summaryrefslogtreecommitdiff
path: root/arch/microblaze/mm/pgtable.c
blob: 68c26cacd9305f843281c4b0084e84171b506160 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
/*
 *  This file contains the routines setting up the linux page tables.
 *
 * Copyright (C) 2008 Michal Simek
 * Copyright (C) 2008 PetaLogix
 *
 *    Copyright (C) 2007 Xilinx, Inc.  All rights reserved.
 *
 *  Derived from arch/ppc/mm/pgtable.c:
 *    -- paulus
 *
 *  Derived from arch/ppc/mm/init.c:
 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
 *
 *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
 *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
 *    Copyright (C) 1996 Paul Mackerras
 *  Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
 *
 *  Derived from "arch/i386/mm/init.c"
 *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
 *
 *  This file is subject to the terms and conditions of the GNU General
 *  Public License.  See the file COPYING in the main directory of this
 *  archive for more details.
 *
 */

#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/vmalloc.h>
#include <linux/init.h>
#include <linux/mm_types.h>

#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <linux/io.h>
#include <asm/mmu.h>
#include <asm/sections.h>
#include <asm/fixmap.h>

unsigned long ioremap_base;
unsigned long ioremap_bot;
EXPORT_SYMBOL(ioremap_bot);

static void __iomem *__ioremap(phys_addr_t addr, unsigned long size,
		unsigned long flags)
{
	unsigned long v, i;
	phys_addr_t p;
	int err;

	/*
	 * Choose an address to map it to.
	 * Once the vmalloc system is running, we use it.
	 * Before then, we use space going down from ioremap_base
	 * (ioremap_bot records where we're up to).
	 */
	p = addr & PAGE_MASK;
	size = PAGE_ALIGN(addr + size) - p;

	/*
	 * Don't allow anybody to remap normal RAM that we're using.
	 * mem_init() sets high_memory so only do the check after that.
	 *
	 * However, allow remap of rootfs: TBD
	 */

	if (mem_init_done &&
		p >= memory_start && p < virt_to_phys(high_memory) &&
		!(p >= __virt_to_phys((phys_addr_t)__bss_stop) &&
		p < __virt_to_phys((phys_addr_t)__bss_stop))) {
		pr_warn("__ioremap(): phys addr "PTE_FMT" is RAM lr %ps\n",
			(unsigned long)p, __builtin_return_address(0));
		return NULL;
	}

	if (size == 0)
		return NULL;

	/*
	 * Is it already mapped? If the whole area is mapped then we're
	 * done, otherwise remap it since we want to keep the virt addrs for
	 * each request contiguous.
	 *
	 * We make the assumption here that if the bottom and top
	 * of the range we want are mapped then it's mapped to the
	 * same virt address (and this is contiguous).
	 *  -- Cort
	 */

	if (mem_init_done) {
		struct vm_struct *area;
		area = get_vm_area(size, VM_IOREMAP);
		if (area == NULL)
			return NULL;
		v = (unsigned long) area->addr;
	} else {
		v = (ioremap_bot -= size);
	}

	if ((flags & _PAGE_PRESENT) == 0)
		flags |= _PAGE_KERNEL;
	if (flags & _PAGE_NO_CACHE)
		flags |= _PAGE_GUARDED;

	err = 0;
	for (i = 0; i < size && err == 0; i += PAGE_SIZE)
		err = map_page(v + i, p + i, flags);
	if (err) {
		if (mem_init_done)
			vfree((void *)v);
		return NULL;
	}

	return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK));
}

void __iomem *ioremap(phys_addr_t addr, unsigned long size)
{
	return __ioremap(addr, size, _PAGE_NO_CACHE);
}
EXPORT_SYMBOL(ioremap);

void iounmap(volatile void __iomem *addr)
{
	if ((__force void *)addr > high_memory &&
					(unsigned long) addr < ioremap_bot)
		vfree((void *) (PAGE_MASK & (unsigned long) addr));
}
EXPORT_SYMBOL(iounmap);


int map_page(unsigned long va, phys_addr_t pa, int flags)
{
	p4d_t *p4d;
	pud_t *pud;
	pmd_t *pd;
	pte_t *pg;
	int err = -ENOMEM;

