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