1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
4 */
5
6#include <linux/kernel.h>
7#include <linux/mm.h>
8#include <linux/memblock.h>
9#ifdef CONFIG_BLK_DEV_INITRD
10#include <linux/initrd.h>
11#endif
12#include <linux/of_fdt.h>
13#include <linux/swap.h>
14#include <linux/module.h>
15#include <linux/highmem.h>
16#include <asm/page.h>
17#include <asm/sections.h>
18#include <asm/setup.h>
19#include <asm/arcregs.h>
20
21pgd_t swapper_pg_dir[PTRS_PER_PGD] __aligned(PAGE_SIZE);
22char empty_zero_page[PAGE_SIZE] __aligned(PAGE_SIZE);
23EXPORT_SYMBOL(empty_zero_page);
24
25static const unsigned long low_mem_start = CONFIG_LINUX_RAM_BASE;
26static unsigned long low_mem_sz;
27
28#ifdef CONFIG_HIGHMEM
29static unsigned long min_high_pfn, max_high_pfn;
30static phys_addr_t high_mem_start;
31static phys_addr_t high_mem_sz;
32unsigned long arch_pfn_offset;
33EXPORT_SYMBOL(arch_pfn_offset);
34#endif
35
36long __init arc_get_mem_sz(void)
37{
38 return low_mem_sz;
39}
40
41/* User can over-ride above with "mem=nnn[KkMm]" in cmdline */
42static int __init setup_mem_sz(char *str)
43{
44 low_mem_sz = memparse(ptr: str, NULL) & PAGE_MASK;
45
46 /* early console might not be setup yet - it will show up later */
47 pr_info("\"mem=%s\": mem sz set to %ldM\n", str, TO_MB(low_mem_sz));
48
49 return 0;
50}
51early_param("mem", setup_mem_sz);
52
53void __init early_init_dt_add_memory_arch(u64 base, u64 size)
54{
55 int in_use = 0;
56
57 if (!low_mem_sz) {
58 if (base != low_mem_start)
59 panic(fmt: "CONFIG_LINUX_RAM_BASE != DT memory { }");
60
61 low_mem_sz = size;
62 in_use = 1;
63 memblock_add_node(base, size, nid: 0, flags: MEMBLOCK_NONE);
64 } else {
65#ifdef CONFIG_HIGHMEM
66 high_mem_start = base;
67 high_mem_sz = size;
68 in_use = 1;
69 memblock_add_node(base, size, 1, MEMBLOCK_NONE);
70 memblock_reserve(base, size);
71#endif
72 }
73
74 pr_info("Memory @ %llx [%lldM] %s\n",
75 base, TO_MB(size), !in_use ? "Not used":"");
76}
77
78/*
79 * First memory setup routine called from setup_arch()
80 * 1. setup swapper's mm @init_mm
81 * 2. Count the pages we have and setup bootmem allocator
82 * 3. zone setup
83 */
84void __init setup_arch_memory(void)
85{
86 unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 };
87
88 setup_initial_init_mm(start_code: _text, end_code: _etext, end_data: _edata, brk: _end);
89
90 /* first page of system - kernel .vector starts here */
91 min_low_pfn = virt_to_pfn((void *)CONFIG_LINUX_RAM_BASE);
92
93 /* Last usable page of low mem */
94 max_low_pfn = max_pfn = PFN_DOWN(low_mem_start + low_mem_sz);
95
96 /*------------- bootmem allocator setup -----------------------*/
97
98 /*
99 * seed the bootmem allocator after any DT memory node parsing or
100 * "mem=xxx" cmdline overrides have potentially updated @arc_mem_sz
101 *
102 * Only low mem is added, otherwise we have crashes when allocating
103 * mem_map[] itself. NO_BOOTMEM allocates mem_map[] at the end of
104 * avail memory, ending in highmem with a > 32-bit address. However
105 * it then tries to memset it with a truncaed 32-bit handle, causing
106 * the crash
107 */
108
109 memblock_reserve(base: CONFIG_LINUX_LINK_BASE,
110 __pa(_end) - CONFIG_LINUX_LINK_BASE);
111
112#ifdef CONFIG_BLK_DEV_INITRD
113 if (phys_initrd_size) {
114 memblock_reserve(base: phys_initrd_start, size: phys_initrd_size);
115 initrd_start = (unsigned long)__va(phys_initrd_start);
116 initrd_end = initrd_start + phys_initrd_size;
117 }
118#endif
119
120 early_init_fdt_reserve_self();
121 early_init_fdt_scan_reserved_mem();
122
123 memblock_dump_all();
124
125 /*----------------- node/zones setup --------------------------*/
126 max_zone_pfn[ZONE_NORMAL] = max_low_pfn;
127
128#ifdef CONFIG_HIGHMEM
129 /*
130 * On ARC (w/o PAE) HIGHMEM addresses are actually smaller (0 based)
131 * than addresses in normal aka low memory (0x8000_0000 based).
