xref: /openbmc/linux/arch/um/kernel/mem.c (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
1 /*
2  * Copyright (C) 2000 - 2003 Jeff Dike (jdike@addtoit.com)
3  * Licensed under the GPL
4  */
5 
6 #include "linux/stddef.h"
7 #include "linux/kernel.h"
8 #include "linux/mm.h"
9 #include "linux/bootmem.h"
10 #include "linux/swap.h"
11 #include "linux/highmem.h"
12 #include "linux/gfp.h"
13 #include "asm/page.h"
14 #include "asm/fixmap.h"
15 #include "asm/pgalloc.h"
16 #include "user_util.h"
17 #include "kern_util.h"
18 #include "kern.h"
19 #include "mem_user.h"
20 #include "uml_uaccess.h"
21 #include "os.h"
22 #include "linux/types.h"
23 #include "linux/string.h"
24 #include "init.h"
25 #include "kern_constants.h"
26 
27 extern char __binary_start;
28 
29 /* Changed during early boot */
30 unsigned long *empty_zero_page = NULL;
31 unsigned long *empty_bad_page = NULL;
32 pgd_t swapper_pg_dir[PTRS_PER_PGD];
33 unsigned long highmem;
34 int kmalloc_ok = 0;
35 
36 static unsigned long brk_end;
37 
38 void unmap_physmem(void)
39 {
40 	os_unmap_memory((void *) brk_end, uml_reserved - brk_end);
41 }
42 
43 static void map_cb(void *unused)
44 {
45 	map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0);
46 }
47 
48 #ifdef CONFIG_HIGHMEM
49 static void setup_highmem(unsigned long highmem_start,
50 			  unsigned long highmem_len)
51 {
52 	struct page *page;
53 	unsigned long highmem_pfn;
54 	int i;
55 
56 	highmem_pfn = __pa(highmem_start) >> PAGE_SHIFT;
57 	for(i = 0; i < highmem_len >> PAGE_SHIFT; i++){
58 		page = &mem_map[highmem_pfn + i];
59 		ClearPageReserved(page);
60 		set_page_count(page, 1);
61 		__free_page(page);
62 	}
63 }
64 #endif
65 
66 void mem_init(void)
67 {
68 	unsigned long start;
69 
70 	max_low_pfn = (high_physmem - uml_physmem) >> PAGE_SHIFT;
71 
72         /* clear the zero-page */
73         memset((void *) empty_zero_page, 0, PAGE_SIZE);
74 
75 	/* Map in the area just after the brk now that kmalloc is about
76 	 * to be turned on.
77 	 */
78 	brk_end = (unsigned long) UML_ROUND_UP(sbrk(0));
79 	map_cb(NULL);
80 	initial_thread_cb(map_cb, NULL);
81 	free_bootmem(__pa(brk_end), uml_reserved - brk_end);
82 	uml_reserved = brk_end;
83 
84 	/* Fill in any hole at the start of the binary */
85 	start = (unsigned long) &__binary_start & PAGE_MASK;
86 	if(uml_physmem != start){
87 		map_memory(uml_physmem, __pa(uml_physmem), start - uml_physmem,
88 			   1, 1, 0);
89 	}
90 
91 	/* this will put all low memory onto the freelists */
92 	totalram_pages = free_all_bootmem();
93 	totalhigh_pages = highmem >> PAGE_SHIFT;
94 	totalram_pages += totalhigh_pages;
95 	num_physpages = totalram_pages;
96 	max_pfn = totalram_pages;
97 	printk(KERN_INFO "Memory: %luk available\n",
98 	       (unsigned long) nr_free_pages() << (PAGE_SHIFT-10));
99 	kmalloc_ok = 1;
100 
101 #ifdef CONFIG_HIGHMEM
102 	setup_highmem(end_iomem, highmem);
103 #endif
104 }
105 
106 /*
107  * Create a page table and place a pointer to it in a middle page
108  * directory entry.
