1/*
2 *  arch/s390/mm/init.c
3 *
4 *  S390 version
5 *    Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
6 *    Author(s): Hartmut Penner (hpenner@de.ibm.com)
7 *
8 *  Derived from "arch/i386/mm/init.c"
9 *    Copyright (C) 1995  Linus Torvalds
10 */
11
12#include <linux/config.h>
13#include <linux/signal.h>
14#include <linux/sched.h>
15#include <linux/kernel.h>
16#include <linux/errno.h>
17#include <linux/string.h>
18#include <linux/types.h>
19#include <linux/ptrace.h>
20#include <linux/mman.h>
21#include <linux/mm.h>
22#include <linux/swap.h>
23#include <linux/smp.h>
24#include <linux/init.h>
25#ifdef CONFIG_BLK_DEV_INITRD
26#include <linux/blk.h>
27#endif
28#include <linux/pagemap.h>
29#include <linux/bootmem.h>
30
31#include <asm/processor.h>
32#include <asm/system.h>
33#include <asm/uaccess.h>
34#include <asm/pgtable.h>
35#include <asm/pgalloc.h>
36#include <asm/dma.h>
37#include <asm/lowcore.h>
38#include <asm/tlb.h>
39
40mmu_gather_t mmu_gathers[NR_CPUS];
41
42static unsigned long totalram_pages;
43
44pgd_t swapper_pg_dir[PTRS_PER_PGD] __attribute__((__aligned__(PAGE_SIZE)));
45char  empty_zero_page[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
46
47pmd_t *pgd_populate(struct mm_struct *mm, pgd_t *pgd, pmd_t *pmd)
48{
49        unsigned long addr = (unsigned long) pgd;
50        unsigned long *pgd_slot =  (unsigned long *) (addr & -8);
51        unsigned long offset = addr & 4;
52	pmd_t *new, *pmd2;
53	int i;
54
55        if (offset == 0 &&
56	    ((*pgd_slot & _PGD_ENTRY_INV) != 0 ||
57	     (*pgd_slot & _PGD_ENTRY_LEN(2)) == 0)) {
58                /* Set lower pmd, upper pmd is empty. */
59                *pgd_slot = __pa(pmd) | _PGD_ENTRY_MASK |
60                                _PGD_ENTRY_OFF(0) | _PGD_ENTRY_LEN(1);
61                return pmd;
62        }
63        if (offset == 4 &&
64	    ((*pgd_slot & _PGD_ENTRY_INV) != 0 ||
65	     (*pgd_slot & _PGD_ENTRY_OFF(2)) != 0)) {
66                /* Lower pmd empty, set upper pmd. */
67                *pgd_slot = (__pa(pmd) - 0x2000) | _PGD_ENTRY_MASK |
68                                _PGD_ENTRY_OFF(2) | _PGD_ENTRY_LEN(3);
69                return pmd;
70        }
71        /* We have to enlarge the pmd to 16K if we arrive here. */
72	new = (pmd_t *) __get_free_pages(GFP_KERNEL, 2);
73	if (new == NULL) {
74		pmd_free(pmd);
75		return NULL;
76	}
77	/* Set the PG_arch_1 bit on the first and the third pmd page
78           so that pmd_free_fast can recognize pmds that have been
79           allocated with an order 2 allocation.  */
80	set_bit(PG_arch_1, &virt_to_page(new)->flags);
81	set_bit(PG_arch_1, &virt_to_page(new+PTRS_PER_PMD)->flags);
82	/* Now copy the two pmds to the new memory area. */
83	if (offset == 0) {
84		pmd2 = (pmd_t *)(*pgd_slot & PAGE_MASK) + PTRS_PER_PMD;
85		memcpy(new, pmd, sizeof(pmd_t)*PTRS_PER_PMD);
86		memcpy(new + PTRS_PER_PMD, pmd2, sizeof(pmd_t)*PTRS_PER_PMD);
87	} else {
88		pmd2 = (pmd_t *)(*pgd_slot & PAGE_MASK);
89		memcpy(new, pmd2, sizeof(pmd_t)*PTRS_PER_PMD);
90		memcpy(new + PTRS_PER_PMD, pmd, sizeof(pmd_t)*PTRS_PER_PMD);
91	}
92	*pgd_slot = __pa(new) | _PGD_ENTRY_MASK |
93			_PGD_ENTRY_OFF(0) | _PGD_ENTRY_LEN(3);
94	for (i = 0; i < PTRS_PER_PMD; i++) {
95		pmd_clear(pmd + i);
96		pmd_clear(pmd2 + i);
97	}
98	pmd_free(pmd);
99	pmd_free(pmd2);
100	return new;
101}
102
103void pmd_free_order2(pmd_t *pmd)
104{
105	pmd_t *pmd2 = (pmd_t *) ((unsigned long) pmd ^ 8192);
106
107	clear_bit(PG_arch_1, &virt_to_page(pmd)->flags);
108	if (test_bit(PG_arch_1, &virt_to_page(pmd2)->flags) == 0) {
109		/* The other pmd of the order 2 allocation has already
110		   been freed. Now we can release the order 2 allocation.  */
111		free_pages((unsigned long) pmd & ~8192, 2);
