2 * Copyright 2002 Andi Kleen, SuSE Labs.
3 * Thanks to Ben LaHaise for precious feedback.
5 #include <linux/highmem.h>
6 #include <linux/bootmem.h>
7 #include <linux/module.h>
8 #include <linux/sched.h>
9 #include <linux/slab.h>
13 #include <asm/processor.h>
14 #include <asm/tlbflush.h>
15 #include <asm/sections.h>
16 #include <asm/uaccess.h>
17 #include <asm/pgalloc.h>
20 within(unsigned long addr, unsigned long start, unsigned long end)
22 return addr >= start && addr < end;
30 * clflush_cache_range - flush a cache range with clflush
31 * @addr: virtual start address
32 * @size: number of bytes to flush
34 * clflush is an unordered instruction which needs fencing with mfence
35 * to avoid ordering issues.
37 void clflush_cache_range(void *vaddr, unsigned int size)
39 void *vend = vaddr + size - 1;
43 for (; vaddr < vend; vaddr += boot_cpu_data.x86_clflush_size)
46 * Flush any possible final partial cacheline:
53 static void __cpa_flush_all(void *arg)
56 * Flush all to work around Errata in early athlons regarding
57 * large page flushing.
61 if (boot_cpu_data.x86_model >= 4)
65 static void cpa_flush_all(void)
67 BUG_ON(irqs_disabled());
69 on_each_cpu(__cpa_flush_all, NULL, 1, 1);
72 static void __cpa_flush_range(void *arg)
75 * We could optimize that further and do individual per page
76 * tlb invalidates for a low number of pages. Caveat: we must
77 * flush the high aliases on 64bit as well.
82 static void cpa_flush_range(unsigned long start, int numpages)
84 unsigned int i, level;
87 BUG_ON(irqs_disabled());
88 WARN_ON(PAGE_ALIGN(start) != start);
90 on_each_cpu(__cpa_flush_range, NULL, 1, 1);
93 * We only need to flush on one CPU,
94 * clflush is a MESI-coherent instruction that
95 * will cause all other CPUs to flush the same
98 for (i = 0, addr = start; i < numpages; i++, addr += PAGE_SIZE) {
99 pte_t *pte = lookup_address(addr, &level);
102 * Only flush present addresses:
104 if (pte && pte_present(*pte))
105 clflush_cache_range((void *) addr, PAGE_SIZE);
109 #define HIGH_MAP_START __START_KERNEL_map
110 #define HIGH_MAP_END (__START_KERNEL_map + KERNEL_TEXT_SIZE)
114 * Converts a virtual address to a X86-64 highmap address
116 static unsigned long virt_to_highmap(void *address)
119 return __pa((unsigned long)address) + HIGH_MAP_START - phys_base;
121 return (unsigned long)address;
126 * Certain areas of memory on x86 require very specific protection flags,
127 * for example the BIOS area or kernel text. Callers don't always get this
128 * right (again, ioremap() on BIOS memory is not uncommon) so this function
129 * checks and fixes these known static required protection bits.
131 static inline pgprot_t static_protections(pgprot_t prot, unsigned long address)
133 pgprot_t forbidden = __pgprot(0);
136 * The BIOS area between 640k and 1Mb needs to be executable for
137 * PCI BIOS based config access (CONFIG_PCI_GOBIOS) support.
139 if (within(__pa(address), BIOS_BEGIN, BIOS_END))
140 pgprot_val(forbidden) |= _PAGE_NX;
143 * The kernel text needs to be executable for obvious reasons
144 * Does not cover __inittext since that is gone later on
146 if (within(address, (unsigned long)_text, (unsigned long)_etext))
147 pgprot_val(forbidden) |= _PAGE_NX;
149 * Do the same for the x86-64 high kernel mapping
151 if (within(address, virt_to_highmap(_text), virt_to_highmap(_etext)))
152 pgprot_val(forbidden) |= _PAGE_NX;
155 #ifdef CONFIG_DEBUG_RODATA
156 /* The .rodata section needs to be read-only */
157 if (within(address, (unsigned long)__start_rodata,
158 (unsigned long)__end_rodata))
159 pgprot_val(forbidden) |= _PAGE_RW;
161 * Do the same for the x86-64 high kernel mapping
163 if (within(address, virt_to_highmap(__start_rodata),
164 virt_to_highmap(__end_rodata)))
165 pgprot_val(forbidden) |= _PAGE_RW;
168 prot = __pgprot(pgprot_val(prot) & ~pgprot_val(forbidden));
173 pte_t *lookup_address(unsigned long address, int *level)
175 pgd_t *pgd = pgd_offset_k(address);
179 *level = PG_LEVEL_NONE;
