arch/riscv/mm/init.c

   1 /*
   2  * Copyright (C) 2012 Regents of the University of California
   3  *
   4  *   This program is free software; you can redistribute it and/or
   5  *   modify it under the terms of the GNU General Public License
   6  *   as published by the Free Software Foundation, version 2.
   7  *
   8  *   This program is distributed in the hope that it will be useful,
   9  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  *   GNU General Public License for more details.
  12  */
  13
  14 #include <linux/init.h>
  15 #include <linux/mm.h>
  16 #include <linux/memblock.h>
  17 #include <linux/initrd.h>
  18 #include <linux/swap.h>
  19 #include <linux/sizes.h>
  20 #include <linux/of_fdt.h>
  21
  22 #include <asm/fixmap.h>
  23 #include <asm/tlbflush.h>
  24 #include <asm/sections.h>
  25 #include <asm/pgtable.h>
  26 #include <asm/io.h>
  27
  28 unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)]
  29                                                         __page_aligned_bss;
  30 EXPORT_SYMBOL(empty_zero_page);
  31
  32 static void __init zone_sizes_init(void)
  33 {
  34         unsigned long max_zone_pfns[MAX_NR_ZONES] = { 0, };
  35
  36 #ifdef CONFIG_ZONE_DMA32
  37         max_zone_pfns[ZONE_DMA32] = PFN_DOWN(min(4UL * SZ_1G,
  38                         (unsigned long) PFN_PHYS(max_low_pfn)));
  39 #endif
  40         max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
  41
  42         free_area_init_nodes(max_zone_pfns);
  43 }
  44
  45 void setup_zero_page(void)
  46 {
  47         memset((void *)empty_zero_page, 0, PAGE_SIZE);
  48 }
  49
  50 void __init paging_init(void)
  51 {
  52         setup_zero_page();
  53         local_flush_tlb_all();
  54         zone_sizes_init();
  55 }
  56
  57 void __init mem_init(void)
  58 {
  59 #ifdef CONFIG_FLATMEM
  60         BUG_ON(!mem_map);
  61 #endif /* CONFIG_FLATMEM */
  62
  63         high_memory = (void *)(__va(PFN_PHYS(max_low_pfn)));
  64         memblock_free_all();
  65
  66         mem_init_print_info(NULL);
  67 }
  68
  69 void free_initmem(void)
  70 {
  71         free_initmem_default(0);
  72 }
  73
  74 #ifdef CONFIG_BLK_DEV_INITRD
  75 static void __init setup_initrd(void)
  76 {
  77         unsigned long size;
  78
  79         if (initrd_start >= initrd_end) {
  80                 pr_info("initrd not found or empty");
  81                 goto disable;
  82         }
  83         if (__pa(initrd_end) > PFN_PHYS(max_low_pfn)) {
  84                 pr_err("initrd extends beyond end of memory");
  85                 goto disable;
  86         }
  87
  88         size = initrd_end - initrd_start;
  89         memblock_reserve(__pa(initrd_start), size);
  90         initrd_below_start_ok = 1;
  91
  92         pr_info("Initial ramdisk at: 0x%p (%lu bytes)\n",
  93                 (void *)(initrd_start), size);
  94         return;
  95 disable:
  96         pr_cont(" - disabling initrd\n");
  97         initrd_start = 0;
  98         initrd_end = 0;
  99 }
 100
 101 void __init free_initrd_mem(unsigned long start, unsigned long end)
 102 {
 103         free_reserved_area((void *)start, (void *)end, -1, "initrd");
 104 }
 105 #endif /* CONFIG_BLK_DEV_INITRD */
 106
 107 void __init setup_bootmem(void)
 108 {
 109         struct memblock_region *reg;
 110         phys_addr_t mem_size = 0;
 111
 112         /* Find the memory region containing the kernel */
 113         for_each_memblock(memory, reg) {
 114                 phys_addr_t vmlinux_end = __pa(_end);
 115                 phys_addr_t end = reg->base + reg->size;
 116
 117                 if (reg->base <= vmlinux_end && vmlinux_end <= end) {
 118                         /*
 119                          * Reserve from the start of the region to the end of
 120                          * the kernel
 121                          */
 122                         memblock_reserve(reg->base, vmlinux_end - reg->base);
 123                         mem_size = min(reg->size, (phys_addr_t)-PAGE_OFFSET);
 124
 125                         /*
 126                          * Remove memblock from the end of usable area to the
 127                          * end of region
 128                          */
 129                         if (reg->base + mem_size < end)
 130                                 memblock_remove(reg->base + mem_size,
 131                                                 end - reg->base - mem_size);
 132                 }
 133         }
 134         BUG_ON(mem_size == 0);
 135
 136         set_max_mapnr(PFN_DOWN(mem_size));
 137         max_low_pfn = PFN_DOWN(memblock_end_of_DRAM());
 138
 139 #ifdef CONFIG_BLK_DEV_INITRD
 140         setup_initrd();
 141 #endif /* CONFIG_BLK_DEV_INITRD */
 142
 143         early_init_fdt_reserve_self();
 144         early_init_fdt_scan_reserved_mem();
 145         memblock_allow_resize();
