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 *  Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
12 *
13 *  Derived from "arch/i386/mm/init.c"
14 *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
15 *
16 *  This program is free software; you can redistribute it and/or
17 *  modify it under the terms of the GNU General Public License
18 *  as published by the Free Software Foundation; either version
19 *  2 of the License, or (at your option) any later version.
20 *
21 */
22
23#include <linux/kernel.h>
24#include <linux/module.h>
25#include <linux/types.h>
26#include <linux/mm.h>
27#include <linux/vmalloc.h>
28#include <linux/init.h>
29#include <linux/highmem.h>
30
31#include <asm/pgtable.h>
32#include <asm/pgalloc.h>
33#include <asm/io.h>
34
35#include "mmu_decl.h"
36
37unsigned long ioremap_base;
38unsigned long ioremap_bot;
39EXPORT_SYMBOL(ioremap_bot);	/* aka VMALLOC_END */
40int io_bat_index;
41
42#if defined(CONFIG_6xx) || defined(CONFIG_POWER3)
43#define HAVE_BATS	1
44#endif
45
46#if defined(CONFIG_FSL_BOOKE)
47#define HAVE_TLBCAM	1
48#endif
49
50extern char etext[], _stext[];
51
52#ifdef CONFIG_SMP
53extern void hash_page_sync(void);
54#endif
55
56#ifdef HAVE_BATS
57extern unsigned long v_mapped_by_bats(unsigned long va);
58extern unsigned long p_mapped_by_bats(unsigned long pa);
59void setbat(int index, unsigned long virt, unsigned long phys,
60	    unsigned int size, int flags);
61
62#else /* !HAVE_BATS */
63#define v_mapped_by_bats(x)	(0UL)
64#define p_mapped_by_bats(x)	(0UL)
65#endif /* HAVE_BATS */
66
67#ifdef HAVE_TLBCAM
68extern unsigned int tlbcam_index;
69extern unsigned long v_mapped_by_tlbcam(unsigned long va);
70extern unsigned long p_mapped_by_tlbcam(unsigned long pa);
71#else /* !HAVE_TLBCAM */
72#define v_mapped_by_tlbcam(x)	(0UL)
73#define p_mapped_by_tlbcam(x)	(0UL)
74#endif /* HAVE_TLBCAM */
75
76#ifdef CONFIG_PTE_64BIT
77/* 44x uses an 8kB pgdir because it has 8-byte Linux PTEs. */
78#define PGDIR_ORDER	1
79#else
80#define PGDIR_ORDER	0
81#endif
82
83pgd_t *pgd_alloc(struct mm_struct *mm)
84{
85	pgd_t *ret;
86
87	ret = (pgd_t *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, PGDIR_ORDER);
88	return ret;
89}
90
91void pgd_free(pgd_t *pgd)
92{
93	free_pages((unsigned long)pgd, PGDIR_ORDER);
94}
95
96__init_refok pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
97{
98	pte_t *pte;
99	extern int mem_init_done;
100	extern void *early_get_page(void);
101
102	if (mem_init_done) {
103		pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
104	} else {
105		pte = (pte_t *)early_get_page();
106		if (pte)
107			clear_page(pte);
108	}
109	return pte;
110}
111
112struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
113{
114	struct page *ptepage;
115
116#ifdef CONFIG_HIGHPTE
117	gfp_t flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_REPEAT;
118#else
119	gfp_t flags = GFP_KERNEL | __GFP_REPEAT;
120#endif
121
122	ptepage = alloc_pages(flags, 0);
123	if (ptepage)
124		clear_highpage(ptepage);
125	return ptepage;
126}
127
128void pte_free_kernel(pte_t *pte)
129{
130#ifdef CONFIG_SMP
131	hash_page_sync();
132#endif
133	free_page((unsigned long)pte);
134}
135
136void pte_free(struct page *ptepage)
137{
138#ifdef CONFIG_SMP
139	hash_page_sync();
140#endif
141	__free_page(ptepage);
142}
143
144void __iomem *
145ioremap(phys_addr_t addr, unsigned long size)
146{
147	return __ioremap(addr, size, _PAGE_NO_CACHE);
148}
149EXPORT_SYMBOL(ioremap);
150
151void __iomem *
152ioremap_flags(phys_addr_t addr, unsigned long size, unsigned long flags)
153{
154	return __ioremap(addr, size, flags);
155}
156EXPORT_SYMBOL(ioremap_flags);
157
158void __iomem *
159__ioremap(phys_addr_t addr, unsigned long size, unsigned long flags)
160{
161	unsigned long v, i;
162	phys_addr_t p;
163	int err;
164
165	/*
166	 * Choose an address to map it to.
167	 * Once the vmalloc system is running, we use it.
168	 * Before then, we use space going down from ioremap_base
169	 * (ioremap_bot records where we're up to).
170	 */
171	p = addr & PAGE_MASK;
172	size = PAGE_ALIGN(addr + size) - p;
173
174	/*
175	 * If the address lies within the first 16 MB, assume it's in ISA
176	 * memory space
177	 */
178	if (p < 16*1024*1024)
179		p += _ISA_MEM_BASE;
180
181	/*
182	 * Don't allow anybody to remap normal RAM that we're using.