109  */
110 static void __init one_page_table_init(pmd_t *pmd)
111 {
112 	if (pmd_none(*pmd)) {
113 		pte_t *pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
114 		set_pmd(pmd, __pmd(_KERNPG_TABLE +
115 					   (unsigned long) __pa(pte)));
116 		if (pte != pte_offset_kernel(pmd, 0))
117 			BUG();
118 	}
119 }
120 
121 static void __init one_md_table_init(pud_t *pud)
122 {
123 #ifdef CONFIG_3_LEVEL_PGTABLES
124 	pmd_t *pmd_table = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE);
125 	set_pud(pud, __pud(_KERNPG_TABLE + (unsigned long) __pa(pmd_table)));
126 	if (pmd_table != pmd_offset(pud, 0))
127 		BUG();
128 #endif
129 }
130 
131 static void __init fixrange_init(unsigned long start, unsigned long end,
132 				 pgd_t *pgd_base)
133 {
134 	pgd_t *pgd;
135 	pud_t *pud;
136 	pmd_t *pmd;
137 	int i, j;
138 	unsigned long vaddr;
139 
140 	vaddr = start;
141 	i = pgd_index(vaddr);
142 	j = pmd_index(vaddr);
143 	pgd = pgd_base + i;
144 
145 	for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) {
146 		pud = pud_offset(pgd, vaddr);
147 		if (pud_none(*pud))
148 			one_md_table_init(pud);
149 		pmd = pmd_offset(pud, vaddr);
150 		for (; (j < PTRS_PER_PMD) && (vaddr != end); pmd++, j++) {
151 			one_page_table_init(pmd);
152 			vaddr += PMD_SIZE;
153 		}
154 		j = 0;
155 	}
156 }
157 
158 #ifdef CONFIG_HIGHMEM
159 pte_t *kmap_pte;
160 pgprot_t kmap_prot;
161 
162 #define kmap_get_fixmap_pte(vaddr)					\
163 	pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)),\
164  			  (vaddr)), (vaddr))
165 
166 static void __init kmap_init(void)
167 {
168 	unsigned long kmap_vstart;
169 
170 	/* cache the first kmap pte */
171 	kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
172 	kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
173 
174 	kmap_prot = PAGE_KERNEL;
175 }
176 
177 static void init_highmem(void)
178 {
179 	pgd_t *pgd;
180 	pud_t *pud;
181 	pmd_t *pmd;
182 	pte_t *pte;
183 	unsigned long vaddr;
184 
185 	/*
186 	 * Permanent kmaps:
187 	 */
188 	vaddr = PKMAP_BASE;
189 	fixrange_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, swapper_pg_dir);
190 
191 	pgd = swapper_pg_dir + pgd_index(vaddr);
192 	pud = pud_offset(pgd, vaddr);
193 	pmd = pmd_offset(pud, vaddr);
194 	pte = pte_offset_kernel(pmd, vaddr);
195 	pkmap_page_table = pte;
196 
197 	kmap_init();
198 }
199 #endif /* CONFIG_HIGHMEM */
200 
201 static void __init fixaddr_user_init( void)
202 {
203 #ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
204 	long size = FIXADDR_USER_END - FIXADDR_USER_START;
205 	pgd_t *pgd;
206 	pud_t *pud;
207 	pmd_t *pmd;
208 	pte_t *pte;
209 	unsigned long paddr, vaddr = FIXADDR_USER_START;
210 
211 	if (  ! size )
212 		return;
213 
214 	fixrange_init( FIXADDR_USER_START, FIXADDR_USER_END, swapper_pg_dir);
215 	paddr = (unsigned long)alloc_bootmem_low_pages( size);
216 	memcpy( (void *)paddr, (void *)FIXADDR_USER_START, size);
217 	paddr = __pa(paddr);
218 	for ( ; size > 0; size-=PAGE_SIZE, vaddr+=PAGE_SIZE, paddr+=PAGE_SIZE){
219 		pgd = swapper_pg_dir + pgd_index(vaddr);
220 		pud = pud_offset(pgd, vaddr);
221 		pmd = pmd_offset(pud, vaddr);
222 		pte = pte_offset_kernel(pmd, vaddr);
223 		pte_set_val( (*pte), paddr, PAGE_READONLY);
224 	}
225 #endif
226 }
227 
228 void paging_init(void)
229 {
230 	unsigned long zones_size[MAX_NR_ZONES], vaddr;
231 	int i;
232 
233 	empty_zero_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
234 	empty_bad_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
235 	for(i=0;i<sizeof(zones_size)/sizeof(zones_size[0]);i++)
236 		zones_size[i] = 0;
237 	zones_size[0] = (end_iomem >> PAGE_SHIFT) - (uml_physmem >> PAGE_SHIFT);
238 	zones_size[2] = highmem >> PAGE_SHIFT;
239 	free_area_init(zones_size);
240 
241 	/*
242 	 * Fixed mappings, only the page table structure has to be
243 	 * created - mappings will be set by set_fixmap():
244 	 */
245 	vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
246 	fixrange_init(vaddr, FIXADDR_TOP, swapper_pg_dir);
247 
248 	fixaddr_user_init();
249 
250 #ifdef CONFIG_HIGHMEM
251 	init_highmem();
