arch/riscv/mm/init.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2012 Regents of the University of California
   4  */
   5
   6 #include <linux/init.h>
   7 #include <linux/mm.h>
   8 #include <linux/memblock.h>
   9 #include <linux/initrd.h>
  10 #include <linux/swap.h>
  11 #include <linux/sizes.h>
  12 #include <linux/of_fdt.h>
  13
  14 #include <asm/fixmap.h>
  15 #include <asm/tlbflush.h>
  16 #include <asm/sections.h>
  17 #include <asm/pgtable.h>
  18 #include <asm/io.h>
  19
  20 unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)]
  21                                                         __page_aligned_bss;
  22 EXPORT_SYMBOL(empty_zero_page);
  23
  24 static void __init zone_sizes_init(void)
  25 {
  26         unsigned long max_zone_pfns[MAX_NR_ZONES] = { 0, };
  27
  28 #ifdef CONFIG_ZONE_DMA32
  29         max_zone_pfns[ZONE_DMA32] = PFN_DOWN(min(4UL * SZ_1G,
  30                         (unsigned long) PFN_PHYS(max_low_pfn)));
  31 #endif
  32         max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
  33
  34         free_area_init_nodes(max_zone_pfns);
  35 }
  36
  37 void setup_zero_page(void)
  38 {
  39         memset((void *)empty_zero_page, 0, PAGE_SIZE);
  40 }
  41
  42 void __init paging_init(void)
  43 {
  44         setup_zero_page();
  45         local_flush_tlb_all();
  46         zone_sizes_init();
  47 }
  48
  49 void __init mem_init(void)
  50 {
  51 #ifdef CONFIG_FLATMEM
  52         BUG_ON(!mem_map);
  53 #endif /* CONFIG_FLATMEM */
  54
  55         high_memory = (void *)(__va(PFN_PHYS(max_low_pfn)));
  56         memblock_free_all();
  57
  58         mem_init_print_info(NULL);
  59 }
  60
  61 #ifdef CONFIG_BLK_DEV_INITRD
  62 static void __init setup_initrd(void)
  63 {
  64         unsigned long size;
  65
  66         if (initrd_start >= initrd_end) {
  67                 pr_info("initrd not found or empty");
  68                 goto disable;
  69         }
  70         if (__pa(initrd_end) > PFN_PHYS(max_low_pfn)) {
  71                 pr_err("initrd extends beyond end of memory");
  72                 goto disable;
  73         }
  74
  75         size = initrd_end - initrd_start;
  76         memblock_reserve(__pa(initrd_start), size);
  77         initrd_below_start_ok = 1;
  78
  79         pr_info("Initial ramdisk at: 0x%p (%lu bytes)\n",
  80                 (void *)(initrd_start), size);
  81         return;
  82 disable:
  83         pr_cont(" - disabling initrd\n");
  84         initrd_start = 0;
  85         initrd_end = 0;
  86 }
  87
  88 void __init free_initrd_mem(unsigned long start, unsigned long end)
  89 {
  90         free_reserved_area((void *)start, (void *)end, -1, "initrd");
  91 }
  92 #endif /* CONFIG_BLK_DEV_INITRD */
  93
  94 void __init setup_bootmem(void)
  95 {
  96         struct memblock_region *reg;
  97         phys_addr_t mem_size = 0;
  98
  99         /* Find the memory region containing the kernel */
 100         for_each_memblock(memory, reg) {
 101                 phys_addr_t vmlinux_end = __pa(_end);
 102                 phys_addr_t end = reg->base + reg->size;
 103
 104                 if (reg->base <= vmlinux_end && vmlinux_end <= end) {
 105                         /*
 106                          * Reserve from the start of the region to the end of
 107                          * the kernel
 108                          */
 109                         memblock_reserve(reg->base, vmlinux_end - reg->base);
 110                         mem_size = min(reg->size, (phys_addr_t)-PAGE_OFFSET);
 111
 112                         /*
 113                          * Remove memblock from the end of usable area to the
 114                          * end of region
 115                          */
 116                         if (reg->base + mem_size < end)
 117                                 memblock_remove(reg->base + mem_size,
 118                                                 end - reg->base - mem_size);
 119                 }
 120         }
 121         BUG_ON(mem_size == 0);
 122
 123         set_max_mapnr(PFN_DOWN(mem_size));
 124         max_low_pfn = PFN_DOWN(memblock_end_of_DRAM());
 125
 126 #ifdef CONFIG_BLK_DEV_INITRD
 127         setup_initrd();
 128 #endif /* CONFIG_BLK_DEV_INITRD */
 129
 130         early_init_fdt_reserve_self();
 131         early_init_fdt_scan_reserved_mem();
 132         memblock_allow_resize();
 133         memblock_dump_all();
 134
 135         for_each_memblock(memory, reg) {
 136                 unsigned long start_pfn = memblock_region_memory_base_pfn(reg);
 137                 unsigned long end_pfn = memblock_region_memory_end_pfn(reg);
 138
 139                 memblock_set_node(PFN_PHYS(start_pfn),
 140                                   PFN_PHYS(end_pfn - start_pfn),
 141                                   &memblock.memory, 0);
 142         }
 143 }
 144
 145 unsigned long va_pa_offset;
 146 EXPORT_SYMBOL(va_pa_offset);
 147 unsigned long pfn_base;
 148 EXPORT_SYMBOL(pfn_base);
 149
 150 pgd_t swapper_pg_dir[PTRS_PER_PGD] __page_aligned_bss;
 151 pgd_t trampoline_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);
 152
 153 #ifndef __PAGETABLE_PMD_FOLDED
 154 #define NUM_SWAPPER_PMDS ((uintptr_t)-PAGE_OFFSET >> PGDIR_SHIFT)
 155 pmd_t swapper_pmd[PTRS_PER_PMD*((-PAGE_OFFSET)/PGDIR_SIZE)] __page_aligned_bss;
 156 pmd_t trampoline_pmd[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);
 157 pmd_t fixmap_pmd[PTRS_PER_PMD] __page_aligned_bss;
 158 #endif
 159
 160 pte_t fixmap_pte[PTRS_PER_PTE] __page_aligned_bss;
 161
 162 void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot)
 163 {
 164         unsigned long addr = __fix_to_virt(idx);
 165         pte_t *ptep;
 166
 167         BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses);
 168
 169         ptep = &fixmap_pte[pte_index(addr)];
 170
 171         if (pgprot_val(prot)) {
 172                 set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, prot));
 173         } else {
 174                 pte_clear(&init_mm, addr, ptep);
 175                 local_flush_tlb_page(addr);
 176         }
 177 }
 178
 179 /*
 180  * setup_vm() is called from head.S with MMU-off.