112	}
113}
114
115int do_check_pgt_cache(int low, int high)
116{
117        int freed = 0;
118        if(pgtable_cache_size > high) {
119                do {
120                        if(pgd_quicklist) {
121				free_pgd_slow(get_pgd_fast());
122				freed += 2;
123			}
124                        if(pmd_quicklist) {
125				pmd_free_slow(pmd_alloc_one_fast(NULL, 0));
126				freed += 2;
127			}
128                        if(pte_quicklist) {
129				pte_free_slow(pte_alloc_one_fast(NULL, 0));
130				freed += 1;
131			}
132                } while(pgtable_cache_size > low);
133        }
134        return freed;
135}
136
137void show_mem(void)
138{
139        int i, total = 0,reserved = 0;
140        int shared = 0, cached = 0;
141
142        printk("Mem-info:\n");
143        show_free_areas();
144        printk("Free swap:       %6dkB\n",nr_swap_pages<<(PAGE_SHIFT-10));
145        i = max_mapnr;
146        while (i-- > 0) {
147                total++;
148                if (PageReserved(mem_map+i))
149                        reserved++;
150                else if (PageSwapCache(mem_map+i))
151                        cached++;
152                else if (page_count(mem_map+i))
153                        shared += atomic_read(&mem_map[i].count) - 1;
154        }
155        printk("%d pages of RAM\n",total);
156        printk("%d reserved pages\n",reserved);
157        printk("%d pages shared\n",shared);
158        printk("%d pages swap cached\n",cached);
159        printk("%ld pages in page table cache\n",pgtable_cache_size);
160        show_buffers();
161}
162
163/* References to section boundaries */
164
165extern unsigned long _text;
166extern unsigned long _etext;
167extern unsigned long _edata;
168extern unsigned long __bss_start;
169extern unsigned long _end;
170
171extern unsigned long __init_begin;
172extern unsigned long __init_end;
173
174/*
175 * paging_init() sets up the page tables
176 */
177
178unsigned long last_valid_pfn;
179
180void __init paging_init(void)
181{
182	unsigned long zones_size[MAX_NR_ZONES] = {0, 0, 0};
183	static const int ssm_mask = 0x04000000L;
184	unsigned long dma_pfn, address, end_mem;
185        pgd_t * pg_dir;
186	int     i,j,k;
187
188	dma_pfn = MAX_DMA_ADDRESS >> PAGE_SHIFT;
189
190	if (dma_pfn > max_low_pfn)
191		zones_size[ZONE_DMA] = max_low_pfn;
192	else {
193		zones_size[ZONE_DMA] = dma_pfn;
194		zones_size[ZONE_NORMAL] = max_low_pfn - dma_pfn;
195	}
196
197	/* Initialize mem_map[].  */
198	free_area_init(zones_size);
199
200	/*
201	 * map whole physical memory to virtual memory (identity mapping)
202	 */
203        pg_dir = swapper_pg_dir;
204	address = 0;
205	end_mem = (unsigned long) __va(max_low_pfn*PAGE_SIZE);
206        for (i = 0 ; i < PTRS_PER_PGD/2 ; i++, pg_dir += 2) {
207		pmd_t *pm_dir;
208
209                if (address >= end_mem) {
210                        pgd_clear(pg_dir);
211                        continue;
212                }
213
214	        pm_dir = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE*4);
215		*((unsigned long *) pg_dir) = __pa(pm_dir) | _PGD_ENTRY_MASK |
216			_PGD_ENTRY_LEN(3) | _PGD_ENTRY_OFF(0);
217
218                for (j = 0 ; j < PTRS_PER_PMD*2 ; j++, pm_dir++) {
219			pte_t *pt_dir;
220
221                        if (address >= end_mem) {
222                                pmd_clear(pm_dir);
223                                continue;
224                        }
225
226                        pt_dir = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
227                        pmd_populate(&init_mm, pm_dir, pt_dir);
228
229                        for (k = 0 ; k < PTRS_PER_PTE ; k++,pt_dir++) {