252 #endif
253 }
254 
255 struct page *arch_validate(struct page *page, gfp_t mask, int order)
256 {
257 	unsigned long addr, zero = 0;
258 	int i;
259 
260  again:
261 	if(page == NULL) return(page);
262 	if(PageHighMem(page)) return(page);
263 
264 	addr = (unsigned long) page_address(page);
265 	for(i = 0; i < (1 << order); i++){
266 		current->thread.fault_addr = (void *) addr;
267 		if(__do_copy_to_user((void __user *) addr, &zero,
268 				     sizeof(zero),
269 				     &current->thread.fault_addr,
270 				     &current->thread.fault_catcher)){
271 			if(!(mask & __GFP_WAIT)) return(NULL);
272 			else break;
273 		}
274 		addr += PAGE_SIZE;
275 	}
276 
277 	if(i == (1 << order)) return(page);
278 	page = alloc_pages(mask, order);
279 	goto again;
280 }
281 
282 /* This can't do anything because nothing in the kernel image can be freed
283  * since it's not in kernel physical memory.
284  */
285 
286 void free_initmem(void)
287 {
288 }
289 
290 #ifdef CONFIG_BLK_DEV_INITRD
291 
292 void free_initrd_mem(unsigned long start, unsigned long end)
293 {
294 	if (start < end)
295 		printk ("Freeing initrd memory: %ldk freed\n",
296 			(end - start) >> 10);
297 	for (; start < end; start += PAGE_SIZE) {
298 		ClearPageReserved(virt_to_page(start));
299 		set_page_count(virt_to_page(start), 1);
300 		free_page(start);
301 		totalram_pages++;
302 	}
303 }
304 
305 #endif
306 
307 void show_mem(void)
308 {
309         int pfn, total = 0, reserved = 0;
310         int shared = 0, cached = 0;
311         int highmem = 0;
312 	struct page *page;
313 
314         printk("Mem-info:\n");
315         show_free_areas();
316         printk("Free swap:       %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));
317         pfn = max_mapnr;
318         while(pfn-- > 0) {
319 		page = pfn_to_page(pfn);
320                 total++;
321                 if(PageHighMem(page))
322                         highmem++;
323                 if(PageReserved(page))
324                         reserved++;
325                 else if(PageSwapCache(page))
326                         cached++;
327                 else if(page_count(page))
328                         shared += page_count(page) - 1;
329         }
330         printk("%d pages of RAM\n", total);
331         printk("%d pages of HIGHMEM\n", highmem);
332         printk("%d reserved pages\n", reserved);
333         printk("%d pages shared\n", shared);
334         printk("%d pages swap cached\n", cached);
335 }
336 
337 /*
338  * Allocate and free page tables.
339  */
340 
341 pgd_t *pgd_alloc(struct mm_struct *mm)
342 {
343 	pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL);
344 
345 	if (pgd) {
346 		memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
347 		memcpy(pgd + USER_PTRS_PER_PGD,
348 		       swapper_pg_dir + USER_PTRS_PER_PGD,
349 		       (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
350 	}
351 	return pgd;
352 }
353 
354 void pgd_free(pgd_t *pgd)
355 {
356 	free_page((unsigned long) pgd);
357 }
358 
359 pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
360 {
361 	pte_t *pte;
362 
363 	pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
364 	return pte;
365 }
366 
367 struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
368 {
369 	struct page *pte;
370 
371 	pte = alloc_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
372 	return pte;
373 }
374 
375 struct iomem_region *iomem_regions = NULL;
376 int iomem_size = 0;
377 
378 extern int parse_iomem(char *str, int *add) __init;
379 
380 __uml_setup("iomem=", parse_iomem,
381 "iomem=<name>,<file>\n"
382 "    Configure <file> as an IO memory region named <name>.\n\n"
383 );
384 
385 /*
386  * Overrides for Emacs so that we follow Linus's tabbing style.
387  * Emacs will notice this stuff at the end of the file and automatically
388  * adjust the settings for this buffer only.  This must remain at the end
389  * of the file.
390  * ---------------------------------------------------------------------------
391  * Local variables:
392  * c-file-style: "linux"
393  * End:
394  */
395