xref: /linux/arch/powerpc/mm/pgtable_32.c (revision b85d45947951d23cb22d90caecf4c1eb81342c96)
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 
38 #include "mmu_decl.h"
39 
40 unsigned long ioremap_base;
41 unsigned long ioremap_bot;
42 EXPORT_SYMBOL(ioremap_bot);	/* aka VMALLOC_END */
43 
44 #ifdef CONFIG_6xx
45 #define HAVE_BATS	1
46 #endif
47 
48 #if defined(CONFIG_FSL_BOOKE)
49 #define HAVE_TLBCAM	1
50 #endif
51 
52 extern char etext[], _stext[];
53 
54 #ifdef HAVE_BATS
55 extern phys_addr_t v_mapped_by_bats(unsigned long va);
56 extern unsigned long p_mapped_by_bats(phys_addr_t pa);
57 #else /* !HAVE_BATS */
58 #define v_mapped_by_bats(x)	(0UL)
59 #define p_mapped_by_bats(x)	(0UL)
60 #endif /* HAVE_BATS */
61 
62 #ifdef HAVE_TLBCAM
63 extern phys_addr_t v_mapped_by_tlbcam(unsigned long va);
64 extern unsigned long p_mapped_by_tlbcam(phys_addr_t pa);
65 #else /* !HAVE_TLBCAM */
66 #define v_mapped_by_tlbcam(x)	(0UL)
67 #define p_mapped_by_tlbcam(x)	(0UL)
68 #endif /* HAVE_TLBCAM */
69 
70 #define PGDIR_ORDER	(32 + PGD_T_LOG2 - PGDIR_SHIFT)
71 
72 #ifndef CONFIG_PPC_4K_PAGES
73 static struct kmem_cache *pgtable_cache;
74 
75 void pgtable_cache_init(void)
76 {
77 	pgtable_cache = kmem_cache_create("PGDIR cache", 1 << PGDIR_ORDER,
78 					  1 << PGDIR_ORDER, 0, NULL);
79 	if (pgtable_cache == NULL)
80 		panic("Couldn't allocate pgtable caches");
81 }
82 #endif
83 
84 pgd_t *pgd_alloc(struct mm_struct *mm)
85 {
86 	pgd_t *ret;
87 
88 	/* pgdir take page or two with 4K pages and a page fraction otherwise */
89 #ifndef CONFIG_PPC_4K_PAGES
90 	ret = kmem_cache_alloc(pgtable_cache, GFP_KERNEL | __GFP_ZERO);
91 #else
92 	ret = (pgd_t *)__get_free_pages(GFP_KERNEL|__GFP_ZERO,
93 			PGDIR_ORDER - PAGE_SHIFT);
94 #endif
95 	return ret;
96 }
97 
98 void pgd_free(struct mm_struct *mm, pgd_t *pgd)
99 {
100 #ifndef CONFIG_PPC_4K_PAGES
101 	kmem_cache_free(pgtable_cache, (void *)pgd);
102 #else
103 	free_pages((unsigned long)pgd, PGDIR_ORDER - PAGE_SHIFT);
104 #endif
105 }
106 
107 __init_refok pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
108 {
109 	pte_t *pte;
110 
111 	if (slab_is_available()) {
112 		pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
113 	} else {
114 		pte = __va(memblock_alloc(PAGE_SIZE, PAGE_SIZE));
115 		if (pte)
116 			clear_page(pte);
117 	}
118 	return pte;
119 }
120 
121 pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
122 {
123 	struct page *ptepage;
124 
125 	gfp_t flags = GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO;
126 
127 	ptepage = alloc_pages(flags, 0);
128 	if (!ptepage)
129 		return NULL;
130 	if (!pgtable_page_ctor(ptepage)) {
131 		__free_page(ptepage);
132 		return NULL;
133 	}
134 	return ptepage;
135 }
136 
137 void __iomem *
138 ioremap(phys_addr_t addr, unsigned long size)
139 {
140 	return __ioremap_caller(addr, size, _PAGE_NO_CACHE | _PAGE_GUARDED,
141 				__builtin_return_address(0));
142 }
143 EXPORT_SYMBOL(ioremap);
144 
145 void __iomem *
