xref: /openbmc/linux/arch/powerpc/mm/pgtable_32.c (revision 6774def6)
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 void setbat(int index, unsigned long virt, phys_addr_t phys,
58 	    unsigned int size, int flags);
59 
60 #else /* !HAVE_BATS */
61 #define v_mapped_by_bats(x)	(0UL)
62 #define p_mapped_by_bats(x)	(0UL)
63 #endif /* HAVE_BATS */
64 
65 #ifdef HAVE_TLBCAM
66 extern unsigned int tlbcam_index;
67 extern phys_addr_t v_mapped_by_tlbcam(unsigned long va);
68 extern unsigned long p_mapped_by_tlbcam(phys_addr_t pa);
69 #else /* !HAVE_TLBCAM */
70 #define v_mapped_by_tlbcam(x)	(0UL)
71 #define p_mapped_by_tlbcam(x)	(0UL)
72 #endif /* HAVE_TLBCAM */
73 
74 #define PGDIR_ORDER	(32 + PGD_T_LOG2 - PGDIR_SHIFT)
75 
76 pgd_t *pgd_alloc(struct mm_struct *mm)
77 {
78 	pgd_t *ret;
79 
80 	/* pgdir take page or two with 4K pages and a page fraction otherwise */
81 #ifndef CONFIG_PPC_4K_PAGES
82 	ret = kzalloc(1 << PGDIR_ORDER, GFP_KERNEL);
83 #else
84 	ret = (pgd_t *)__get_free_pages(GFP_KERNEL|__GFP_ZERO,
85 			PGDIR_ORDER - PAGE_SHIFT);
86 #endif
87 	return ret;
88 }
89 
90 void pgd_free(struct mm_struct *mm, pgd_t *pgd)
91 {
92 #ifndef CONFIG_PPC_4K_PAGES
93 	kfree((void *)pgd);
94 #else
95 	free_pages((unsigned long)pgd, PGDIR_ORDER - PAGE_SHIFT);
96 #endif
97 }
98 
99 __init_refok pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
100 {
101 	pte_t *pte;
102 	extern int mem_init_done;
103 	extern void *early_get_page(void);
104 
105 	if (mem_init_done) {
106 		pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
107 	} else {
108 		pte = (pte_t *)early_get_page();
109 		if (pte)
110 			clear_page(pte);
111 	}
112 	return pte;
113 }
114 
115 pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
116 {
117 	struct page *ptepage;
118 
119 	gfp_t flags = GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO;
120 
121 	ptepage = alloc_pages(flags, 0);
122 	if (!ptepage)
123 		return NULL;
124 	if (!pgtable_page_ctor(ptepage)) {
125 		__free_page(ptepage);
126 		return NULL;
127 	}
128 	return ptepage;
129 }
130 
131 void __iomem *
132 ioremap(phys_addr_t addr, unsigned long size)
133 {
134 	return __ioremap_caller(addr, size, _PAGE_NO_CACHE | _PAGE_GUARDED,
135 				__builtin_return_address(0));
136 }
137 EXPORT_SYMBOL(ioremap);
138 
139 void __iomem *
140 ioremap_wc(phys_addr_t addr, unsigned long size)
141 {
142 	return __ioremap_caller(addr, size, _PAGE_NO_CACHE,
143 				__builtin_return_address(0));
144 }
145 EXPORT_SYMBOL(ioremap_wc);
146 
147 void __iomem *
148 ioremap_prot(phys_addr_t addr, unsigned long size, unsigned long flags)
149 {
150 	/* writeable implies dirty for kernel addresses */
151 	if (flags & _PAGE_RW)
152 		flags |= _PAGE_DIRTY | _PAGE_HWWRITE;
153 
154 	/* we don't want to let _PAGE_USER and _PAGE_EXEC leak out */
155 	flags &= ~(_PAGE_USER | _PAGE_EXEC);
156 
157 #ifdef _PAGE_BAP_SR
158 	/* _PAGE_USER contains _PAGE_BAP_SR on BookE using the new PTE format
159 	 * which means that we just cleared supervisor access... oops ;-) This
160 	 * restores it
161 	 */
162 	flags |= _PAGE_BAP_SR;
163 #endif
164 
165 	return __ioremap_caller(addr, size, flags, __builtin_return_address(0));
166 }
167 EXPORT_SYMBOL(ioremap_prot);
168 
169 void __iomem *
170 __ioremap(phys_addr_t addr, unsigned long size, unsigned long flags)
171 {
172 	return __ioremap_caller(addr, size, flags, __builtin_return_address(0));
173 }
174 
175 void __iomem *
176 __ioremap_caller(phys_addr_t addr, unsigned long size, unsigned long flags,
177 		 void *caller)
178 {
179 	unsigned long v, i;
180 	phys_addr_t p;
181 	int err;
182 
183 	/* Make sure we have the base flags */
184 	if ((flags & _PAGE_PRESENT) == 0)
185 		flags |= PAGE_KERNEL;
186 
187 	/* Non-cacheable page cannot be coherent */
188 	if (flags & _PAGE_NO_CACHE)
189 		flags &= ~_PAGE_COHERENT;
190 
191 	/*
192 	 * Choose an address to map it to.
