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 /* 75 * free_initrd_mem - frees... initrd memory. 76 * @start - start of init memory 77 * @end - end of init memory 78 * 79 * Apparently has to be passed the address of the initrd memory. 80 * 81 * Wrapped by #ifdef CONFIG_BLKDEV_INITRD 82 */ 83 void free_initrd_mem(unsigned long start, unsigned long end) 84 { 85 } 86 87 void sync_icache_dcache(pte_t pte) 88 { 89 unsigned long addr; 90 struct page *page; 91 92 page = pte_page(pte); 93 addr = (unsigned long) page_address(page); 94 95 __vmcache_idsync(addr, PAGE_SIZE); 96 } 97 98 /* 99 * In order to set up page allocator "nodes", 100 * somebody has to call free_area_init() for UMA. 101 * 102 * In this mode, we only have one pg_data_t 103 * structure: contig_mem_data. 104 */ 105 void __init paging_init(void) 106 { 107 unsigned long zones_sizes[MAX_NR_ZONES] = {0, }; 108 109 /* 110 * This is not particularly well documented anywhere, but 111 * give ZONE_NORMAL all the memory, including the big holes 112 * left by the kernel+bootmem_map which are already left as reserved 113 * in the bootmem_map; free_area_init should see those bits and 114 * adjust accordingly. 115 */ 116 117 zones_sizes[ZONE_NORMAL] = max_low_pfn; 118 119 free_area_init(zones_sizes); /* sets up the zonelists and mem_map */ 120 121 /* 122 * Start of high memory area. Will probably need something more 123 * fancy if we... get more fancy. 124 */ 125 high_memory = (void *)((bootmem_lastpg + 1) << PAGE_SHIFT); 126 } 127 128 #ifndef DMA_RESERVE 129 #define DMA_RESERVE (4) 130 #endif 131 132 #define DMA_CHUNKSIZE (1<<22) 133 #define DMA_RESERVED_BYTES (DMA_RESERVE * DMA_CHUNKSIZE) 134 135 /* 136 * Pick out the memory size. We look for mem=size, 137 * where size is "size[KkMm]" 138 */ 139 static int __init early_mem(char *p) 140 { 141 unsigned long size; 142 char *endp; 143 144 size = memparse(p, &endp); 145 146 bootmem_lastpg = PFN_DOWN(size); 147 148 return 0; 149 } 150 early_param("mem", early_mem); 151 152 size_t hexagon_coherent_pool_size = (size_t) (DMA_RESERVE << 22); 153 154 void __init setup_arch_memory(void) 155 { 156 /* XXX Todo: this probably should be cleaned up */ 157 u32 *segtable = (u32 *) &swapper_pg_dir[0]; 158 u32 *segtable_end; 159 160 /* 161 * Set up boot memory allocator 162 * 163 * The Gorman book also talks about these functions. 164 * This needs to change for highmem setups. 165 */ 166 167 /* Prior to this, bootmem_lastpg is actually mem size */ 168 bootmem_lastpg += ARCH_PFN_OFFSET; 169 170 /* Memory size needs to be a multiple of 16M */ 171 bootmem_lastpg = PFN_DOWN((bootmem_lastpg << PAGE_SHIFT) & 172 ~((BIG_KERNEL_PAGE_SIZE) - 1)); 173 174 memblock_add(PHYS_OFFSET, 175 (bootmem_lastpg - ARCH_PFN_OFFSET) << PAGE_SHIFT); 176 177 /* Reserve kernel text/data/bss */ 178 memblock_reserve(PHYS_OFFSET, 179 (bootmem_startpg - ARCH_PFN_OFFSET) << PAGE_SHIFT); 180 /* 181 * Reserve the top DMA_RESERVE bytes of RAM for DMA (uncached) 182 * memory allocation 183 */ 184 max_low_pfn = bootmem_lastpg - PFN_DOWN(DMA_RESERVED_BYTES); 185 min_low_pfn = ARCH_PFN_OFFSET; 186 memblock_reserve(PFN_PHYS(max_low_pfn), DMA_RESERVED_BYTES); 187 188 printk(KERN_INFO "bootmem_startpg: 0x%08lx\n", bootmem_startpg); 189 printk(KERN_INFO "bootmem_lastpg: 0x%08lx\n", bootmem_lastpg); 190 printk(KERN_INFO "min_low_pfn: 0x%08lx\n", min_low_pfn); 191 printk(KERN_INFO "max_low_pfn: 0x%08lx\n", max_low_pfn); 192 193 /* 194 * The default VM page tables (will be) populated with 195 * VA=PA+PAGE_OFFSET mapping. We go in and invalidate entries 196 * higher than what we have memory for. 197 */ 198 199 /* this is pointer arithmetic; each entry covers 4MB */ 200 segtable = segtable + (PAGE_OFFSET >> 22); 201 202 /* this actually only goes to the end of the first gig */ 203 segtable_end = segtable + (1<<(30-22)); 204 205 /* 206 * Move forward to the start of empty pages; take into account 207 * phys_offset shift. 208 */ 209 210 segtable += (bootmem_lastpg-ARCH_PFN_OFFSET)>>(22-PAGE_SHIFT); 211 { 212 int i; 213 214 for (i = 1 ; i <= DMA_RESERVE ; i++) 215 segtable[-i] = ((segtable[-i] & __HVM_PTE_PGMASK_4MB) 216 | __HVM_PTE_R | __HVM_PTE_W | __HVM_PTE_X 217 | __HEXAGON_C_UNC << 6 218 | __HVM_PDE_S_4MB); 219 } 220 221 printk(KERN_INFO "clearing segtable from %p to %p\n", segtable, 222 segtable_end); 223 while (segtable < (segtable_end-8)) 224 *(segtable++) = __HVM_PDE_S_INVALID; 225 /* stop the pointer at the device I/O 4MB page */ 226 227 printk(KERN_INFO "segtable = %p (should be equal to _K_io_map)\n", 228 segtable); 229 230 #if 0 231 /* Other half of the early device table from vm_init_segtable. */ 232 printk(KERN_INFO "&_K_init_devicetable = 0x%08x\n", 233 (unsigned long) _K_init_devicetable-PAGE_OFFSET); 234 *segtable = ((u32) (unsigned long) _K_init_devicetable-PAGE_OFFSET) | 235 __HVM_PDE_S_4KB; 236 printk(KERN_INFO "*segtable = 0x%08x\n", *segtable); 237 #endif 238 239 /* 240 * The bootmem allocator seemingly just lives to feed memory 241 * to the paging system 242 */ 243 printk(KERN_INFO "PAGE_SIZE=%lu\n", PAGE_SIZE); 244 paging_init(); /* See Gorman Book, 2.3 */ 245 246 /* 247 * At this point, the page allocator is kind of initialized, but 248 * apparently no pages are available (just like with the bootmem 249 * allocator), and need to be freed themselves via mem_init(), 250 * which is called by start_kernel() later on in the process 251 */ 252 } 253