146 ioremap_wc(phys_addr_t addr, unsigned long size)
147 {
148 	return __ioremap_caller(addr, size, _PAGE_NO_CACHE,
149 				__builtin_return_address(0));
150 }
151 EXPORT_SYMBOL(ioremap_wc);
152 
153 void __iomem *
154 ioremap_prot(phys_addr_t addr, unsigned long size, unsigned long flags)
155 {
156 	/* writeable implies dirty for kernel addresses */
157 	if ((flags & (_PAGE_RW | _PAGE_RO)) != _PAGE_RO)
158 		flags |= _PAGE_DIRTY | _PAGE_HWWRITE;
159 
160 	/* we don't want to let _PAGE_USER and _PAGE_EXEC leak out */
161 	flags &= ~(_PAGE_USER | _PAGE_EXEC);
162 
163 #ifdef _PAGE_BAP_SR
164 	/* _PAGE_USER contains _PAGE_BAP_SR on BookE using the new PTE format
165 	 * which means that we just cleared supervisor access... oops ;-) This
166 	 * restores it
167 	 */
168 	flags |= _PAGE_BAP_SR;
169 #endif
170 
171 	return __ioremap_caller(addr, size, flags, __builtin_return_address(0));
172 }
173 EXPORT_SYMBOL(ioremap_prot);
174 
175 void __iomem *
176 __ioremap(phys_addr_t addr, unsigned long size, unsigned long flags)
177 {
178 	return __ioremap_caller(addr, size, flags, __builtin_return_address(0));
179 }
180 
181 void __iomem *
182 __ioremap_caller(phys_addr_t addr, unsigned long size, unsigned long flags,
183 		 void *caller)
184 {
185 	unsigned long v, i;
186 	phys_addr_t p;
187 	int err;
188 
189 	/* Make sure we have the base flags */
190 	if ((flags & _PAGE_PRESENT) == 0)
191 		flags |= pgprot_val(PAGE_KERNEL);
192 
193 	/* Non-cacheable page cannot be coherent */
194 	if (flags & _PAGE_NO_CACHE)
195 		flags &= ~_PAGE_COHERENT;
196 
197 	/*
198 	 * Choose an address to map it to.
199 	 * Once the vmalloc system is running, we use it.
200 	 * Before then, we use space going down from ioremap_base
201 	 * (ioremap_bot records where we're up to).
202 	 */
203 	p = addr & PAGE_MASK;
204 	size = PAGE_ALIGN(addr + size) - p;
205 
206 	/*
207 	 * If the address lies within the first 16 MB, assume it's in ISA
208 	 * memory space
209 	 */
210 	if (p < 16*1024*1024)
211 		p += _ISA_MEM_BASE;
212 
213 #ifndef CONFIG_CRASH_DUMP
214 	/*
215 	 * Don't allow anybody to remap normal RAM that we're using.
216 	 * mem_init() sets high_memory so only do the check after that.
217 	 */
218 	if (slab_is_available() && (p < virt_to_phys(high_memory)) &&
219 	    !(__allow_ioremap_reserved && memblock_is_region_reserved(p, size))) {
220 		printk("__ioremap(): phys addr 0x%llx is RAM lr %ps\n",
221 		       (unsigned long long)p, __builtin_return_address(0));
222 		return NULL;
223 	}
224 #endif
225 
226 	if (size == 0)
227 		return NULL;
228 
229 	/*
230 	 * Is it already mapped?  Perhaps overlapped by a previous
231 	 * BAT mapping.  If the whole area is mapped then we're done,
232 	 * otherwise remap it since we want to keep the virt addrs for
233 	 * each request contiguous.
234 	 *
235 	 * We make the assumption here that if the bottom and top
236 	 * of the range we want are mapped then it's mapped to the
237 	 * same virt address (and this is contiguous).