183	 * mem_init() sets high_memory so only do the check after that.
184	 */
185	if (mem_init_done && (p < virt_to_phys(high_memory))) {
186		printk("__ioremap(): phys addr 0x%llx is RAM lr %p\n",
187		       (unsigned long long)p, __builtin_return_address(0));
188		return NULL;
189	}
190
191	if (size == 0)
192		return NULL;
193
194	/*
195	 * Is it already mapped?  Perhaps overlapped by a previous
196	 * BAT mapping.  If the whole area is mapped then we're done,
197	 * otherwise remap it since we want to keep the virt addrs for
198	 * each request contiguous.
199	 *
200	 * We make the assumption here that if the bottom and top
201	 * of the range we want are mapped then it's mapped to the
202	 * same virt address (and this is contiguous).
203	 *  -- Cort
204	 */
205	if ((v = p_mapped_by_bats(p)) /*&& p_mapped_by_bats(p+size-1)*/ )
206		goto out;
207
208	if ((v = p_mapped_by_tlbcam(p)))
209		goto out;
210
211	if (mem_init_done) {
212		struct vm_struct *area;
213		area = get_vm_area(size, VM_IOREMAP);
214		if (area == 0)
215			return NULL;
216		v = (unsigned long) area->addr;
217	} else {
218		v = (ioremap_bot -= size);
219	}
220
221	if ((flags & _PAGE_PRESENT) == 0)
222		flags |= _PAGE_KERNEL;
223	if (flags & _PAGE_NO_CACHE)
224		flags |= _PAGE_GUARDED;
225
226	/*
227	 * Should check if it is a candidate for a BAT mapping
228	 */
229
230	err = 0;
231	for (i = 0; i < size && err == 0; i += PAGE_SIZE)
232		err = map_page(v+i, p+i, flags);
233	if (err) {
234		if (mem_init_done)
235			vunmap((void *)v);
236		return NULL;
237	}
238
239out:
240	return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK));
241}
242EXPORT_SYMBOL(__ioremap);
243
244void iounmap(volatile void __iomem *addr)
245{
246	/*
247	 * If mapped by BATs then there is nothing to do.
248	 * Calling vfree() generates a benign warning.
249	 */
250	if (v_mapped_by_bats((unsigned long)addr)) return;
251
252	if (addr > high_memory && (unsigned long) addr < ioremap_bot)
253		vunmap((void *) (PAGE_MASK & (unsigned long)addr));
254}
255EXPORT_SYMBOL(iounmap);
256
257int map_page(unsigned long va, phys_addr_t pa, int flags)
258{
259	pmd_t *pd;
260	pte_t *pg;
261	int err = -ENOMEM;
262
263	/* Use upper 10 bits of VA to index the first level map */
264	pd = pmd_offset(pud_offset(pgd_offset_k(va), va), va);
265	/* Use middle 10 bits of VA to index the second-level map */
266	pg = pte_alloc_kernel(pd, va);
267	if (pg != 0) {
268		err = 0;
269		/* The PTE should never be already set nor present in the
270		 * hash table
271		 */
272		BUG_ON(pte_val(*pg) & (_PAGE_PRESENT | _PAGE_HASHPTE));
273		set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT,
274						     __pgprot(flags)));
275	}
276	return err;
277}
278
279/*
280 * Map in all of physical memory starting at KERNELBASE.
281 */
282void __init mapin_ram(void)
283{
284	unsigned long v, p, s, f;
285	int ktext;
286
287	s = mmu_mapin_ram();
288	v = KERNELBASE + s;
289	p = PPC_MEMSTART + s;
290	for (; s < total_lowmem; s += PAGE_SIZE) {
291		ktext = ((char *) v >= _stext && (char *) v < etext);
292		f = ktext ?_PAGE_RAM_TEXT : _PAGE_RAM;
293		map_page(v, p, f);
294#ifdef CONFIG_PPC_STD_MMU_32
295		if (ktext)
296			hash_preload(&init_mm, v, 0, 0x300);
297#endif
298		v += PAGE_SIZE;
299		p += PAGE_SIZE;
300	}
301}
302
303/* is x a power of 4? */
304#define is_power_of_4(x)	is_power_of_2(x) && (ffs(x) & 1)
305
306/*
307 * Set up a mapping for a block of I/O.
308 * virt, phys, size must all be page-aligned.
309 * This should only be called before ioremap is called.
310 */
311void __init io_block_mapping(unsigned long virt, phys_addr_t phys,
312			     unsigned int size, int flags)
313{
314	int i;
315
316	if (virt > KERNELBASE && virt < ioremap_bot)
317		ioremap_bot = ioremap_base = virt;
318
319#ifdef HAVE_BATS
320	/*
321	 * Use a BAT for this if possible...