230                                pte_t pte = mk_pte_phys(address, PAGE_KERNEL);
231                                if (address >= end_mem) {
232                                        pte_clear(&pte);
233                                        continue;
234                                }
235                                set_pte(pt_dir, pte);
236                                address += PAGE_SIZE;
237                        }
238                }
239        }
240
241        /* enable virtual mapping in kernel mode */
242        __asm__ __volatile__("lctlg 1,1,%0\n\t"
243                             "lctlg 7,7,%0\n\t"
244                             "lctlg 13,13,%0\n\t"
245                             "ssm   %1"
246			     : :"m" (__pa(swapper_pg_dir) | _KERN_REGION_TABLE),
247			        "m" (ssm_mask));
248        local_flush_tlb();
249
250        return;
251}
252
253void __init mem_init(void)
254{
255	unsigned long codesize, reservedpages, datasize, initsize;
256
257        max_mapnr = num_physpages = max_low_pfn;
258        high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);
259
260        /* clear the zero-page */
261        memset(empty_zero_page, 0, PAGE_SIZE);
262
263	/* this will put all low memory onto the freelists */
264	totalram_pages += free_all_bootmem();
265
266	reservedpages = 0;
267
268	codesize =  (unsigned long) &_etext - (unsigned long) &_text;
269	datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
270	initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;
271        printk("Memory: %luk/%luk available (%ldk kernel code, %ldk reserved, %ldk data, %ldk init)\n",
272                (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
273                max_mapnr << (PAGE_SHIFT-10),
274                codesize >> 10,
275                reservedpages << (PAGE_SHIFT-10),
276                datasize >>10,
277                initsize >> 10);
278}
279
280void free_initmem(void)
281{
282        unsigned long addr;
283
284        addr = (unsigned long)(&__init_begin);
285        for (; addr < (unsigned long)(&__init_end); addr += PAGE_SIZE) {
286		ClearPageReserved(virt_to_page(addr));
287		set_page_count(virt_to_page(addr), 1);
288		free_page(addr);
289		totalram_pages++;
290        }
291        printk (KERN_INFO "Freeing unused kernel memory: %ldk freed\n",
292		(&__init_end - &__init_begin) >> 10);
293}
294
295#ifdef CONFIG_BLK_DEV_INITRD
296void free_initrd_mem(unsigned long start, unsigned long end)
297{
298        if (start < end)
299                printk (KERN_INFO "Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
300	for (; start < end; start += PAGE_SIZE) {
301                ClearPageReserved(virt_to_page(start));
302                set_page_count(virt_to_page(start), 1);
303		free_page(start);
304		totalram_pages++;
305	}
306}
307#endif
308
309void si_meminfo(struct sysinfo *val)
310{
311        val->totalram = totalram_pages;
312	val->sharedram = 0;
313	val->freeram = nr_free_pages();
314	val->bufferram = atomic_read(&buffermem_pages);
315	val->totalhigh = 0;
316	val->freehigh = 0;
317	val->mem_unit = PAGE_SIZE;
318}
319
320/*
321 * Overrides for Emacs so that we follow Linus's tabbing style.
322 * Emacs will notice this stuff at the end of the file and automatically
323 * adjust the settings for this buffer only.  This must remain at the end
324 * of the file.
325 * ---------------------------------------------------------------------------
326 * Local variables:
327 * c-indent-level: 4
328 * c-brace-imaginary-offset: 0
329 * c-brace-offset: -4
330 * c-argdecl-indent: 4
331 * c-label-offset: -4
332 * c-continued-statement-offset: 4
333 * c-continued-brace-offset: 0
334 * indent-tabs-mode: nil
335 * tab-width: 8
336 * End:
337 */
338