193 	 * Once the vmalloc system is running, we use it.
194 	 * Before then, we use space going down from ioremap_base
195 	 * (ioremap_bot records where we're up to).
196 	 */
197 	p = addr & PAGE_MASK;
198 	size = PAGE_ALIGN(addr + size) - p;
199 
200 	/*
201 	 * If the address lies within the first 16 MB, assume it's in ISA
202 	 * memory space
203 	 */
204 	if (p < 16*1024*1024)
205 		p += _ISA_MEM_BASE;
206 
207 #ifndef CONFIG_CRASH_DUMP
208 	/*
209 	 * Don't allow anybody to remap normal RAM that we're using.
210 	 * mem_init() sets high_memory so only do the check after that.
211 	 */
212 	if (mem_init_done && (p < virt_to_phys(high_memory)) &&
213 	    !(__allow_ioremap_reserved && memblock_is_region_reserved(p, size))) {
214 		printk("__ioremap(): phys addr 0x%llx is RAM lr %pf\n",
215 		       (unsigned long long)p, __builtin_return_address(0));
216 		return NULL;
217 	}
218 #endif
219 
220 	if (size == 0)
221 		return NULL;
222 
223 	/*
224 	 * Is it already mapped?  Perhaps overlapped by a previous
225 	 * BAT mapping.  If the whole area is mapped then we're done,
226 	 * otherwise remap it since we want to keep the virt addrs for
227 	 * each request contiguous.
228 	 *
229 	 * We make the assumption here that if the bottom and top
230 	 * of the range we want are mapped then it's mapped to the
231 	 * same virt address (and this is contiguous).
232 	 *  -- Cort
233 	 */
234 	if ((v = p_mapped_by_bats(p)) /*&& p_mapped_by_bats(p+size-1)*/ )
235 		goto out;
236 
237 	if ((v = p_mapped_by_tlbcam(p)))
238 		goto out;
239 
240 	if (mem_init_done) {
241 		struct vm_struct *area;
242 		area = get_vm_area_caller(size, VM_IOREMAP, caller);
243 		if (area == 0)
244 			return NULL;
245 		area->phys_addr = p;
246 		v = (unsigned long) area->addr;
247 	} else {
248 		v = (ioremap_bot -= size);
249 	}
250 
251 	/*
252 	 * Should check if it is a candidate for a BAT mapping
253 	 */
254 
255 	err = 0;
256 	for (i = 0; i < size && err == 0; i += PAGE_SIZE)
257 		err = map_page(v+i, p+i, flags);
258 	if (err) {
259 		if (mem_init_done)
260 			vunmap((void *)v);
261 		return NULL;
262 	}
263 
264 out:
265 	return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK));
266 }
267 EXPORT_SYMBOL(__ioremap);
268 
269 void iounmap(volatile void __iomem *addr)
270 {
271 	/*
272 	 * If mapped by BATs then there is nothing to do.
273 	 * Calling vfree() generates a benign warning.
274 	 */
275 	if (v_mapped_by_bats((unsigned long)addr)) return;
276 
277 	if (addr > high_memory && (unsigned long) addr < ioremap_bot)
278 		vunmap((void *) (PAGE_MASK & (unsigned long)addr));
279 }
280 EXPORT_SYMBOL(iounmap);
281 
282 int map_page(unsigned long va, phys_addr_t pa, int flags)
283 {
284 	pmd_t *pd;
285 	pte_t *pg;
286 	int err = -ENOMEM;
287 
288 	/* Use upper 10 bits of VA to index the first level map */
289 	pd = pmd_offset(pud_offset(pgd_offset_k(va), va), va);
290 	/* Use middle 10 bits of VA to index the second-level map */
291 	pg = pte_alloc_kernel(pd, va);
292 	if (pg != 0) {
293 		err = 0;
294 		/* The PTE should never be already set nor present in the
295 		 * hash table
296 		 */
297 		BUG_ON((pte_val(*pg) & (_PAGE_PRESENT | _PAGE_HASHPTE)) &&
298 		       flags);
299 		set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT,
300 						     __pgprot(flags)));
301 	}
302 	smp_wmb();
303 	return err;
304 }
305 
306 /*
307  * Map in a chunk of physical memory starting at start.