	/* Use upper 10 bits of VA to index the first level map */
	p4d = p4d_offset(pgd_offset_k(va), va);
	pud = pud_offset(p4d, va);
	pd = pmd_offset(pud, va);
	/* Use middle 10 bits of VA to index the second-level map */
	pg = pte_alloc_kernel(pd, va); /* from powerpc - pgtable.c */
	/* pg = pte_alloc_kernel(&init_mm, pd, va); */

	if (pg != NULL) {
		err = 0;
		set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT,
				__pgprot(flags)));
		if (unlikely(mem_init_done))
			_tlbie(va);
	}
	return err;
}

/*
 * Map in all of physical memory starting at CONFIG_KERNEL_START.
 */
void __init mapin_ram(void)
{
	unsigned long v, p, s, f;

	v = CONFIG_KERNEL_START;
	p = memory_start;
	for (s = 0; s < lowmem_size; s += PAGE_SIZE) {
		f = _PAGE_PRESENT | _PAGE_ACCESSED |
				_PAGE_SHARED | _PAGE_HWEXEC;
		if ((char *) v < _stext || (char *) v >= _etext)
			f |= _PAGE_WRENABLE;
		else
			/* On the MicroBlaze, no user access
			   forces R/W kernel access */
			f |= _PAGE_USER;
		map_page(v, p, f);
		v += PAGE_SIZE;
		p += PAGE_SIZE;
	}
}

/* is x a power of 2? */
#define is_power_of_2(x)	((x) != 0 && (((x) & ((x) - 1)) == 0))

/* Scan the real Linux page tables and return a PTE pointer for
 * a virtual address in a context.
 * Returns true (1) if PTE was found, zero otherwise.  The pointer to
 * the PTE pointer is unmodified if PTE is not found.
 */
static int get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep)
{
	pgd_t	*pgd;
	p4d_t	*p4d;
	pud_t	*pud;
	pmd_t	*pmd;
	pte_t	*pte;
	int     retval = 0;

	pgd = pgd_offset(mm, addr & PAGE_MASK);
	if (pgd) {
		p4d = p4d_offset(pgd, addr & PAGE_MASK);
		pud = pud_offset(p4d, addr & PAGE_MASK);
		pmd = pmd_offset(pud, addr & PAGE_MASK);
		if (pmd_present(*pmd)) {
			pte = pte_offset_kernel(pmd, addr & PAGE_MASK);
			if (pte) {
				retval = 1;
				*ptep = pte;
			}
		}
	}
	return retval;
}

/* Find physical address for this virtual address.  Normally used by
 * I/O functions, but anyone can call it.
 */
unsigned long iopa(unsigned long addr)
{
	unsigned long pa;

	pte_t *pte;
	struct mm_struct *mm;

	/* Allow mapping of user addresses (within the thread)
	 * for DMA if necessary.
	 */
	if (addr < TASK_SIZE)
		mm = current->mm;
	else
		mm = &init_mm;

	pa = 0;
	if (get_pteptr(mm, addr, &pte))
		pa = (pte_val(*pte) & PAGE_MASK) | (addr & ~PAGE_MASK);

	return pa;
}

__ref pte_t *pte_alloc_one_kernel(struct mm_struct *mm)
{
	pte_t *pte;
	if (mem_init_done) {
		pte = (pte_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
	} else {
		pte = (pte_t *)early_get_page();
		if (pte)
			clear_page(pte);
	}
	return pte;
}

void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t flags)
{
	unsigned long address = __fix_to_virt(idx);

	if (idx >= __end_of_fixed_addresses)
		BUG();

	map_page(address, phys, pgprot_val(flags));
}