_pte_mask & _PAGE_NX)) return 0; return change_page_attr_set(&addr, numpages, __pgprot(_PAGE_NX), 0); } EXPORT_SYMBOL(set_memory_nx); int set_memory_ro(unsigned long addr, int numpages) { return change_page_attr_clear(&addr, numpages, __pgprot(_PAGE_RW), 0); } EXPORT_SYMBOL_GPL(set_memory_ro); int set_memory_rw(unsigned long addr, int numpages) { return change_page_attr_set(&addr, numpages, __pgprot(_PAGE_RW), 0); } EXPORT_SYMBOL_GPL(set_memory_rw); int set_memory_np(unsigned long addr, int numpages) { return change_page_attr_clear(&addr, numpages, __pgprot(_PAGE_PRESENT), 0); } int set_memory_4k(unsigned long addr, int numpages) { return change_page_attr_set_clr(&addr, numpages, __pgprot(0), __pgprot(0), 1, 0, NULL); } int set_pages_uc(struct page *page, int numpages) { unsigned long addr = (unsigned long)page_address(page); return set_memory_uc(addr, numpages); } EXPORT_SYMBOL(set_pages_uc); static int _set_pages_array(struct page **pages, int addrinarray, unsigned long new_type) { unsigned long start; unsigned long end; int i; int free_idx; int ret; for (i = 0; i < addrinarray; i++) { if (PageHighMem(pages[i])) continue; start = page_to_pfn(pages[i]) << PAGE_SHIFT; end = start + PAGE_SIZE; if (reserve_memtype(start, end, new_type, NULL)) goto err_out; } ret = cpa_set_pages_array(pages, addrinarray, __pgprot(_PAGE_CACHE_UC_MINUS)); if (!ret && new_type == _PAGE_CACHE_WC) ret = change_page_attr_set_clr(NULL, addrinarray, __pgprot(_PAGE_CACHE_WC), __pgprot(_PAGE_CACHE_MASK), 0, CPA_PAGES_ARRAY, pages); if (ret) goto err_out; return 0; /* Success */ err_out: free_idx = i; for (i = 0; i < free_idx; i++) { if (PageHighMem(pages[i])) continue; start = page_to_pfn(pages[i]) << PAGE_SHIFT; end = start + PAGE_SIZE; free_memtype(start, end); } return -EINVAL; } int set_pages_array_uc(struct page **pages, int addrinarray) { return _set_pages_array(pages, addrinarray, _PAGE_CACHE_UC_MINUS); } EXPORT_SYMBOL(set_pages_array_uc); int set_pages_array_wc(struct page **pages, int addrinarray) { return _set_pages_array(pages, addrinarray, _PAGE_CACHE_WC); } EXPORT_SYMBOL(set_pages_array_wc); int set_pages_wb(struct page *page, int numpages) { unsigned long addr = (unsigned long)page_address(page); return set_memory_wb(addr, numpages); } EXPORT_SYMBOL(set_pages_wb); int set_pages_array_wb(struct page **pages, int addrinarray) { int retval; unsigned long start; unsigned long end; int i; retval = cpa_clear_pages_array(pages, addrinarray, __pgprot(_PAGE_CACHE_MASK)); if (retval) return retval; for (i = 0; i < addrinarray; i++) { if (PageHighMem(pages[i])) continue; start = page_to_pfn(pages[i]) << PAGE_SHIFT; end = start + PAGE_SIZE; free_memtype(start, end); } return 0; } EXPORT_SYMBOL(set_pages_array_wb); int set_pages_x(struct page *page, int numpages) { unsigned long addr = (unsigned long)page_address(page); return set_memory_x(addr, numpages); } EXPORT_SYMBOL(set_pages_x); int set_pages_nx(struct page *page, int numpages) { unsigned long addr = (unsigned long)page_address(page); return set_memory_nx(addr, numpages); } EXPORT_SYMBOL(set_pages_nx); int set_pages_ro(struct page *page, int numpages) { unsigned long addr = (unsigned long)page_address(page); return set_memory_ro(addr, numpages); } int set_pages_rw(struct page *page, int numpages) { unsigned long addr = (unsigned long)page_address(page); return set_memory_rw(addr, numpages); } #ifdef CONFIG_DEBUG_PAGEALLOC static int __set_pages_p(struct page *page, int numpages) { unsigned long tempaddr = (unsigned long) page_address(page); struct cpa_data cpa = { .vaddr = &tempaddr, .pgd = NULL, .numpages = numpages, .mask_set = __pgprot(_PAGE_PRESENT | _PAGE_RW), .mask_clr = __pgprot(0), .flags = 0}; /* * No alias checking needed for setting present flag. otherwise, * we may need to break large pages for 64-bit kernel text * mappings (this adds to complexity if we want to do this from * atomic context especially). Let's keep it simple! */ return __change_page_attr_set_clr(&cpa, 0); } static int __set_pages_np(struct page *page, int numpages) { unsigned long tempaddr = (unsigned long) page_address(page); struct cpa_data cpa = { .vaddr = &tempaddr, .pgd = NULL, .numpages = numpages, .mask_set = __pgprot(0), .mask_clr = __pgprot(_PAGE_PRESENT | _PAGE_RW), .flags = 0}; /* * No alias checking needed for setting not present flag. otherwise, * we may need to break large pages for 64-bit kernel text * mappings (this adds to complexity if we want to do this from * atomic context especially). Let's keep it simple! */ return __change_page_attr_set_clr(&cpa, 0); } void kernel_map_pages(struct page *page, int numpages, int enable) { if (PageHighMem(page)) return; if (!enable) { debug_check_no_locks_freed(page_address(page), numpages * PAGE_SIZE); } /* * The return value is ignored as the calls cannot fail. * Large pages for identity mappings are not used at boot time * and hence no memory allocations during large page split. */ if (enable) __set_pages_p(page, numpages); else __set_pages_np(page, numpages); /* * We should perform an IPI and flush all tlbs, * but that can deadlock->flush only current cpu: */ __flush_tlb_all(); arch_flush_lazy_mmu_mode(); } #ifdef CONFIG_HIBERNATION bool kernel_page_present(struct page *page) { unsigned int level; pte_t *pte; if (PageHighMem(page)) return false; pte = lookup_address((unsigned long)page_address(page), &level); return (pte_val(*pte) & _PAGE_PRESENT); } #endif /* CONFIG_HIBERNATION */ #endif /* CONFIG_DEBUG_PAGEALLOC */ int kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, unsigned long address, unsigned numpages, unsigned long page_flags) { int retval = -EINVAL; struct cpa_data cpa = { .vaddr = &address, .pfn = pfn, .pgd = pgd, .numpages = numpages, .mask_set = __pgprot(0), .mask_clr = __pgprot(0), .flags = 0, }; if (!(__supported_pte_mask & _PAGE_NX)) goto out; if (!(page_flags & _PAGE_NX)) cpa.mask_clr = __pgprot(_PAGE_NX); cpa.mask_set = __pgprot(_PAGE_PRESENT | page_flags); retval = __change_page_attr_set_clr(&cpa, 0); __flush_tlb_all(); out: return retval; } void kernel_unmap_pages_in_pgd(pgd_t *root, unsigned long address, unsigned numpages) { unmap_pgd_range(root, address, address + (numpages << PAGE_SHIFT)); } /* * The testcases use internal knowledge of the implementation that shouldn't * be exposed to the rest of the kernel. Include these directly here. */ #ifdef CONFIG_CPA_DEBUG #include "pageattr-test.c" #endif