308  */
309 void __init __mapin_ram_chunk(unsigned long offset, unsigned long top)
310 {
311 	unsigned long v, s, f;
312 	phys_addr_t p;
313 	int ktext;
314 
315 	s = offset;
316 	v = PAGE_OFFSET + s;
317 	p = memstart_addr + s;
318 	for (; s < top; s += PAGE_SIZE) {
319 		ktext = ((char *) v >= _stext && (char *) v < etext);
320 		f = ktext ? PAGE_KERNEL_TEXT : PAGE_KERNEL;
321 		map_page(v, p, f);
322 #ifdef CONFIG_PPC_STD_MMU_32
323 		if (ktext)
324 			hash_preload(&init_mm, v, 0, 0x300);
325 #endif
326 		v += PAGE_SIZE;
327 		p += PAGE_SIZE;
328 	}
329 }
330 
331 void __init mapin_ram(void)
332 {
333 	unsigned long s, top;
334 
335 #ifndef CONFIG_WII
336 	top = total_lowmem;
337 	s = mmu_mapin_ram(top);
338 	__mapin_ram_chunk(s, top);
339 #else
340 	if (!wii_hole_size) {
341 		s = mmu_mapin_ram(total_lowmem);
342 		__mapin_ram_chunk(s, total_lowmem);
343 	} else {
344 		top = wii_hole_start;
345 		s = mmu_mapin_ram(top);
346 		__mapin_ram_chunk(s, top);
347 
348 		top = memblock_end_of_DRAM();
349 		s = wii_mmu_mapin_mem2(top);
350 		__mapin_ram_chunk(s, top);
351 	}
352 #endif
353 }
354 
355 /* Scan the real Linux page tables and return a PTE pointer for
356  * a virtual address in a context.
357  * Returns true (1) if PTE was found, zero otherwise.  The pointer to
358  * the PTE pointer is unmodified if PTE is not found.
359  */
360 int
361 get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep, pmd_t **pmdp)
362 {
363         pgd_t	*pgd;
364 	pud_t	*pud;
365         pmd_t	*pmd;
366         pte_t	*pte;
367         int     retval = 0;
368 
369         pgd = pgd_offset(mm, addr & PAGE_MASK);
370         if (pgd) {
371 		pud = pud_offset(pgd, addr & PAGE_MASK);
372 		if (pud && pud_present(*pud)) {
373 			pmd = pmd_offset(pud, addr & PAGE_MASK);
374 			if (pmd_present(*pmd)) {
375 				pte = pte_offset_map(pmd, addr & PAGE_MASK);
376 				if (pte) {
377 					retval = 1;
378 					*ptep = pte;
379 					if (pmdp)
380 						*pmdp = pmd;
381 					/* XXX caller needs to do pte_unmap, yuck */
382 				}
383 			}
384 		}
385         }
386         return(retval);
387 }
388 
389 #ifdef CONFIG_DEBUG_PAGEALLOC
390 
391 static int __change_page_attr(struct page *page, pgprot_t prot)
392 {
393 	pte_t *kpte;
394 	pmd_t *kpmd;
395 	unsigned long address;
396 
397 	BUG_ON(PageHighMem(page));
398 	address = (unsigned long)page_address(page);
399 
400 	if (v_mapped_by_bats(address) || v_mapped_by_tlbcam(address))
401 		return 0;
402 	if (!get_pteptr(&init_mm, address, &kpte, &kpmd))
403 		return -EINVAL;
404 	__set_pte_at(&init_mm, address, kpte, mk_pte(page, prot), 0);
405 	wmb();
406 	flush_tlb_page(NULL, address);
407 	pte_unmap(kpte);
408 
409 	return 0;
410 }
411 
412 /*
413  * Change the page attributes of an page in the linear mapping.
414  *
415  * THIS CONFLICTS WITH BAT MAPPINGS, DEBUG USE ONLY
416  */
417 static int change_page_attr(struct page *page, int numpages, pgprot_t prot)
418 {
419 	int i, err = 0;
420 	unsigned long flags;
421 
422 	local_irq_save(flags);
423 	for (i = 0; i < numpages; i++, page++) {
424 		err = __change_page_attr(page, prot);
425 		if (err)
426 			break;
427 	}
428 	local_irq_restore(flags);
429 	return err;
430 }
431 
432 
433 void kernel_map_pages(struct page *page, int numpages, int enable)
434 {
435 	if (PageHighMem(page))
436 		return;
437 
438 	change_page_attr(page, numpages, enable ? PAGE_KERNEL : __pgprot(0));
439 }
440 #endif /* CONFIG_DEBUG_PAGEALLOC */
441 
442 static int fixmaps;
443 
444 void __set_fixmap (enum fixed_addresses idx, phys_addr_t phys, pgprot_t flags)
445 {
446 	unsigned long address = __fix_to_virt(idx);
447 
448 	if (idx >= __end_of_fixed_addresses) {
449 		BUG();
450 		return;
451 	}
452 
453 	map_page(address, phys, pgprot_val(flags));
454 	fixmaps++;
455 }
456 
457 void __this_fixmap_does_not_exist(void)
458 {
459 	WARN_ON(1);
460 }
461