 181  *
 182  * Following requirements should be honoured for setup_vm() to work
 183  * correctly:
 184  * 1) It should use PC-relative addressing for accessing kernel symbols.
 185  *    To achieve this we always use GCC cmodel=medany.
 186  * 2) The compiler instrumentation for FTRACE will not work for setup_vm()
 187  *    so disable compiler instrumentation when FTRACE is enabled.
 188  *
 189  * Currently, the above requirements are honoured by using custom CFLAGS
 190  * for init.o in mm/Makefile.
 191  */
 192
 193 #ifndef __riscv_cmodel_medany
 194 #error "setup_vm() is called from head.S before relocate so it should "
 195         "not use absolute addressing."
 196 #endif
 197
 198 asmlinkage void __init setup_vm(void)
 199 {
 200         extern char _start;
 201         uintptr_t i;
 202         uintptr_t pa = (uintptr_t) &_start;
 203         pgprot_t prot = __pgprot(pgprot_val(PAGE_KERNEL) | _PAGE_EXEC);
 204
 205         va_pa_offset = PAGE_OFFSET - pa;
 206         pfn_base = PFN_DOWN(pa);
 207
 208         /* Sanity check alignment and size */
 209         BUG_ON((PAGE_OFFSET % PGDIR_SIZE) != 0);
 210         BUG_ON((pa % (PAGE_SIZE * PTRS_PER_PTE)) != 0);
 211
 212 #ifndef __PAGETABLE_PMD_FOLDED
 213         trampoline_pg_dir[(PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD] =
 214                 pfn_pgd(PFN_DOWN((uintptr_t)trampoline_pmd),
 215                         __pgprot(_PAGE_TABLE));
 216         trampoline_pmd[0] = pfn_pmd(PFN_DOWN(pa), prot);
 217
 218         for (i = 0; i < (-PAGE_OFFSET)/PGDIR_SIZE; ++i) {
 219                 size_t o = (PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD + i;
 220
 221                 swapper_pg_dir[o] =
 222                         pfn_pgd(PFN_DOWN((uintptr_t)swapper_pmd) + i,
 223                                 __pgprot(_PAGE_TABLE));
 224         }
 225         for (i = 0; i < ARRAY_SIZE(swapper_pmd); i++)
 226                 swapper_pmd[i] = pfn_pmd(PFN_DOWN(pa + i * PMD_SIZE), prot);
 227
 228         swapper_pg_dir[(FIXADDR_START >> PGDIR_SHIFT) % PTRS_PER_PGD] =
 229                 pfn_pgd(PFN_DOWN((uintptr_t)fixmap_pmd),
 230                                 __pgprot(_PAGE_TABLE));
 231         fixmap_pmd[(FIXADDR_START >> PMD_SHIFT) % PTRS_PER_PMD] =
 232                 pfn_pmd(PFN_DOWN((uintptr_t)fixmap_pte),
 233                                 __pgprot(_PAGE_TABLE));
 234 #else
 235         trampoline_pg_dir[(PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD] =
 236                 pfn_pgd(PFN_DOWN(pa), prot);
 237
 238         for (i = 0; i < (-PAGE_OFFSET)/PGDIR_SIZE; ++i) {
 239                 size_t o = (PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD + i;
 240
 241                 swapper_pg_dir[o] =
 242                         pfn_pgd(PFN_DOWN(pa + i * PGDIR_SIZE), prot);
 243         }
 244
 245         swapper_pg_dir[(FIXADDR_START >> PGDIR_SHIFT) % PTRS_PER_PGD] =
 246                 pfn_pgd(PFN_DOWN((uintptr_t)fixmap_pte),
 247                                 __pgprot(_PAGE_TABLE));
 248 #endif
 249 }