arch/hexagon/mm/init.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Memory subsystem initialization for Hexagon
   4  *
   5  * Copyright (c) 2010-2013, The Linux Foundation. All rights reserved.
   6  */
   7
   8 #include <linux/init.h>
   9 #include <linux/mm.h>
  10 #include <linux/memblock.h>
  11 #include <asm/atomic.h>
  12 #include <linux/highmem.h>
  13 #include <asm/tlb.h>
  14 #include <asm/sections.h>
  15 #include <asm/vm_mmu.h>
  16
  17 /*
  18  * Define a startpg just past the end of the kernel image and a lastpg
  19  * that corresponds to the end of real or simulated platform memory.
  20  */
  21 #define bootmem_startpg (PFN_UP(((unsigned long) _end) - PAGE_OFFSET + PHYS_OFFSET))
  22
  23 unsigned long bootmem_lastpg;   /*  Should be set by platform code  */
  24 unsigned long __phys_offset;    /*  physical kernel offset >> 12  */
  25
  26 /*  Set as variable to limit PMD copies  */
  27 int max_kernel_seg = 0x303;
  28
  29 /*  indicate pfn's of high memory  */
  30 unsigned long highstart_pfn, highend_pfn;
  31
  32 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
  33
  34 /* Default cache attribute for newly created page tables */
  35 unsigned long _dflt_cache_att = CACHEDEF;
  36
  37 /*
  38  * The current "generation" of kernel map, which should not roll
  39  * over until Hell freezes over.  Actual bound in years needs to be
  40  * calculated to confirm.
  41  */
  42 DEFINE_SPINLOCK(kmap_gen_lock);
  43
  44 /*  checkpatch says don't init this to 0.  */
  45 unsigned long long kmap_generation;
  46
  47 /*
  48  * mem_init - initializes memory
  49  *
  50  * Frees up bootmem
  51  * Fixes up more stuff for HIGHMEM
  52  * Calculates and displays memory available/used
  53  */
  54 void __init mem_init(void)
  55 {
  56         /*  No idea where this is actually declared.  Seems to evade LXR.  */
  57         memblock_free_all();
  58         mem_init_print_info(NULL);
  59
  60         /*
  61          *  To-Do:  someone somewhere should wipe out the bootmem map
  62          *  after we're done?
  63          */
  64
  65         /*
  66          * This can be moved to some more virtual-memory-specific
  67          * initialization hook at some point.  Set the init_mm
  68          * descriptors "context" value to point to the initial
  69          * kernel segment table's physical address.
  70          */
  71         init_mm.context.ptbase = __pa(init_mm.pgd);
  72 }
  73
  74 void sync_icache_dcache(pte_t pte)
  75 {
  76         unsigned long addr;
  77         struct page *page;
  78
  79         page = pte_page(pte);
  80         addr = (unsigned long) page_address(page);
  81
  82         __vmcache_idsync(addr, PAGE_SIZE);
  83 }
  84
  85 /*
  86  * In order to set up page allocator "nodes",
  87  * somebody has to call free_area_init() for UMA.
  88  *
  89  * In this mode, we only have one pg_data_t
  90  * structure: contig_mem_data.
  91  */
  92 void __init paging_init(void)
  93 {
  94         unsigned long max_zone_pfn[MAX_NR_ZONES] = {0, };
  95
  96         /*
  97          *  This is not particularly well documented anywhere, but
  98          *  give ZONE_NORMAL all the memory, including the big holes
  99          *  left by the kernel+bootmem_map which are already left as reserved
 100          *  in the bootmem_map; free_area_init should see those bits and
 101          *  adjust accordingly.
 102          */
 103
 104         max_zone_pfn[ZONE_NORMAL] = max_low_pfn;
 105
 106         free_area_init(max_zone_pfn);  /*  sets up the zonelists and mem_map  */
 107
 108         /*
 109          * Start of high memory area.  Will probably need something more
 110          * fancy if we...  get more fancy.
 111          */
 112         high_memory = (void *)((bootmem_lastpg + 1) << PAGE_SHIFT);
 113 }
 114
 115 #ifndef DMA_RESERVE
 116 #define DMA_RESERVE             (4)
 117 #endif
 118
 119 #define DMA_CHUNKSIZE           (1<<22)
 120 #define DMA_RESERVED_BYTES      (DMA_RESERVE * DMA_CHUNKSIZE)
 121
 122 /*
 123  * Pick out the memory size.  We look for mem=size,
 124  * where size is "size[KkMm]"
 125  */
 126 static int __init early_mem(char *p)
 127 {
 128         unsigned long size;
 129         char *endp;
 130
 131         size = memparse(p, &endp);
 132
 133         bootmem_lastpg = PFN_DOWN(size);
 134
 135         return 0;
 136 }
 137 early_param("mem", early_mem);
 138
 139 size_t hexagon_coherent_pool_size = (size_t) (DMA_RESERVE << 22);
 140
 141 void __init setup_arch_memory(void)
 142 {
 143         /*  XXX Todo: this probably should be cleaned up  */
 144         u32 *segtable = (u32 *) &swapper_pg_dir[0];
 145         u32 *segtable_end;
 146
 147         /*
 148          * Set up boot memory allocator
 149          *
 150          * The Gorman book also talks about these functions.