238 	 *  -- Cort
239 	 */
240 	if ((v = p_mapped_by_bats(p)) /*&& p_mapped_by_bats(p+size-1)*/ )
241 		goto out;
242 
243 	if ((v = p_mapped_by_tlbcam(p)))
244 		goto out;
245 
246 	if (slab_is_available()) {
247 		struct vm_struct *area;
248 		area = get_vm_area_caller(size, VM_IOREMAP, caller);
249 		if (area == 0)
250 			return NULL;
251 		area->phys_addr = p;
252 		v = (unsigned long) area->addr;
253 	} else {
254 		v = (ioremap_bot -= size);
255 	}
256 
257 	/*
258 	 * Should check if it is a candidate for a BAT mapping
259 	 */
260 
261 	err = 0;
262 	for (i = 0; i < size && err == 0; i += PAGE_SIZE)
263 		err = map_page(v+i, p+i, flags);
264 	if (err) {
265 		if (slab_is_available())
266 			vunmap((void *)v);
267 		return NULL;
268 	}
269 
270 out:
271 	return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK));
272 }
273 EXPORT_SYMBOL(__ioremap);
274 
275 void iounmap(volatile void __iomem *addr)
276 {
277 	/*
278 	 * If mapped by BATs then there is nothing to do.
279 	 * Calling vfree() generates a benign warning.
280 	 */
281 	if (v_mapped_by_bats((unsigned long)addr)) return;
282 
283 	if (addr > high_memory && (unsigned long) addr < ioremap_bot)
284 		vunmap((void *) (PAGE_MASK & (unsigned long)addr));
285 }
286 EXPORT_SYMBOL(iounmap);
287 
288 int map_page(unsigned long va, phys_addr_t pa, int flags)
289 {
290 	pmd_t *pd;
291 	pte_t *pg;
292 	int err = -ENOMEM;
293 
294 	/* Use upper 10 bits of VA to index the first level map */
295 	pd = pmd_offset(pud_offset(pgd_offset_k(va), va), va);
296 	/* Use middle 10 bits of VA to index the second-level map */
297 	pg = pte_alloc_kernel(pd, va);
298 	if (pg != 0) {
299 		err = 0;
300 		/* The PTE should never be already set nor present in the
301 		 * hash table
302 		 */
303 		BUG_ON((pte_val(*pg) & (_PAGE_PRESENT | _PAGE_HASHPTE)) &&
304 		       flags);
305 		set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT,
306 						     __pgprot(flags)));
307 	}
308 	smp_wmb();
309 	return err;
310 }
311 
312 /*
313  * Map in a chunk of physical memory starting at start.
314  */
315 void __init __mapin_ram_chunk(unsigned long offset, unsigned long top)
316 {
317 	unsigned long v, s, f;
318 	phys_addr_t p;
319 	int ktext;
320 
321 	s = offset;
322 	v = PAGE_OFFSET + s;
323 	p = memstart_addr + s;
324 	for (; s < top; s += PAGE_SIZE) {
325 		ktext = ((char *) v >= _stext && (char *) v < etext);
326 		f = ktext ? pgprot_val(PAGE_KERNEL_TEXT) : pgprot_val(PAGE_KERNEL);
327 		map_page(v, p, f);
328 #ifdef CONFIG_PPC_STD_MMU_32
329 		if (ktext)
330 			hash_preload(&init_mm, v, 0, 0x300);
331 #endif
332 		v += PAGE_SIZE;
333 		p += PAGE_SIZE;
334 	}
335 }
336 
337 void __init mapin_ram(void)
338 {
339 	unsigned long s, top;
340 
341 #ifndef CONFIG_WII
342 	top = total_lowmem;
343 	s = mmu_mapin_ram(top);
344 	__mapin_ram_chunk(s, top);
345 #else
346 	if (!wii_hole_size) {
347 		s = mmu_mapin_ram(total_lowmem);
348 		__mapin_ram_chunk(s, total_lowmem);
349 	} else {
350 		top = wii_hole_start;
351 		s = mmu_mapin_ram(top);
352 		__mapin_ram_chunk(s, top);
353 
354 		top = memblock_end_of_DRAM();
355 		s = wii_mmu_mapin_mem2(top);
356 		__mapin_ram_chunk(s, top);
357 	}
358 #endif
359 }
360 
361 /* Scan the real Linux page tables and return a PTE pointer for
362  * a virtual address in a context.