183 pud = pud_offset(pgd, address);
186 pmd = pmd_offset(pud, address);
190 *level = PG_LEVEL_2M;
194 *level = PG_LEVEL_4K;
195 return pte_offset_kernel(pmd, address);
198 static void __set_pmd_pte(pte_t *kpte, unsigned long address, pte_t pte)
201 set_pte_atomic(kpte, pte);
203 if (!SHARED_KERNEL_PMD) {
206 list_for_each_entry(page, &pgd_list, lru) {
211 pgd = (pgd_t *)page_address(page) + pgd_index(address);
212 pud = pud_offset(pgd, address);
213 pmd = pmd_offset(pud, address);
214 set_pte_atomic((pte_t *)pmd, pte);
220 static int split_large_page(pte_t *kpte, unsigned long address)
222 pgprot_t ref_prot = pte_pgprot(pte_clrhuge(*kpte));
223 gfp_t gfp_flags = GFP_KERNEL;
224 unsigned long flags, addr, pfn;
227 unsigned int i, level;
229 #ifdef CONFIG_DEBUG_PAGEALLOC
230 gfp_flags = __GFP_HIGH | __GFP_NOFAIL | __GFP_NOWARN;
231 gfp_flags = GFP_ATOMIC | __GFP_NOWARN;
233 base = alloc_pages(gfp_flags, 0);
237 spin_lock_irqsave(&pgd_lock, flags);
239 * Check for races, another CPU might have split this page
242 tmp = lookup_address(address, &level);
248 address = __pa(address);
249 addr = address & LARGE_PAGE_MASK;
250 pbase = (pte_t *)page_address(base);
252 paravirt_alloc_pt(&init_mm, page_to_pfn(base));
256 * Get the target pfn from the original entry:
258 pfn = pte_pfn(*kpte);
259 for (i = 0; i < PTRS_PER_PTE; i++, pfn++)
260 set_pte(&pbase[i], pfn_pte(pfn, ref_prot));
263 * Install the new, split up pagetable. Important detail here:
265 * On Intel the NX bit of all levels must be cleared to make a
266 * page executable. See section 4.13.2 of Intel 64 and IA-32
267 * Architectures Software Developer's Manual).
269 ref_prot = pte_pgprot(pte_mkexec(pte_clrhuge(*kpte)));
270 __set_pmd_pte(kpte, address, mk_pte(base, ref_prot));
274 spin_unlock_irqrestore(&pgd_lock, flags);
277 __free_pages(base, 0);
283 __change_page_attr(unsigned long address, pgprot_t mask_set, pgprot_t mask_clr)
285 struct page *kpte_page;
290 kpte = lookup_address(address, &level);
294 kpte_page = virt_to_page(kpte);
295 BUG_ON(PageLRU(kpte_page));
296 BUG_ON(PageCompound(kpte_page));
298 if (level == PG_LEVEL_4K) {
299 pte_t new_pte, old_pte = *kpte;
300 pgprot_t new_prot = pte_pgprot(old_pte);
302 if(!pte_val(old_pte)) {
307 pgprot_val(new_prot) &= ~pgprot_val(mask_clr);
308 pgprot_val(new_prot) |= pgprot_val(mask_set);
310 new_prot = static_protections(new_prot, address);
313 * We need to keep the pfn from the existing PTE,
314 * after all we're only going to change it's attributes
315 * not the memory it points to
317 new_pte = pfn_pte(pte_pfn(old_pte), canon_pgprot(new_prot));
318 set_pte_atomic(kpte, new_pte);
320 err = split_large_page(kpte, address);
328 * change_page_attr_addr - Change page table attributes in linear mapping
329 * @address: Virtual address in linear mapping.
330 * @prot: New page table attribute (PAGE_*)
332 * Change page attributes of a page in the direct mapping. This is a variant
333 * of change_page_attr() that also works on memory holes that do not have
334 * mem_map entry (pfn_valid() is false).
336 * See change_page_attr() documentation for more details.
338 * Modules and drivers should use the set_memory_* APIs instead.
343 change_page_attr_addr(unsigned long address, pgprot_t mask_set,
349 unsigned long phys_addr = __pa(address);
352 * If we are inside the high mapped kernel range, then we
353 * fixup the low mapping first. __va() returns the virtual
354 * address in the linear mapping:
356 if (within(address, HIGH_MAP_START, HIGH_MAP_END))
357 address = (unsigned long) __va(phys_addr);
360 err = __change_page_attr(address, mask_set, mask_clr);
366 * If the physical address is inside the kernel map, we need
367 * to touch the high mapped kernel as well:
369 if (within(phys_addr, 0, KERNEL_TEXT_SIZE)) {
371 * Calc the high mapping address. See __phys_addr()
372 * for the non obvious details.
374 * Note that NX and other required permissions are
375 * checked in static_protections().