 146         memblock_dump_all();
 147
 148         for_each_memblock(memory, reg) {
 149                 unsigned long start_pfn = memblock_region_memory_base_pfn(reg);
 150                 unsigned long end_pfn = memblock_region_memory_end_pfn(reg);
 151
 152                 memblock_set_node(PFN_PHYS(start_pfn),
 153                                   PFN_PHYS(end_pfn - start_pfn),
 154                                   &memblock.memory, 0);
 155         }
 156 }
 157
 158 unsigned long va_pa_offset;
 159 EXPORT_SYMBOL(va_pa_offset);
 160 unsigned long pfn_base;
 161 EXPORT_SYMBOL(pfn_base);
 162
 163 pgd_t swapper_pg_dir[PTRS_PER_PGD] __page_aligned_bss;
 164 pgd_t trampoline_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);
 165
 166 #ifndef __PAGETABLE_PMD_FOLDED
 167 #define NUM_SWAPPER_PMDS ((uintptr_t)-PAGE_OFFSET >> PGDIR_SHIFT)
 168 pmd_t swapper_pmd[PTRS_PER_PMD*((-PAGE_OFFSET)/PGDIR_SIZE)] __page_aligned_bss;
 169 pmd_t trampoline_pmd[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);
 170 pmd_t fixmap_pmd[PTRS_PER_PMD] __page_aligned_bss;
 171 #endif
 172
 173 pte_t fixmap_pte[PTRS_PER_PTE] __page_aligned_bss;
 174
 175 void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot)
 176 {
 177         unsigned long addr = __fix_to_virt(idx);
 178         pte_t *ptep;
 179
 180         BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses);
 181
 182         ptep = &fixmap_pte[pte_index(addr)];
 183
 184         if (pgprot_val(prot)) {
 185                 set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, prot));
 186         } else {
 187                 pte_clear(&init_mm, addr, ptep);
 188                 local_flush_tlb_page(addr);
 189         }
 190 }
 191
 192 /*
 193  * setup_vm() is called from head.S with MMU-off.
 194  *
 195  * Following requirements should be honoured for setup_vm() to work
 196  * correctly:
 197  * 1) It should use PC-relative addressing for accessing kernel symbols.
 198  *    To achieve this we always use GCC cmodel=medany.
 199  * 2) The compiler instrumentation for FTRACE will not work for setup_vm()
 200  *    so disable compiler instrumentation when FTRACE is enabled.
 201  *
 202  * Currently, the above requirements are honoured by using custom CFLAGS
 203  * for init.o in mm/Makefile.
 204  */
 205
 206 #ifndef __riscv_cmodel_medany
 207 #error "setup_vm() is called from head.S before relocate so it should "
 208         "not use absolute addressing."
 209 #endif
 210
 211 asmlinkage void __init setup_vm(void)
 212 {
 213         extern char _start;
 214         uintptr_t i;
 215         uintptr_t pa = (uintptr_t) &_start;
 216         pgprot_t prot = __pgprot(pgprot_val(PAGE_KERNEL) | _PAGE_EXEC);
 217
 218         va_pa_offset = PAGE_OFFSET - pa;
 219         pfn_base = PFN_DOWN(pa);
 220
 221         /* Sanity check alignment and size */
 222         BUG_ON((PAGE_OFFSET % PGDIR_SIZE) != 0);
 223         BUG_ON((pa % (PAGE_SIZE * PTRS_PER_PTE)) != 0);
 224
 225 #ifndef __PAGETABLE_PMD_FOLDED
 226         trampoline_pg_dir[(PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD] =
 227                 pfn_pgd(PFN_DOWN((uintptr_t)trampoline_pmd),
 228                         __pgprot(_PAGE_TABLE));
 229         trampoline_pmd[0] = pfn_pmd(PFN_DOWN(pa), prot);
 230
 231         for (i = 0; i < (-PAGE_OFFSET)/PGDIR_SIZE; ++i) {
 232                 size_t o = (PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD + i;
 233
 234                 swapper_pg_dir[o] =
 235                         pfn_pgd(PFN_DOWN((uintptr_t)swapper_pmd) + i,
 236                                 __pgprot(_PAGE_TABLE));
 237         }
 238         for (i = 0; i < ARRAY_SIZE(swapper_pmd); i++)
 239                 swapper_pmd[i] = pfn_pmd(PFN_DOWN(pa + i * PMD_SIZE), prot);
 240
 241         swapper_pg_dir[(FIXADDR_START >> PGDIR_SHIFT) % PTRS_PER_PGD] =
 242                 pfn_pgd(PFN_DOWN((uintptr_t)fixmap_pmd),
 243                                 __pgprot(_PAGE_TABLE));
 244         fixmap_pmd[(FIXADDR_START >> PMD_SHIFT) % PTRS_PER_PMD] =
 245                 pfn_pmd(PFN_DOWN((uintptr_t)fixmap_pte),
 246                                 __pgprot(_PAGE_TABLE));
 247 #else
 248         trampoline_pg_dir[(PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD] =
 249                 pfn_pgd(PFN_DOWN(pa), prot);
 250
 251         for (i = 0; i < (-PAGE_OFFSET)/PGDIR_SIZE; ++i) {
 252                 size_t o = (PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD + i;
 253
 254                 swapper_pg_dir[o] =
 255                         pfn_pgd(PFN_DOWN(pa + i * PGDIR_SIZE), prot);
 256         }
 257
 258         swapper_pg_dir[(FIXADDR_START >> PGDIR_SHIFT) % PTRS_PER_PGD] =
 259                 pfn_pgd(PFN_DOWN((uintptr_t)fixmap_pte),
 260                                 __pgprot(_PAGE_TABLE));
 261 #endif
 262 }