xref: /openbmc/linux/arch/s390/mm/init.c (revision bb0eb050)
1 /*
2  *  S390 version
3  *    Copyright IBM Corp. 1999
4  *    Author(s): Hartmut Penner (hp@de.ibm.com)
5  *
6  *  Derived from "arch/i386/mm/init.c"
7  *    Copyright (C) 1995  Linus Torvalds
8  */
9 
10 #include <linux/signal.h>
11 #include <linux/sched.h>
12 #include <linux/kernel.h>
13 #include <linux/errno.h>
14 #include <linux/string.h>
15 #include <linux/types.h>
16 #include <linux/ptrace.h>
17 #include <linux/mman.h>
18 #include <linux/mm.h>
19 #include <linux/swap.h>
20 #include <linux/smp.h>
21 #include <linux/init.h>
22 #include <linux/pagemap.h>
23 #include <linux/bootmem.h>
24 #include <linux/memory.h>
25 #include <linux/pfn.h>
26 #include <linux/poison.h>
27 #include <linux/initrd.h>
28 #include <linux/export.h>
29 #include <linux/gfp.h>
30 #include <linux/memblock.h>
31 #include <asm/processor.h>
32 #include <linux/uaccess.h>
33 #include <asm/pgtable.h>
34 #include <asm/pgalloc.h>
35 #include <asm/dma.h>
36 #include <asm/lowcore.h>
37 #include <asm/tlb.h>
38 #include <asm/tlbflush.h>
39 #include <asm/sections.h>
40 #include <asm/ctl_reg.h>
41 #include <asm/sclp.h>
42 #include <asm/set_memory.h>
43 
44 pgd_t swapper_pg_dir[PTRS_PER_PGD] __section(.bss..swapper_pg_dir);
45 
46 unsigned long empty_zero_page, zero_page_mask;
47 EXPORT_SYMBOL(empty_zero_page);
48 EXPORT_SYMBOL(zero_page_mask);
49 
50 static void __init setup_zero_pages(void)
51 {
52 	unsigned int order;
53 	struct page *page;
54 	int i;
55 
56 	/* Latest machines require a mapping granularity of 512KB */
57 	order = 7;
58 
59 	/* Limit number of empty zero pages for small memory sizes */
60 	while (order > 2 && (totalram_pages >> 10) < (1UL << order))
61 		order--;
62 
63 	empty_zero_page = __get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
64 	if (!empty_zero_page)
65 		panic("Out of memory in setup_zero_pages");
66 
67 	page = virt_to_page((void *) empty_zero_page);
68 	split_page(page, order);
69 	for (i = 1 << order; i > 0; i--) {
70 		mark_page_reserved(page);
71 		page++;
72 	}
73 
74 	zero_page_mask = ((PAGE_SIZE << order) - 1) & PAGE_MASK;
75 }
76 
77 /*
78  * paging_init() sets up the page tables
79  */
80 void __init paging_init(void)
81 {
82 	unsigned long max_zone_pfns[MAX_NR_ZONES];
83 	unsigned long pgd_type, asce_bits;
84 
85 	init_mm.pgd = swapper_pg_dir;
86 	if (VMALLOC_END > (1UL << 42)) {
87 		asce_bits = _ASCE_TYPE_REGION2 | _ASCE_TABLE_LENGTH;
88 		pgd_type = _REGION2_ENTRY_EMPTY;
89 	} else {
90 		asce_bits = _ASCE_TYPE_REGION3 | _ASCE_TABLE_LENGTH;
91 		pgd_type = _REGION3_ENTRY_EMPTY;
92 	}
93 	init_mm.context.asce = (__pa(init_mm.pgd) & PAGE_MASK) | asce_bits;
94 	S390_lowcore.kernel_asce = init_mm.context.asce;
95 	clear_table((unsigned long *) init_mm.pgd, pgd_type,
96 		    sizeof(unsigned long)*2048);
97 	vmem_map_init();
98 
99         /* enable virtual mapping in kernel mode */
100 	__ctl_load(S390_lowcore.kernel_asce, 1, 1);
101 	__ctl_load(S390_lowcore.kernel_asce, 7, 7);
102 	__ctl_load(S390_lowcore.kernel_asce, 13, 13);
103 	__arch_local_irq_stosm(0x04);
104 
105 	sparse_memory_present_with_active_regions(MAX_NUMNODES);
106 	sparse_init();
107 	memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
108 	max_zone_pfns[ZONE_DMA] = PFN_DOWN(MAX_DMA_ADDRESS);