377 address = phys_addr + HIGH_MAP_START - phys_base;
380 * Our high aliases are imprecise, because we check
381 * everything between 0 and KERNEL_TEXT_SIZE, so do
382 * not propagate lookup failures back to users:
384 __change_page_attr(address, mask_set, mask_clr);
390 static int __change_page_attr_set_clr(unsigned long addr, int numpages,
391 pgprot_t mask_set, pgprot_t mask_clr)
396 for (i = 0; i < numpages ; i++, addr += PAGE_SIZE) {
397 ret = change_page_attr_addr(addr, mask_set, mask_clr);
405 static int change_page_attr_set_clr(unsigned long addr, int numpages,
406 pgprot_t mask_set, pgprot_t mask_clr)
408 int ret = __change_page_attr_set_clr(addr, numpages, mask_set,
412 * On success we use clflush, when the CPU supports it to
413 * avoid the wbindv. If the CPU does not support it and in the
414 * error case we fall back to cpa_flush_all (which uses
417 if (!ret && cpu_has_clflush)
418 cpa_flush_range(addr, numpages);
425 static inline int change_page_attr_set(unsigned long addr, int numpages,
428 return change_page_attr_set_clr(addr, numpages, mask, __pgprot(0));
431 static inline int change_page_attr_clear(unsigned long addr, int numpages,
434 return change_page_attr_set_clr(addr, numpages, __pgprot(0), mask);
437 int set_memory_uc(unsigned long addr, int numpages)
439 return change_page_attr_set(addr, numpages,
440 __pgprot(_PAGE_PCD | _PAGE_PWT));
442 EXPORT_SYMBOL(set_memory_uc);
444 int set_memory_wb(unsigned long addr, int numpages)
446 return change_page_attr_clear(addr, numpages,
447 __pgprot(_PAGE_PCD | _PAGE_PWT));
449 EXPORT_SYMBOL(set_memory_wb);
451 int set_memory_x(unsigned long addr, int numpages)
453 return change_page_attr_clear(addr, numpages, __pgprot(_PAGE_NX));
455 EXPORT_SYMBOL(set_memory_x);
457 int set_memory_nx(unsigned long addr, int numpages)
459 return change_page_attr_set(addr, numpages, __pgprot(_PAGE_NX));
461 EXPORT_SYMBOL(set_memory_nx);
463 int set_memory_ro(unsigned long addr, int numpages)
465 return change_page_attr_clear(addr, numpages, __pgprot(_PAGE_RW));
468 int set_memory_rw(unsigned long addr, int numpages)
470 return change_page_attr_set(addr, numpages, __pgprot(_PAGE_RW));
473 int set_memory_np(unsigned long addr, int numpages)
475 return change_page_attr_clear(addr, numpages, __pgprot(_PAGE_PRESENT));
478 int set_pages_uc(struct page *page, int numpages)
480 unsigned long addr = (unsigned long)page_address(page);
482 return set_memory_uc(addr, numpages);
484 EXPORT_SYMBOL(set_pages_uc);
486 int set_pages_wb(struct page *page, int numpages)
488 unsigned long addr = (unsigned long)page_address(page);
490 return set_memory_wb(addr, numpages);
492 EXPORT_SYMBOL(set_pages_wb);
494 int set_pages_x(struct page *page, int numpages)
496 unsigned long addr = (unsigned long)page_address(page);
498 return set_memory_x(addr, numpages);
500 EXPORT_SYMBOL(set_pages_x);
502 int set_pages_nx(struct page *page, int numpages)
504 unsigned long addr = (unsigned long)page_address(page);
506 return set_memory_nx(addr, numpages);
508 EXPORT_SYMBOL(set_pages_nx);
510 int set_pages_ro(struct page *page, int numpages)
512 unsigned long addr = (unsigned long)page_address(page);
514 return set_memory_ro(addr, numpages);
517 int set_pages_rw(struct page *page, int numpages)
519 unsigned long addr = (unsigned long)page_address(page);
521 return set_memory_rw(addr, numpages);
525 #if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_CPA_DEBUG)
526 static inline int __change_page_attr_set(unsigned long addr, int numpages,
529 return __change_page_attr_set_clr(addr, numpages, mask, __pgprot(0));
532 static inline int __change_page_attr_clear(unsigned long addr, int numpages,
535 return __change_page_attr_set_clr(addr, numpages, __pgprot(0), mask);
539 #ifdef CONFIG_DEBUG_PAGEALLOC
541 static int __set_pages_p(struct page *page, int numpages)
543 unsigned long addr = (unsigned long)page_address(page);
545 return __change_page_attr_set(addr, numpages,
546 __pgprot(_PAGE_PRESENT | _PAGE_RW));
549 static int __set_pages_np(struct page *page, int numpages)
551 unsigned long addr = (unsigned long)page_address(page);
553 return __change_page_attr_clear(addr, numpages,
554 __pgprot(_PAGE_PRESENT));
557 void kernel_map_pages(struct page *page, int numpages, int enable)
559 if (PageHighMem(page))
562 debug_check_no_locks_freed(page_address(page),
563 numpages * PAGE_SIZE);
567 * If page allocator is not up yet then do not call c_p_a():
569 if (!debug_pagealloc_enabled)
573 * The return value is ignored - the calls cannot fail,
574 * large pages are disabled at boot time:
577 __set_pages_p(page, numpages);
579 __set_pages_np(page, numpages);
582 * We should perform an IPI and flush all tlbs,
583 * but that can deadlock->flush only current cpu:
590 * The testcases use internal knowledge of the implementation that shouldn't
591 * be exposed to the rest of the kernel. Include these directly here.
593 #ifdef CONFIG_CPA_DEBUG
594 #include "pageattr-test.c"