132 * Even with PAE, the huge peripheral space hole would waste a lot of
133 * mem with single contiguous mem_map[].
134 * Thus when HIGHMEM on ARC is enabled the memory map corresponding
135 * to the hole is freed and ARC specific version of pfn_valid()
136 * handles the hole in the memory map.
137 */
138
139 min_high_pfn = PFN_DOWN(high_mem_start);
140 max_high_pfn = PFN_DOWN(high_mem_start + high_mem_sz);
141
142 /*
143 * max_high_pfn should be ok here for both HIGHMEM and HIGHMEM+PAE.
144 * For HIGHMEM without PAE max_high_pfn should be less than
145 * min_low_pfn to guarantee that these two regions don't overlap.
146 * For PAE case highmem is greater than lowmem, so it is natural
147 * to use max_high_pfn.
148 *
149 * In both cases, holes should be handled by pfn_valid().
150 */
151 max_zone_pfn[ZONE_HIGHMEM] = max_high_pfn;
152
153 high_memory = (void *)(min_high_pfn << PAGE_SHIFT);
154
155 arch_pfn_offset = min(min_low_pfn, min_high_pfn);
156 kmap_init();
157
158#else /* CONFIG_HIGHMEM */
159 /* pfn_valid() uses this when FLATMEM=y and HIGHMEM=n */
160 max_mapnr = max_low_pfn - min_low_pfn;
161
162#endif /* CONFIG_HIGHMEM */
163
164 free_area_init(max_zone_pfn);
165}
166
167static void __init highmem_init(void)
168{
169#ifdef CONFIG_HIGHMEM
170 unsigned long tmp;
171
172 memblock_phys_free(high_mem_start, high_mem_sz);
173 for (tmp = min_high_pfn; tmp < max_high_pfn; tmp++)
174 free_highmem_page(pfn_to_page(tmp));
175#endif
176}
177
178/*
179 * mem_init - initializes memory
180 *
181 * Frees up bootmem
182 * Calculates and displays memory available/used
183 */
184void __init mem_init(void)
185{
186 memblock_free_all();
187 highmem_init();
188
189 BUILD_BUG_ON((PTRS_PER_PGD * sizeof(pgd_t)) > PAGE_SIZE);
190 BUILD_BUG_ON((PTRS_PER_PUD * sizeof(pud_t)) > PAGE_SIZE);
191 BUILD_BUG_ON((PTRS_PER_PMD * sizeof(pmd_t)) > PAGE_SIZE);
192 BUILD_BUG_ON((PTRS_PER_PTE * sizeof(pte_t)) > PAGE_SIZE);
193}
194
195#ifdef CONFIG_HIGHMEM
196int pfn_valid(unsigned long pfn)
197{
198 return (pfn >= min_high_pfn && pfn <= max_high_pfn) ||
199 (pfn >= min_low_pfn && pfn <= max_low_pfn);
200}
201EXPORT_SYMBOL(pfn_valid);
202#endif
203

source code of linux/arch/arc/mm/init.c