1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
6 #include <linux/kernel.h>
8 #include <linux/memblock.h>
9 #ifdef CONFIG_BLK_DEV_INITRD
10 #include <linux/initrd.h>
12 #include <linux/of_fdt.h>
13 #include <linux/swap.h>
14 #include <linux/module.h>
15 #include <linux/highmem.h>
17 #include <asm/sections.h>
18 #include <asm/arcregs.h>
20 pgd_t swapper_pg_dir[PTRS_PER_PGD] __aligned(PAGE_SIZE);
21 char empty_zero_page[PAGE_SIZE] __aligned(PAGE_SIZE);
22 EXPORT_SYMBOL(empty_zero_page);
24 static const unsigned long low_mem_start = CONFIG_LINUX_RAM_BASE;
25 static unsigned long low_mem_sz;
28 static unsigned long min_high_pfn, max_high_pfn;
29 static phys_addr_t high_mem_start;
30 static phys_addr_t high_mem_sz;
31 unsigned long arch_pfn_offset;
32 EXPORT_SYMBOL(arch_pfn_offset);
35 long __init arc_get_mem_sz(void)
40 /* User can over-ride above with "mem=nnn[KkMm]" in cmdline */
41 static int __init setup_mem_sz(char *str)
43 low_mem_sz = memparse(str, NULL) & PAGE_MASK;
45 /* early console might not be setup yet - it will show up later */
46 pr_info("\"mem=%s\": mem sz set to %ldM\n", str, TO_MB(low_mem_sz));
50 early_param("mem", setup_mem_sz);
52 void __init early_init_dt_add_memory_arch(u64 base, u64 size)
57 if (base != low_mem_start)
58 panic("CONFIG_LINUX_RAM_BASE != DT memory { }");
62 memblock_add_node(base, size, 0);
65 high_mem_start = base;
68 memblock_add_node(base, size, 1);
69 memblock_reserve(base, size);
73 pr_info("Memory @ %llx [%lldM] %s\n",
74 base, TO_MB(size), !in_use ? "Not used":"");
77 bool arch_has_descending_max_zone_pfns(void)
79 return !IS_ENABLED(CONFIG_ARC_HAS_PAE40);
83 * First memory setup routine called from setup_arch()
84 * 1. setup swapper's mm @init_mm
85 * 2. Count the pages we have and setup bootmem allocator
88 void __init setup_arch_memory(void)
90 unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 };
92 setup_initial_init_mm(_text, _etext, _edata, _end);
94 /* first page of system - kernel .vector starts here */
95 min_low_pfn = virt_to_pfn(CONFIG_LINUX_RAM_BASE);
97 /* Last usable page of low mem */
98 max_low_pfn = max_pfn = PFN_DOWN(low_mem_start + low_mem_sz);
100 /*------------- bootmem allocator setup -----------------------*/
103 * seed the bootmem allocator after any DT memory node parsing or
104 * "mem=xxx" cmdline overrides have potentially updated @arc_mem_sz
106 * Only low mem is added, otherwise we have crashes when allocating
107 * mem_map[] itself. NO_BOOTMEM allocates mem_map[] at the end of
108 * avail memory, ending in highmem with a > 32-bit address. However
109 * it then tries to memset it with a truncaed 32-bit handle, causing
113 memblock_reserve(CONFIG_LINUX_LINK_BASE,
114 __pa(_end) - CONFIG_LINUX_LINK_BASE);
116 #ifdef CONFIG_BLK_DEV_INITRD
117 if (phys_initrd_size) {
118 memblock_reserve(phys_initrd_start, phys_initrd_size);
119 initrd_start = (unsigned long)__va(phys_initrd_start);
120 initrd_end = initrd_start + phys_initrd_size;
124 early_init_fdt_reserve_self();
125 early_init_fdt_scan_reserved_mem();
129 /*----------------- node/zones setup --------------------------*/
130 max_zone_pfn[ZONE_NORMAL] = max_low_pfn;
132 #ifdef CONFIG_HIGHMEM
134 * On ARC (w/o PAE) HIGHMEM addresses are actually smaller (0 based)
135 * than addresses in normal aka low memory (0x8000_0000 based).
136 * Even with PAE, the huge peripheral space hole would waste a lot of
137 * mem with single contiguous mem_map[].
138 * Thus when HIGHMEM on ARC is enabled the memory map corresponding
139 * to the hole is freed and ARC specific version of pfn_valid()
140 * handles the hole in the memory map.
143 min_high_pfn = PFN_DOWN(high_mem_start);
144 max_high_pfn = PFN_DOWN(high_mem_start + high_mem_sz);
147 * max_high_pfn should be ok here for both HIGHMEM and HIGHMEM+PAE.
148 * For HIGHMEM without PAE max_high_pfn should be less than
149 * min_low_pfn to guarantee that these two regions don't overlap.
150 * For PAE case highmem is greater than lowmem, so it is natural
151 * to use max_high_pfn.
153 * In both cases, holes should be handled by pfn_valid().
155 max_zone_pfn[ZONE_HIGHMEM] = max_high_pfn;
157 high_memory = (void *)(min_high_pfn << PAGE_SHIFT);
159 arch_pfn_offset = min(min_low_pfn, min_high_pfn);
162 #else /* CONFIG_HIGHMEM */
163 /* pfn_valid() uses this when FLATMEM=y and HIGHMEM=n */
164 max_mapnr = max_low_pfn - min_low_pfn;
166 #endif /* CONFIG_HIGHMEM */
168 free_area_init(max_zone_pfn);
171 static void __init highmem_init(void)
173 #ifdef CONFIG_HIGHMEM
176 memblock_free(high_mem_start, high_mem_sz);
177 for (tmp = min_high_pfn; tmp < max_high_pfn; tmp++)
178 free_highmem_page(pfn_to_page(tmp));
183 * mem_init - initializes memory
186 * Calculates and displays memory available/used
188 void __init mem_init(void)
194 #ifdef CONFIG_HIGHMEM
195 int pfn_valid(unsigned long pfn)
197 return (pfn >= min_high_pfn && pfn <= max_high_pfn) ||
198 (pfn >= min_low_pfn && pfn <= max_low_pfn);
200 EXPORT_SYMBOL(pfn_valid);