ARC: support HIGHMEM even without PAE40
[deliverable/linux.git] / arch / arc / mm / init.c
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1/*
2 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 */
8
9#include <linux/kernel.h>
10#include <linux/mm.h>
11#include <linux/bootmem.h>
12#include <linux/memblock.h>
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13#ifdef CONFIG_BLK_DEV_INITRD
14#include <linux/initrd.h>
15#endif
1b10cb21 16#include <linux/of_fdt.h>
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17#include <linux/swap.h>
18#include <linux/module.h>
29e33226 19#include <linux/highmem.h>
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20#include <asm/page.h>
21#include <asm/pgalloc.h>
22#include <asm/sections.h>
23#include <asm/arcregs.h>
24
25pgd_t swapper_pg_dir[PTRS_PER_PGD] __aligned(PAGE_SIZE);
26char empty_zero_page[PAGE_SIZE] __aligned(PAGE_SIZE);
27EXPORT_SYMBOL(empty_zero_page);
28
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29static const unsigned long low_mem_start = CONFIG_LINUX_LINK_BASE;
30static unsigned long low_mem_sz;
c121c506 31
29e33226 32#ifdef CONFIG_HIGHMEM
26f9d5fd 33static unsigned long min_high_pfn, max_high_pfn;
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34static u64 high_mem_start;
35static u64 high_mem_sz;
36#endif
37
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38#ifdef CONFIG_DISCONTIGMEM
39struct pglist_data node_data[MAX_NUMNODES] __read_mostly;
40EXPORT_SYMBOL(node_data);
41#endif
42
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43/* User can over-ride above with "mem=nnn[KkMm]" in cmdline */
44static int __init setup_mem_sz(char *str)
45{
6101be5a 46 low_mem_sz = memparse(str, NULL) & PAGE_MASK;
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47
48 /* early console might not be setup yet - it will show up later */
6101be5a 49 pr_info("\"mem=%s\": mem sz set to %ldM\n", str, TO_MB(low_mem_sz));
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50
51 return 0;
52}
53early_param("mem", setup_mem_sz);
54
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55void __init early_init_dt_add_memory_arch(u64 base, u64 size)
56{
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57 int in_use = 0;
58
59 if (!low_mem_sz) {
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60 if (base != low_mem_start)
61 panic("CONFIG_LINUX_LINK_BASE != DT memory { }");
62
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63 low_mem_sz = size;
64 in_use = 1;
65 } else {
66#ifdef CONFIG_HIGHMEM
67 high_mem_start = base;
68 high_mem_sz = size;
69 in_use = 1;
70#endif
71 }
f759ee57 72
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73 pr_info("Memory @ %llx [%lldM] %s\n",
74 base, TO_MB(size), !in_use ? "Not used":"");
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75}
76
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77#ifdef CONFIG_BLK_DEV_INITRD
78static int __init early_initrd(char *p)
79{
80 unsigned long start, size;
81 char *endp;
82
83 start = memparse(p, &endp);
84 if (*endp == ',') {
85 size = memparse(endp + 1, NULL);
86
87 initrd_start = (unsigned long)__va(start);
88 initrd_end = (unsigned long)__va(start + size);
89 }
90 return 0;
91}
92early_param("initrd", early_initrd);
93#endif
94
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95/*
96 * First memory setup routine called from setup_arch()
97 * 1. setup swapper's mm @init_mm
98 * 2. Count the pages we have and setup bootmem allocator
99 * 3. zone setup
100 */
101void __init setup_arch_memory(void)
102{
f2e2013f 103 unsigned long zones_size[MAX_NR_ZONES];
29e33226 104 unsigned long zones_holes[MAX_NR_ZONES];
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105
106 init_mm.start_code = (unsigned long)_text;
107 init_mm.end_code = (unsigned long)_etext;
108 init_mm.end_data = (unsigned long)_edata;
109 init_mm.brk = (unsigned long)_end;
110
c121c506 111 /* first page of system - kernel .vector starts here */
f2e2013f 112 min_low_pfn = ARCH_PFN_OFFSET;
c121c506 113
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114 /* Last usable page of low mem */
115 max_low_pfn = max_pfn = PFN_DOWN(low_mem_start + low_mem_sz);
c121c506 116
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117#ifdef CONFIG_FLATMEM
118 /* pfn_valid() uses this */
119 max_mapnr = max_low_pfn - min_low_pfn;
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120#endif
121
6101be5a 122 /*------------- bootmem allocator setup -----------------------*/
