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Linux/arch/powerpc/mm/pgtable_32.c

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  1 /*
  2  * This file contains the routines setting up the linux page tables.
  3  *  -- paulus
  4  *
  5  *  Derived from arch/ppc/mm/init.c:
  6  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
  7  *
  8  *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
  9  *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
 10  *    Copyright (C) 1996 Paul Mackerras
 11  *
 12  *  Derived from "arch/i386/mm/init.c"
 13  *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
 14  *
 15  *  This program is free software; you can redistribute it and/or
 16  *  modify it under the terms of the GNU General Public License
 17  *  as published by the Free Software Foundation; either version
 18  *  2 of the License, or (at your option) any later version.
 19  *
 20  */
 21 
 22 #include <linux/kernel.h>
 23 #include <linux/module.h>
 24 #include <linux/types.h>
 25 #include <linux/mm.h>
 26 #include <linux/vmalloc.h>
 27 #include <linux/init.h>
 28 #include <linux/highmem.h>
 29 #include <linux/memblock.h>
 30 #include <linux/slab.h>
 31 
 32 #include <asm/pgtable.h>
 33 #include <asm/pgalloc.h>
 34 #include <asm/fixmap.h>
 35 #include <asm/io.h>
 36 #include <asm/setup.h>
 37 #include <asm/sections.h>
 38 
 39 #include "mmu_decl.h"
 40 
 41 unsigned long ioremap_bot;
 42 EXPORT_SYMBOL(ioremap_bot);     /* aka VMALLOC_END */
 43 
 44 extern char etext[], _stext[], _sinittext[], _einittext[];
 45 
 46 __ref pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
 47 {
 48         pte_t *pte;
 49 
 50         if (slab_is_available()) {
 51                 pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_ZERO);
 52         } else {
 53                 pte = __va(memblock_alloc(PAGE_SIZE, PAGE_SIZE));
 54                 if (pte)
 55                         clear_page(pte);
 56         }
 57         return pte;
 58 }
 59 
 60 pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
 61 {
 62         struct page *ptepage;
 63 
 64         gfp_t flags = GFP_KERNEL | __GFP_ZERO | __GFP_ACCOUNT;
 65 
 66         ptepage = alloc_pages(flags, 0);
 67         if (!ptepage)
 68                 return NULL;
 69         if (!pgtable_page_ctor(ptepage)) {
 70                 __free_page(ptepage);
 71                 return NULL;
 72         }
 73         return ptepage;
 74 }
 75 
 76 void __iomem *
 77 ioremap(phys_addr_t addr, unsigned long size)
 78 {
 79         return __ioremap_caller(addr, size, _PAGE_NO_CACHE | _PAGE_GUARDED,
 80                                 __builtin_return_address(0));
 81 }
 82 EXPORT_SYMBOL(ioremap);
 83 
 84 void __iomem *
 85 ioremap_wc(phys_addr_t addr, unsigned long size)
 86 {
 87         return __ioremap_caller(addr, size, _PAGE_NO_CACHE,
 88                                 __builtin_return_address(0));
 89 }
 90 EXPORT_SYMBOL(ioremap_wc);
 91 
 92 void __iomem *
 93 ioremap_prot(phys_addr_t addr, unsigned long size, unsigned long flags)
 94 {
 95         /* writeable implies dirty for kernel addresses */
 96         if ((flags & (_PAGE_RW | _PAGE_RO)) != _PAGE_RO)
 97                 flags |= _PAGE_DIRTY | _PAGE_HWWRITE;
 98 
 99         /* we don't want to let _PAGE_USER and _PAGE_EXEC leak out */
100         flags &= ~(_PAGE_USER | _PAGE_EXEC);
101         flags |= _PAGE_PRIVILEGED;
102 
103         return __ioremap_caller(addr, size, flags, __builtin_return_address(0));
104 }
105 EXPORT_SYMBOL(ioremap_prot);
106 
107 void __iomem *
108 __ioremap(phys_addr_t addr, unsigned long size, unsigned long flags)
109 {
110         return __ioremap_caller(addr, size, flags, __builtin_return_address(0));
111 }
112 
113 void __iomem *
114 __ioremap_caller(phys_addr_t addr, unsigned long size, unsigned long flags,
115                  void *caller)
116 {
117         unsigned long v, i;
118         phys_addr_t p;
119         int err;
120 
121         /* Make sure we have the base flags */
122         if ((flags & _PAGE_PRESENT) == 0)
123                 flags |= pgprot_val(PAGE_KERNEL);
124 
125         /* Non-cacheable page cannot be coherent */
126         if (flags & _PAGE_NO_CACHE)
127                 flags &= ~_PAGE_COHERENT;
128 
129         /*
130          * Choose an address to map it to.
