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 59 /* 60 * To-Do: someone somewhere should wipe out the bootmem map 61 * after we're done? 62 */ 63 64 /* 65 * This can be moved to some more virtual-memory-specific 66 * initialization hook at some point. Set the init_mm 67 * descriptors "context" value to point to the initial 68 * kernel segment table's physical address. 69 */ 70 init_mm.context.ptbase = __pa(init_mm.pgd); 71 } 72 73 void sync_icache_dcache(pte_t pte) 74 { 75 unsigned long addr; 76 struct page *page; 77 78 page = pte_page(pte); 79 addr = (unsigned long) page_address(page); 80 81 __vmcache_idsync(addr, PAGE_SIZE); 82 } 83 84 /* 85 * In order to set up page allocator "nodes", 86 * somebody has to call free_area_init() for UMA. 87 * 88 * In this mode, we only have one pg_data_t 89 * structure: contig_mem_data. 90 */ 91 void __init paging_init(void) 92 { 93 unsigned long max_zone_pfn[MAX_NR_ZONES] = {0, }; 94 95 /* 96 * This is not particularly well documented anywhere, but 97 * give ZONE_NORMAL all the memory, including the big holes 98 * left by the kernel+bootmem_map which are already left as reserved 99 * in the bootmem_map; free_area_init should see those bits and 100 * adjust accordingly. 101 */ 102 103 max_zone_pfn[ZONE_NORMAL] = max_low_pfn; 104 105 free_area_init(max_zone_pfn); /* sets up the zonelists and mem_map */ 106 107 /* 108 * Start of high memory area. Will probably need something more 109 * fancy if we... get more fancy. 110 */ 111 high_memory = (void *)((bootmem_lastpg + 1) << PAGE_SHIFT); 112 } 113 114 #ifndef DMA_RESERVE 115 #define DMA_RESERVE (4) 116 #endif 117 118 #define DMA_CHUNKSIZE (1<<22) 119 #define DMA_RESERVED_BYTES (DMA_RESERVE * DMA_CHUNKSIZE) 120 121 /* 122 * Pick out the memory size. We look for mem=size, 123 * where size is "size[KkMm]" 124 */ 125 static int __init early_mem(char *p) 126 { 127 unsigned long size; 128 char *endp; 129 130 size = memparse(p, &endp); 131 132 bootmem_lastpg = PFN_DOWN(size); 133 134 return 0; 135 } 136 early_param("mem", early_mem); 137 138 size_t hexagon_coherent_pool_size = (size_t) (DMA_RESERVE << 22); 139 140 void __init setup_arch_memory(void) 141 { 142 /* XXX Todo: this probably should be cleaned up */ 143 u32 *segtable = (u32 *) &swapper_pg_dir[0]; 144 u32 *segtable_end; 145 146 /* 147 * Set up boot memory allocator 148 * 149 * The Gorman book also talks about these functions. 150 * This needs to change for highmem setups. 151 */ 152 153 /* Prior to this, bootmem_lastpg is actually mem size */ 154 bootmem_lastpg += ARCH_PFN_OFFSET; 155 156 /* Memory size needs to be a multiple of 16M */ 157 bootmem_lastpg = PFN_DOWN((bootmem_lastpg << PAGE_SHIFT) & 158 ~((BIG_KERNEL_PAGE_SIZE) - 1)); 159 160 memblock_add(PHYS_OFFSET, 161 (bootmem_lastpg - ARCH_PFN_OFFSET) << PAGE_SHIFT); 162 163 /* Reserve kernel text/data/bss */ 164 memblock_reserve(PHYS_OFFSET, 165 (bootmem_startpg - ARCH_PFN_OFFSET) << PAGE_SHIFT); 166 /* 167 * Reserve the top DMA_RESERVE bytes of RAM for DMA (uncached) 168 * memory allocation 169 */ 170 max_low_pfn = bootmem_lastpg - PFN_DOWN(DMA_RESERVED_BYTES); 171 min_low_pfn = ARCH_PFN_OFFSET; 172 memblock_reserve(PFN_PHYS(max_low_pfn), DMA_RESERVED_BYTES); 173 174 printk(KERN_INFO "bootmem_startpg: 0x%08lx\n", bootmem_startpg); 175 printk(KERN_INFO "bootmem_lastpg: 0x%08lx\n", bootmem_lastpg); 176 printk(KERN_INFO "min_low_pfn: 0x%08lx\n", min_low_pfn); 177 printk(KERN_INFO "max_low_pfn: 0x%08lx\n", max_low_pfn); 178 179 /* 180 * The default VM page tables (will be) populated with 181 * VA=PA+PAGE_OFFSET mapping. We go in and invalidate entries 182 * higher than what we have memory for. 183 */ 184 185 /* this is pointer arithmetic; each entry covers 4MB */ 186 segtable = segtable + (PAGE_OFFSET >> 22); 187 188 /* this actually only goes to the end of the first gig */ 189 segtable_end = segtable + (1<<(30-22)); 190 191 /* 192 * Move forward to the start of empty pages; take into account 193 * phys_offset shift. 194 */ 195 196 segtable += (bootmem_lastpg-ARCH_PFN_OFFSET)>>(22-PAGE_SHIFT); 197 { 198 int i; 199 200 for (i = 1 ; i <= DMA_RESERVE ; i++) 201 segtable[-i] = ((segtable[-i] & __HVM_PTE_PGMASK_4MB) 202 | __HVM_PTE_R | __HVM_PTE_W | __HVM_PTE_X 203 | __HEXAGON_C_UNC << 6 204 | __HVM_PDE_S_4MB); 205 } 206 207 printk(KERN_INFO "clearing segtable from %p to %p\n", segtable, 208 segtable_end); 209 while (segtable < (segtable_end-8)) 210 *(segtable++) = __HVM_PDE_S_INVALID; 211 /* stop the pointer at the device I/O 4MB page */ 212 213 printk(KERN_INFO "segtable = %p (should be equal to _K_io_map)\n", 214 segtable); 215 216 #if 0 217 /* Other half of the early device table from vm_init_segtable. */ 218 printk(KERN_INFO "&_K_init_devicetable = 0x%08x\n", 219 (unsigned long) _K_init_devicetable-PAGE_OFFSET); 220 *segtable = ((u32) (unsigned long) _K_init_devicetable-PAGE_OFFSET) | 221 __HVM_PDE_S_4KB; 222 printk(KERN_INFO "*segtable = 0x%08x\n", *segtable); 223 #endif 224 225 /* 226 * The bootmem allocator seemingly just lives to feed memory 227 * to the paging system 228 */ 229 printk(KERN_INFO "PAGE_SIZE=%lu\n", PAGE_SIZE); 230 paging_init(); /* See Gorman Book, 2.3 */ 231 232 /* 233 * At this point, the page allocator is kind of initialized, but 234 * apparently no pages are available (just like with the bootmem 235 * allocator), and need to be freed themselves via mem_init(), 236 * which is called by start_kernel() later on in the process 237 */ 238 } 239