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123
124 /*
125 * seed the bootmem allocator after any DT memory node parsing or
126 * "mem=xxx" cmdline overrides have potentially updated @arc_mem_sz
127 *
128 * Only low mem is added, otherwise we have crashes when allocating
129 * mem_map[] itself. NO_BOOTMEM allocates mem_map[] at the end of
130 * avail memory, ending in highmem with a > 32-bit address. However
131 * it then tries to memset it with a truncaed 32-bit handle, causing
132 * the crash
133 */
134
26f9d5fd 135 memblock_add_node(low_mem_start, low_mem_sz, 0);
6101be5a 136 memblock_reserve(low_mem_start, __pa(_end) - low_mem_start);
c121c506 137
d6579e99 138#ifdef CONFIG_BLK_DEV_INITRD
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139 if (initrd_start)
140 memblock_reserve(__pa(initrd_start), initrd_end - initrd_start);
141#endif
142
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143 early_init_fdt_reserve_self();
144 early_init_fdt_scan_reserved_mem();
145
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146 memblock_dump_all();
147
6101be5a 148 /*----------------- node/zones setup --------------------------*/
c121c506 149 memset(zones_size, 0, sizeof(zones_size));
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150 memset(zones_holes, 0, sizeof(zones_holes));
151
6101be5a 152 zones_size[ZONE_NORMAL] = max_low_pfn - min_low_pfn;
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153 zones_holes[ZONE_NORMAL] = 0;
154
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155 /*
156 * We can't use the helper free_area_init(zones[]) because it uses
157 * PAGE_OFFSET to compute the @min_low_pfn which would be wrong
158 * when our kernel doesn't start at PAGE_OFFSET, i.e.
159 * PAGE_OFFSET != CONFIG_LINUX_LINK_BASE
160 */
161 free_area_init_node(0, /* node-id */
162 zones_size, /* num pages per zone */
163 min_low_pfn, /* first pfn of node */
29e33226 164 zones_holes); /* holes */
f2e2013f 165
29e33226 166#ifdef CONFIG_HIGHMEM
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167 /*
168 * Populate a new node with highmem
169 *
170 * On ARC (w/o PAE) HIGHMEM addresses are actually smaller (0 based)
171 * than addresses in normal ala low memory (0x8000_0000 based).
172 * Even with PAE, the huge peripheral space hole would waste a lot of
173 * mem with single mem_map[]. This warrants a mem_map per region design.
174 * Thus HIGHMEM on ARC is imlemented with DISCONTIGMEM.
175 *
176 * DISCONTIGMEM in turns requires multiple nodes. node 0 above is
177 * populated with normal memory zone while node 1 only has highmem
178 */
179 node_set_online(1);
180
181 min_high_pfn = PFN_DOWN(high_mem_start);
182 max_high_pfn = PFN_DOWN(high_mem_start + high_mem_sz);
183
184 zones_size[ZONE_NORMAL] = 0;
185 zones_holes[ZONE_NORMAL] = 0;
186
187 zones_size[ZONE_HIGHMEM] = max_high_pfn - min_high_pfn;
188 zones_holes[ZONE_HIGHMEM] = 0;
189
190 free_area_init_node(1, /* node-id */
191 zones_size, /* num pages per zone */
192 min_high_pfn, /* first pfn of node */
193 zones_holes); /* holes */
194
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195 high_memory = (void *)(min_high_pfn << PAGE_SHIFT);
196 kmap_init();
197#endif
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198}
199
200/*
201 * mem_init - initializes memory
202 *
203 * Frees up bootmem
204 * Calculates and displays memory available/used
205 */
206void __init mem_init(void)
207{
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208#ifdef CONFIG_HIGHMEM
209 unsigned long tmp;
210
211 reset_all_zones_managed_pages();
26f9d5fd 212 for (tmp = min_high_pfn; tmp < max_high_pfn; tmp++)
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213 free_highmem_page(pfn_to_page(tmp));
214#endif
215
0c988534 216 free_all_bootmem();
de35e1b8 217 mem_init_print_info(NULL);
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218}
219
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220/*
221 * free_initmem: Free all the __init memory.
222 */
223void __init_refok free_initmem(void)
224{
dbe67df4 225 free_initmem_default(-1);
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226}
227
228#ifdef CONFIG_BLK_DEV_INITRD
229void __init free_initrd_mem(unsigned long start, unsigned long end)
230{
dbe67df4 231 free_reserved_area((void *)start, (void *)end, -1, "initrd");
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232}
233#endif
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