109 	max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
110 	free_area_init_nodes(max_zone_pfns);
111 }
112 
113 void mark_rodata_ro(void)
114 {
115 	unsigned long size = __end_ro_after_init - __start_ro_after_init;
116 
117 	set_memory_ro((unsigned long)__start_ro_after_init, size >> PAGE_SHIFT);
118 	pr_info("Write protected read-only-after-init data: %luk\n", size >> 10);
119 }
120 
121 void __init mem_init(void)
122 {
123 	cpumask_set_cpu(0, &init_mm.context.cpu_attach_mask);
124 	cpumask_set_cpu(0, mm_cpumask(&init_mm));
125 
126 	set_max_mapnr(max_low_pfn);
127         high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);
128 
129 	/* Setup guest page hinting */
130 	cmma_init();
131 
132 	/* this will put all low memory onto the freelists */
133 	free_all_bootmem();
134 	setup_zero_pages();	/* Setup zeroed pages. */
135 
136 	mem_init_print_info(NULL);
137 }
138 
139 void free_initmem(void)
140 {
141 	__set_memory((unsigned long) _sinittext,
142 		     (_einittext - _sinittext) >> PAGE_SHIFT,
143 		     SET_MEMORY_RW | SET_MEMORY_NX);
144 	free_initmem_default(POISON_FREE_INITMEM);
145 }
146 
147 #ifdef CONFIG_BLK_DEV_INITRD
148 void __init free_initrd_mem(unsigned long start, unsigned long end)
149 {
150 	free_reserved_area((void *)start, (void *)end, POISON_FREE_INITMEM,
151 			   "initrd");
152 }
153 #endif
154 
155 unsigned long memory_block_size_bytes(void)
156 {
157 	/*
158 	 * Make sure the memory block size is always greater
159 	 * or equal than the memory increment size.
160 	 */
161 	return max_t(unsigned long, MIN_MEMORY_BLOCK_SIZE, sclp.rzm);
162 }
163 
164 #ifdef CONFIG_MEMORY_HOTPLUG
165 int arch_add_memory(int nid, u64 start, u64 size, bool for_device)
166 {
167 	unsigned long zone_start_pfn, zone_end_pfn, nr_pages;
168 	unsigned long start_pfn = PFN_DOWN(start);
169 	unsigned long size_pages = PFN_DOWN(size);
170 	pg_data_t *pgdat = NODE_DATA(nid);
171 	struct zone *zone;
172 	int rc, i;
173 
174 	rc = vmem_add_mapping(start, size);
175 	if (rc)
176 		return rc;
177 
178 	for (i = 0; i < MAX_NR_ZONES; i++) {
179 		zone = pgdat->node_zones + i;
180 		if (zone_idx(zone) != ZONE_MOVABLE) {
181 			/* Add range within existing zone limits, if possible */
182 			zone_start_pfn = zone->zone_start_pfn;
183 			zone_end_pfn = zone->zone_start_pfn +
184 				       zone->spanned_pages;
185 		} else {
186 			/* Add remaining range to ZONE_MOVABLE */
187 			zone_start_pfn = start_pfn;
188 			zone_end_pfn = start_pfn + size_pages;
189 		}
190 		if (start_pfn < zone_start_pfn || start_pfn >= zone_end_pfn)
191 			continue;
192 		nr_pages = (start_pfn + size_pages > zone_end_pfn) ?
193 			   zone_end_pfn - start_pfn : size_pages;
194 		rc = __add_pages(nid, zone, start_pfn, nr_pages);
195 		if (rc)
196 			break;
197 		start_pfn += nr_pages;
198 		size_pages -= nr_pages;
199 		if (!size_pages)
200 			break;
201 	}
202 	if (rc)
203 		vmem_remove_mapping(start, size);
204 	return rc;
205 }
206 
207 #ifdef CONFIG_MEMORY_HOTREMOVE
208 int arch_remove_memory(u64 start, u64 size)
209 {
210 	/*
211 	 * There is no hardware or firmware interface which could trigger a
212 	 * hot memory remove on s390. So there is nothing that needs to be
213 	 * implemented.
214 	 */
215 	return -EBUSY;
216 }
217 #endif
218 #endif /* CONFIG_MEMORY_HOTPLUG */
219