363  * Returns true (1) if PTE was found, zero otherwise.  The pointer to
364  * the PTE pointer is unmodified if PTE is not found.
365  */
366 int
367 get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep, pmd_t **pmdp)
368 {
369         pgd_t	*pgd;
370 	pud_t	*pud;
371         pmd_t	*pmd;
372         pte_t	*pte;
373         int     retval = 0;
374 
375         pgd = pgd_offset(mm, addr & PAGE_MASK);
376         if (pgd) {
377 		pud = pud_offset(pgd, addr & PAGE_MASK);
378 		if (pud && pud_present(*pud)) {
379 			pmd = pmd_offset(pud, addr & PAGE_MASK);
380 			if (pmd_present(*pmd)) {
381 				pte = pte_offset_map(pmd, addr & PAGE_MASK);
382 				if (pte) {
383 					retval = 1;
384 					*ptep = pte;
385 					if (pmdp)
386 						*pmdp = pmd;
387 					/* XXX caller needs to do pte_unmap, yuck */
388 				}
389 			}
390 		}
391         }
392         return(retval);
393 }
394 
395 #ifdef CONFIG_DEBUG_PAGEALLOC
396 
397 static int __change_page_attr(struct page *page, pgprot_t prot)
398 {
399 	pte_t *kpte;
400 	pmd_t *kpmd;
401 	unsigned long address;
402 
403 	BUG_ON(PageHighMem(page));
404 	address = (unsigned long)page_address(page);
405 
406 	if (v_mapped_by_bats(address) || v_mapped_by_tlbcam(address))
407 		return 0;
408 	if (!get_pteptr(&init_mm, address, &kpte, &kpmd))
409 		return -EINVAL;
410 	__set_pte_at(&init_mm, address, kpte, mk_pte(page, prot), 0);
411 	wmb();
412 	flush_tlb_page(NULL, address);
413 	pte_unmap(kpte);
414 
415 	return 0;
416 }
417 
418 /*
419  * Change the page attributes of an page in the linear mapping.
420  *
421  * THIS CONFLICTS WITH BAT MAPPINGS, DEBUG USE ONLY
422  */
423 static int change_page_attr(struct page *page, int numpages, pgprot_t prot)
424 {
425 	int i, err = 0;
426 	unsigned long flags;
427 
428 	local_irq_save(flags);
429 	for (i = 0; i < numpages; i++, page++) {
430 		err = __change_page_attr(page, prot);
431 		if (err)
432 			break;
433 	}
434 	local_irq_restore(flags);
435 	return err;
436 }
437 
438 
439 void __kernel_map_pages(struct page *page, int numpages, int enable)
440 {
441 	if (PageHighMem(page))
442 		return;
443 
444 	change_page_attr(page, numpages, enable ? PAGE_KERNEL : __pgprot(0));
445 }
446 #endif /* CONFIG_DEBUG_PAGEALLOC */
447 
448 static int fixmaps;
449 
450 void __set_fixmap (enum fixed_addresses idx, phys_addr_t phys, pgprot_t flags)
451 {
452 	unsigned long address = __fix_to_virt(idx);
453 
454 	if (idx >= __end_of_fixed_addresses) {
455 		BUG();
456 		return;
457 	}
458 
459 	map_page(address, phys, pgprot_val(flags));
460 	fixmaps++;
461 }
462 
463 void __this_fixmap_does_not_exist(void)
464 {
465 	WARN_ON(1);
466 }
467