linux/arch/arc/mm/init.c
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   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/arcregs.h>
  19
  20pgd_t swapper_pg_dir[PTRS_PER_PGD] __aligned(PAGE_SIZE);
  21char empty_zero_page[PAGE_SIZE] __aligned(PAGE_SIZE);
  22EXPORT_SYMBOL(empty_zero_page);
  23
  24static const unsigned long low_mem_start = CONFIG_LINUX_RAM_BASE;
  25static unsigned long low_mem_sz;
  26
  27#ifdef CONFIG_HIGHMEM
  28static unsigned long min_high_pfn, max_high_pfn;
  29static phys_addr_t high_mem_start;
  30static phys_addr_t high_mem_sz;
  31unsigned long arch_pfn_offset;
  32EXPORT_SYMBOL(arch_pfn_offset);
  33#endif
  34
  35long __init arc_get_mem_sz(void)
  36{
  37        return low_mem_sz;
  38}
  39
  40/* User can over-ride above with "mem=nnn[KkMm]" in cmdline */
  41static int __init setup_mem_sz(char *str)
  42{
  43        low_mem_sz = memparse(str, NULL) & PAGE_MASK;
  44
  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));
  47
  48        return 0;
  49}
  50early_param("mem", setup_mem_sz);
  51
  52void __init early_init_dt_add_memory_arch(u64 base, u64 size)
  53{
  54        int in_use = 0;
  55
  56        if (!low_mem_sz) {
  57                if (base != low_mem_start)
  58                        panic("CONFIG_LINUX_RAM_BASE != DT memory { }");
  59
  60                low_mem_sz = size;
  61                in_use = 1;
  62                memblock_add_node(base, size, 0);
  63        } else {
  64#ifdef CONFIG_HIGHMEM
  65                high_mem_start = base;
  66                high_mem_sz = size;
  67                in_use = 1;
  68                memblock_add_node(base, size, 1);
  69                memblock_reserve(base, size);
  70#endif
  71        }
  72
  73        pr_info("Memory @ %llx [%lldM] %s\n",
  74                base, TO_MB(size), !in_use ? "Not used":"");
  75}
  76
  77bool arch_has_descending_max_zone_pfns(void)
  78{
  79        return !IS_ENABLED(CONFIG_ARC_HAS_PAE40);
  80}
  81
  82/*
  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
  86 * 3. zone setup
  87 */
  88void __init setup_arch_memory(void)
  89{
  90        unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 };
  91
  92        setup_initial_init_mm(_text, _etext, _edata, _end);
  93
  94        /* first page of system - kernel .vector starts here */
  95        min_low_pfn = virt_to_pfn(CONFIG_LINUX_RAM_BASE);
  96
  97        /* Last usable page of low mem */
  98        max_low_pfn = max_pfn = PFN_DOWN(low_mem_start + low_mem_sz);
  99
 100        /*------------- bootmem allocator setup -----------------------*/
 101
 102        /*
 103         * seed the bootmem allocator after any DT memory node parsing or
 104         * "mem=xxx" cmdline overrides have potentially updated @arc_mem_sz
 105         *
 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
 110         * the crash
 111         */
 112
 113        memblock_reserve(CONFIG_LINUX_LINK_BASE,
 114                         __pa(_end) - CONFIG_LINUX_LINK_BASE);
 115
 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;
 121        }
 122#endif
 123
 124        early_init_fdt_reserve_self();
 125        early_init_fdt_scan_reserved_mem();
 126
 127        memblock_dump_all();
 128
 129        /*----------------- node/zones setup --------------------------*/
 130        max_zone_pfn[ZONE_NORMAL] = max_low_pfn;
 131
 132#ifdef CONFIG_HIGHMEM
 133        /*
 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.
 141         */
 142
 143        min_high_pfn = PFN_DOWN(high_mem_start);
 144        max_high_pfn = PFN_DOWN(high_mem_start + high_mem_sz);
 145
 146        /*
 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.
 152         *
 153         * In both cases, holes should be handled by pfn_valid().
 154         */
 155        max_zone_pfn[ZONE_HIGHMEM] = max_high_pfn;
 156
 157        high_memory = (void *)(min_high_pfn << PAGE_SHIFT);
 158
 159        arch_pfn_offset = min(min_low_pfn, min_high_pfn);
 160        kmap_init();
 161
 162#else /* CONFIG_HIGHMEM */
 163        /* pfn_valid() uses this when FLATMEM=y and HIGHMEM=n */
 164        max_mapnr = max_low_pfn - min_low_pfn;
 165
 166#endif /* CONFIG_HIGHMEM */
 167
 168        free_area_init(max_zone_pfn);
 169}
 170
 171static void __init highmem_init(void)
 172{
 173#ifdef CONFIG_HIGHMEM
 174        unsigned long tmp;
 175
 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));
 179#endif
 180}
 181
 182/*
 183 * mem_init - initializes memory
 184 *
 185 * Frees up bootmem
 186 * Calculates and displays memory available/used
 187 */
 188void __init mem_init(void)
 189{
 190        memblock_free_all();
 191        highmem_init();
 192}
 193
 194#ifdef CONFIG_HIGHMEM
 195int pfn_valid(unsigned long pfn)
 196{
 197        return (pfn >= min_high_pfn && pfn <= max_high_pfn) ||
 198                (pfn >= min_low_pfn && pfn <= max_low_pfn);
 199}
 200EXPORT_SYMBOL(pfn_valid);
 201#endif
 202