arch/arc/mm/init.c

   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
  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 */
  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
  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  */
  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
 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  */
 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
 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