xref: /openbmc/linux/arch/arc/mm/init.c (revision 4d369680)
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 
21 pgd_t swapper_pg_dir[PTRS_PER_PGD] __aligned(PAGE_SIZE);
22 char empty_zero_page[PAGE_SIZE] __aligned(PAGE_SIZE);
23 EXPORT_SYMBOL(empty_zero_page);
24 
25 static const unsigned long low_mem_start = CONFIG_LINUX_RAM_BASE;
26 static unsigned long low_mem_sz;
27 
28 #ifdef CONFIG_HIGHMEM
29 static unsigned long min_high_pfn, max_high_pfn;
30 static phys_addr_t high_mem_start;
31 static phys_addr_t high_mem_sz;
32 unsigned long arch_pfn_offset;
33 EXPORT_SYMBOL(arch_pfn_offset);
34 #endif
35 
arc_get_mem_sz(void)36 long __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 */
setup_mem_sz(char * str)42 static int __init setup_mem_sz(char *str)
43 {
44 	low_mem_sz = memparse(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 }
51 early_param("mem", setup_mem_sz);
52 
early_init_dt_add_memory_arch(u64 base,u64 size)53 void __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("CONFIG_LINUX_RAM_BASE != DT memory { }");
60 
61 		low_mem_sz = size;
62 		in_use = 1;
63 		memblock_add_node(base, size, 0, 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  */
setup_arch_memory(void)84 void __init setup_arch_memory(void)
85 {
86 	unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 };
87 
88 	setup_initial_init_mm(_text, _etext, _edata, _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(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(phys_initrd_start, 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 
highmem_init(void)167 static 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  */
mem_init(void)184 void __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
pfn_valid(unsigned long pfn)196 int 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 }
201 EXPORT_SYMBOL(pfn_valid);
202 #endif
203