 151          * This needs to change for highmem setups.
 152          */
 153
 154         /*  Prior to this, bootmem_lastpg is actually mem size  */
 155         bootmem_lastpg += ARCH_PFN_OFFSET;
 156
 157         /* Memory size needs to be a multiple of 16M */
 158         bootmem_lastpg = PFN_DOWN((bootmem_lastpg << PAGE_SHIFT) &
 159                 ~((BIG_KERNEL_PAGE_SIZE) - 1));
 160
 161         memblock_add(PHYS_OFFSET,
 162                      (bootmem_lastpg - ARCH_PFN_OFFSET) << PAGE_SHIFT);
 163
 164         /* Reserve kernel text/data/bss */
 165         memblock_reserve(PHYS_OFFSET,
 166                          (bootmem_startpg - ARCH_PFN_OFFSET) << PAGE_SHIFT);
 167         /*
 168          * Reserve the top DMA_RESERVE bytes of RAM for DMA (uncached)
 169          * memory allocation
 170          */
 171         max_low_pfn = bootmem_lastpg - PFN_DOWN(DMA_RESERVED_BYTES);
 172         min_low_pfn = ARCH_PFN_OFFSET;
 173         memblock_reserve(PFN_PHYS(max_low_pfn), DMA_RESERVED_BYTES);
 174
 175         printk(KERN_INFO "bootmem_startpg:  0x%08lx\n", bootmem_startpg);
 176         printk(KERN_INFO "bootmem_lastpg:  0x%08lx\n", bootmem_lastpg);
 177         printk(KERN_INFO "min_low_pfn:  0x%08lx\n", min_low_pfn);
 178         printk(KERN_INFO "max_low_pfn:  0x%08lx\n", max_low_pfn);
 179
 180         /*
 181          * The default VM page tables (will be) populated with
 182          * VA=PA+PAGE_OFFSET mapping.  We go in and invalidate entries
 183          * higher than what we have memory for.
 184          */
 185
 186         /*  this is pointer arithmetic; each entry covers 4MB  */
 187         segtable = segtable + (PAGE_OFFSET >> 22);
 188
 189         /*  this actually only goes to the end of the first gig  */
 190         segtable_end = segtable + (1<<(30-22));
 191
 192         /*
 193          * Move forward to the start of empty pages; take into account
 194          * phys_offset shift.
 195          */
 196
 197         segtable += (bootmem_lastpg-ARCH_PFN_OFFSET)>>(22-PAGE_SHIFT);
 198         {
 199                 int i;
 200
 201                 for (i = 1 ; i <= DMA_RESERVE ; i++)
 202                         segtable[-i] = ((segtable[-i] & __HVM_PTE_PGMASK_4MB)
 203                                 | __HVM_PTE_R | __HVM_PTE_W | __HVM_PTE_X
 204                                 | __HEXAGON_C_UNC << 6
 205                                 | __HVM_PDE_S_4MB);
 206         }
 207
 208         printk(KERN_INFO "clearing segtable from %p to %p\n", segtable,
 209                 segtable_end);
 210         while (segtable < (segtable_end-8))
 211                 *(segtable++) = __HVM_PDE_S_INVALID;
 212         /* stop the pointer at the device I/O 4MB page  */
 213
 214         printk(KERN_INFO "segtable = %p (should be equal to _K_io_map)\n",
 215                 segtable);
 216
 217 #if 0
 218         /*  Other half of the early device table from vm_init_segtable. */
 219         printk(KERN_INFO "&_K_init_devicetable = 0x%08x\n",
 220                 (unsigned long) _K_init_devicetable-PAGE_OFFSET);
 221         *segtable = ((u32) (unsigned long) _K_init_devicetable-PAGE_OFFSET) |
 222                 __HVM_PDE_S_4KB;
 223         printk(KERN_INFO "*segtable = 0x%08x\n", *segtable);
 224 #endif
 225
 226         /*
 227          *  The bootmem allocator seemingly just lives to feed memory
 228          *  to the paging system
 229          */
 230         printk(KERN_INFO "PAGE_SIZE=%lu\n", PAGE_SIZE);
 231         paging_init();  /*  See Gorman Book, 2.3  */
 232
 233         /*
 234          *  At this point, the page allocator is kind of initialized, but
 235          *  apparently no pages are available (just like with the bootmem
 236          *  allocator), and need to be freed themselves via mem_init(),
 237          *  which is called by start_kernel() later on in the process
 238          */
 239 }