322	 */
323	if (io_bat_index < 2 && is_power_of_2(size)
324	    && (virt & (size - 1)) == 0 && (phys & (size - 1)) == 0) {
325		setbat(io_bat_index, virt, phys, size, flags);
326		++io_bat_index;
327		return;
328	}
329#endif /* HAVE_BATS */
330
331#ifdef HAVE_TLBCAM
332	/*
333	 * Use a CAM for this if possible...
334	 */
335	if (tlbcam_index < num_tlbcam_entries && is_power_of_4(size)
336	    && (virt & (size - 1)) == 0 && (phys & (size - 1)) == 0) {
337		settlbcam(tlbcam_index, virt, phys, size, flags, 0);
338		++tlbcam_index;
339		return;
340	}
341#endif /* HAVE_TLBCAM */
342
343	/* No BATs available, put it in the page tables. */
344	for (i = 0; i < size; i += PAGE_SIZE)
345		map_page(virt + i, phys + i, flags);
346}
347
348/* Scan the real Linux page tables and return a PTE pointer for
349 * a virtual address in a context.
350 * Returns true (1) if PTE was found, zero otherwise.  The pointer to
351 * the PTE pointer is unmodified if PTE is not found.
352 */
353int
354get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep, pmd_t **pmdp)
355{
356        pgd_t	*pgd;
357	pud_t	*pud;
358        pmd_t	*pmd;
359        pte_t	*pte;
360        int     retval = 0;
361
362        pgd = pgd_offset(mm, addr & PAGE_MASK);
363        if (pgd) {
364		pud = pud_offset(pgd, addr & PAGE_MASK);
365		if (pud && pud_present(*pud)) {
366			pmd = pmd_offset(pud, addr & PAGE_MASK);
367			if (pmd_present(*pmd)) {
368				pte = pte_offset_map(pmd, addr & PAGE_MASK);
369				if (pte) {
370					retval = 1;
371					*ptep = pte;
372					if (pmdp)
373						*pmdp = pmd;
374				}
375			}
376		}
377        }
378        return(retval);
379}
380
381/* Find physical address for this virtual address.  Normally used by
382 * I/O functions, but anyone can call it.
383 */
384unsigned long iopa(unsigned long addr)
385{
386	unsigned long pa;
387
388	/* I don't know why this won't work on PMacs or CHRP.  It
389	 * appears there is some bug, or there is some implicit
390	 * mapping done not properly represented by BATs or in page
391	 * tables.......I am actively working on resolving this, but
392	 * can't hold up other stuff.  -- Dan
393	 */
394	pte_t *pte;
395	struct mm_struct *mm;
396
397	/* Check the BATs */
398	pa = v_mapped_by_bats(addr);
399	if (pa)
400		return pa;
401
402	/* Allow mapping of user addresses (within the thread)
403	 * for DMA if necessary.
404	 */
405	if (addr < TASK_SIZE)
406		mm = current->mm;
407	else
408		mm = &init_mm;
409
410	pa = 0;
411	if (get_pteptr(mm, addr, &pte, NULL)) {
412		pa = (pte_val(*pte) & PAGE_MASK) | (addr & ~PAGE_MASK);
413		pte_unmap(pte);
414	}
415
416	return(pa);
417}
418
419/* This is will find the virtual address for a physical one....
420 * Swiped from APUS, could be dangerous :-).
421 * This is only a placeholder until I really find a way to make this
422 * work.  -- Dan
423 */
424unsigned long
425mm_ptov (unsigned long paddr)
426{
427	unsigned long ret;
428	ret = (unsigned long)paddr + KERNELBASE;
429	return ret;
430}
431
432#ifdef CONFIG_DEBUG_PAGEALLOC
433
434static int __change_page_attr(struct page *page, pgprot_t prot)
435{
436	pte_t *kpte;
437	pmd_t *kpmd;
438	unsigned long address;
439
440	BUG_ON(PageHighMem(page));
441	address = (unsigned long)page_address(page);
442
443	if (v_mapped_by_bats(address) || v_mapped_by_tlbcam(address))
444		return 0;
445	if (!get_pteptr(&init_mm, address, &kpte, &kpmd))
446		return -EINVAL;
447	set_pte_at(&init_mm, address, kpte, mk_pte(page, prot));
448	wmb();
449	flush_HPTE(0, address, pmd_val(*kpmd));
450	pte_unmap(kpte);
451
452	return 0;
453}
454
455/*
456 * Change the page attributes of an page in the linear mapping.
457 *
458 * THIS CONFLICTS WITH BAT MAPPINGS, DEBUG USE ONLY
459 */
460static int change_page_attr(struct page *page, int numpages, pgprot_t prot)
461{
462	int i, err = 0;
463	unsigned long flags;
464
465	local_irq_save(flags);
466	for (i = 0; i < numpages; i++, page++) {
467		err = __change_page_attr(page, prot);
468		if (err)
469			break;
470	}
471	local_irq_restore(flags);
472	return err;
473}
474
475
476void kernel_map_pages(struct page *page, int numpages, int enable)
477{
478	if (PageHighMem(page))
479		return;
480
481	change_page_attr(page, numpages, enable ? PAGE_KERNEL : __pgprot(0));
482}
483#endif /* CONFIG_DEBUG_PAGEALLOC */
484