131          * Once the vmalloc system is running, we use it.
132          * Before then, we use space going down from IOREMAP_TOP
133          * (ioremap_bot records where we're up to).
134          */
135         p = addr & PAGE_MASK;
136         size = PAGE_ALIGN(addr + size) - p;
137 
138         /*
139          * If the address lies within the first 16 MB, assume it's in ISA
140          * memory space
141          */
142         if (p < 16*1024*1024)
143                 p += _ISA_MEM_BASE;
144 
145 #ifndef CONFIG_CRASH_DUMP
146         /*
147          * Don't allow anybody to remap normal RAM that we're using.
148          * mem_init() sets high_memory so only do the check after that.
149          */
150         if (slab_is_available() && (p < virt_to_phys(high_memory)) &&
151             page_is_ram(__phys_to_pfn(p))) {
152                 printk("__ioremap(): phys addr 0x%llx is RAM lr %ps\n",
153                        (unsigned long long)p, __builtin_return_address(0));
154                 return NULL;
155         }
156 #endif
157 
158         if (size == 0)
159                 return NULL;
160 
161         /*
162          * Is it already mapped?  Perhaps overlapped by a previous
163          * mapping.
164          */
165         v = p_block_mapped(p);
166         if (v)
167                 goto out;
168 
169         if (slab_is_available()) {
170                 struct vm_struct *area;
171                 area = get_vm_area_caller(size, VM_IOREMAP, caller);
172                 if (area == 0)
173                         return NULL;
174                 area->phys_addr = p;
175                 v = (unsigned long) area->addr;
176         } else {
177                 v = (ioremap_bot -= size);
178         }
179 
180         /*
181          * Should check if it is a candidate for a BAT mapping
182          */
183 
184         err = 0;
185         for (i = 0; i < size && err == 0; i += PAGE_SIZE)
186                 err = map_kernel_page(v+i, p+i, flags);
187         if (err) {
188                 if (slab_is_available())
189                         vunmap((void *)v);
190                 return NULL;
191         }
192 
193 out:
194         return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK));
195 }
196 EXPORT_SYMBOL(__ioremap);
197 
198 void iounmap(volatile void __iomem *addr)
199 {
200         /*
201          * If mapped by BATs then there is nothing to do.
202          * Calling vfree() generates a benign warning.
203          */
204         if (v_block_mapped((unsigned long)addr))
205                 return;
206 
207         if (addr > high_memory && (unsigned long) addr < ioremap_bot)
208                 vunmap((void *) (PAGE_MASK & (unsigned long)addr));
209 }
210 EXPORT_SYMBOL(iounmap);
211 
212 int map_kernel_page(unsigned long va, phys_addr_t pa, int flags)
213 {
214         pmd_t *pd;
215         pte_t *pg;
216         int err = -ENOMEM;
217 
218         /* Use upper 10 bits of VA to index the first level map */
219         pd = pmd_offset(pud_offset(pgd_offset_k(va), va), va);
220         /* Use middle 10 bits of VA to index the second-level map */
221         pg = pte_alloc_kernel(pd, va);
222         if (pg != 0) {
223                 err = 0;
224                 /* The PTE should never be already set nor present in the
225                  * hash table
226                  */
227                 BUG_ON((pte_val(*pg) & (_PAGE_PRESENT | _PAGE_HASHPTE)) &&
228                        flags);
229                 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT,
230                                                      __pgprot(flags)));
231         }
232         smp_wmb();
233         return err;
234 }
235 
236 /*
237  * Map in a chunk of physical memory starting at start.
238  */
239 static void __init __mapin_ram_chunk(unsigned long offset, unsigned long top)
240 {
241         unsigned long v, s, f;
242         phys_addr_t p;
243         int ktext;
244 
245         s = offset;
246         v = PAGE_OFFSET + s;
247         p = memstart_addr + s;
248         for (; s < top; s += PAGE_SIZE) {
249                 ktext = ((char *)v >= _stext && (char *)v < etext) ||
250                         ((char *)v >= _sinittext && (char *)v < _einittext);
251                 f = ktext ? pgprot_val(PAGE_KERNEL_TEXT) : pgprot_val(PAGE_KERNEL);
252                 map_kernel_page(v, p, f);
253 #ifdef CONFIG_PPC_STD_MMU_32
254                 if (ktext)
255                         hash_preload(&init_mm, v, 0, 0x300);
256 #endif
257                 v += PAGE_SIZE;
258                 p += PAGE_SIZE;
259         }
260 }
261 
262 void __init mapin_ram(void)
263 {
264         unsigned long s, top;
265 
266 #ifndef CONFIG_WII
267         top = total_lowmem;
268         s = mmu_mapin_ram(top);
269         __mapin_ram_chunk(s, top);
270 #else
271         if (!wii_hole_size) {
272                 s = mmu_mapin_ram(total_lowmem);
273                 __mapin_ram_chunk(s, total_lowmem);
274         } else {
275                 top = wii_hole_start;
276                 s = mmu_mapin_ram(top);
277                 __mapin_ram_chunk(s, top);
278 
279                 top = memblock_end_of_DRAM();
280                 s = wii_mmu_mapin_mem2(top);
281                 __mapin_ram_chunk(s, top);
282         }
283 #endif
284 }
285 
286 /* Scan the real Linux page tables and return a PTE pointer for
287  * a virtual address in a context.
288  * Returns true (1) if PTE was found, zero otherwise.  The pointer to
289  * the PTE pointer is unmodified if PTE is not found.
290  */
291 static int
292 get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep, pmd_t **pmdp)
293 {
294         pgd_t   *pgd;
295         pud_t   *pud;
296         pmd_t   *pmd;
297         pte_t   *pte;
298         int     retval = 0;
299 
300         pgd = pgd_offset(mm, addr & PAGE_MASK);
301         if (pgd) {
302                 pud = pud_offset(pgd, addr & PAGE_MASK);
303                 if (pud && pud_present(*pud)) {
304                         pmd = pmd_offset(pud, addr & PAGE_MASK);
305                         if (pmd_present(*pmd)) {
306                                 pte = pte_offset_map(pmd, addr & PAGE_MASK);
307                                 if (pte) {
308                                         retval = 1;
309                                         *ptep = pte;
310                                         if (pmdp)
311                                                 *pmdp = pmd;
312                                         /* XXX caller needs to do pte_unmap, yuck */
313                                 }
314                         }
315                 }
316         }
317         return(retval);
318 }
319 
320 static int __change_page_attr_noflush(struct page *page, pgprot_t prot)
321 {
322         pte_t *kpte;
323         pmd_t *kpmd;
324         unsigned long address;
325 
326         BUG_ON(PageHighMem(page));
327         address = (unsigned long)page_address(page);
328 
329         if (v_block_mapped(address))
330                 return 0;
331         if (!get_pteptr(&init_mm, address, &kpte, &kpmd))
332                 return -EINVAL;
333         __set_pte_at(&init_mm, address, kpte, mk_pte(page, prot), 0);
334         pte_unmap(kpte);
335 
336         return 0;
337 }
338 
339 /*
340  * Change the page attributes of an page in the linear mapping.
341  *
342  * THIS DOES NOTHING WITH BAT MAPPINGS, DEBUG USE ONLY
343  */
344 static int change_page_attr(struct page *page, int numpages, pgprot_t prot)
345 {
346         int i, err = 0;
347         unsigned long flags;
348         struct page *start = page;
349 
350         local_irq_save(flags);
351         for (i = 0; i < numpages; i++, page++) {
352                 err = __change_page_attr_noflush(page, prot);
353                 if (err)
354                         break;
355         }
356         wmb();
357         local_irq_restore(flags);
358         flush_tlb_kernel_range((unsigned long)page_address(start),
359                                (unsigned long)page_address(page));
360         return err;
361 }
362 
363 void mark_initmem_nx(void)
364 {
365         struct page *page = virt_to_page(_sinittext);
366         unsigned long numpages = PFN_UP((unsigned long)_einittext) -
367                                  PFN_DOWN((unsigned long)_sinittext);
368 
369         change_page_attr(page, numpages, PAGE_KERNEL);
370 }
371 
372 #ifdef CONFIG_STRICT_KERNEL_RWX
373 void mark_rodata_ro(void)
374 {
375         struct page *page;
376         unsigned long numpages;
377 
378         page = virt_to_page(_stext);
379         numpages = PFN_UP((unsigned long)_etext) -
380                    PFN_DOWN((unsigned long)_stext);
381 
382         change_page_attr(page, numpages, PAGE_KERNEL_ROX);
383         /*
384          * mark .rodata as read only. Use __init_begin rather than __end_rodata
385          * to cover NOTES and EXCEPTION_TABLE.
386          */
387         page = virt_to_page(__start_rodata);
388         numpages = PFN_UP((unsigned long)__init_begin) -
389                    PFN_DOWN((unsigned long)__start_rodata);
390 
391         change_page_attr(page, numpages, PAGE_KERNEL_RO);
392 }
393 #endif
394 
395 #ifdef CONFIG_DEBUG_PAGEALLOC
396 void __kernel_map_pages(struct page *page, int numpages, int enable)
397 {
398         if (PageHighMem(page))
399                 return;
400 
401         change_page_attr(page, numpages, enable ? PAGE_KERNEL : __pgprot(0));
402 }
403 #endif /* CONFIG_DEBUG_PAGEALLOC */
404 

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