1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * OpenRISC idle.c 4 * 5 * Linux architectural port borrowing liberally from similar works of 6 * others. All original copyrights apply as per the original source 7 * declaration. 8 * 9 * Modifications for the OpenRISC architecture: 10 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com> 11 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se> 12 */ 13 14 #include <linux/signal.h> 15 #include <linux/sched.h> 16 #include <linux/kernel.h> 17 #include <linux/errno.h> 18 #include <linux/string.h> 19 #include <linux/types.h> 20 #include <linux/ptrace.h> 21 #include <linux/mman.h> 22 #include <linux/mm.h> 23 #include <linux/swap.h> 24 #include <linux/smp.h> 25 #include <linux/memblock.h> 26 #include <linux/init.h> 27 #include <linux/delay.h> 28 #include <linux/blkdev.h> /* for initrd_* */ 29 #include <linux/pagemap.h> 30 31 #include <asm/pgalloc.h> 32 #include <asm/dma.h> 33 #include <asm/io.h> 34 #include <asm/tlb.h> 35 #include <asm/mmu_context.h> 36 #include <asm/fixmap.h> 37 #include <asm/tlbflush.h> 38 #include <asm/sections.h> 39 40 int mem_init_done; 41 42 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers); 43 44 static void __init zone_sizes_init(void) 45 { 46 unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 }; 47 48 /* 49 * We use only ZONE_NORMAL 50 */ 51 max_zone_pfn[ZONE_NORMAL] = max_low_pfn; 52 53 free_area_init(max_zone_pfn); 54 } 55 56 extern const char _s_kernel_ro[], _e_kernel_ro[]; 57 58 /* 59 * Map all physical memory into kernel's address space. 60 * 61 * This is explicitly coded for two-level page tables, so if you need 62 * something else then this needs to change. 63 */ 64 static void __init map_ram(void) 65 { 66 phys_addr_t start, end; 67 unsigned long v, p, e; 68 pgprot_t prot; 69 pgd_t *pge; 70 p4d_t *p4e; 71 pud_t *pue; 72 pmd_t *pme; 73 pte_t *pte; 74 u64 i; 75 /* These mark extents of read-only kernel pages... 76 * ...from vmlinux.lds.S 77 */ 78 struct memblock_region *region; 79 80 v = PAGE_OFFSET; 81 82 for_each_mem_range(i, &start, &end) { 83 p = (u32) start & PAGE_MASK; 84 e = (u32) end; 85 86 v = (u32) __va(p); 87 pge = pgd_offset_k(v); 88 89 while (p < e) { 90 int j; 91 p4e = p4d_offset(pge, v); 92 pue = pud_offset(p4e, v); 93 pme = pmd_offset(pue, v); 94 95 if ((u32) pue != (u32) pge || (u32) pme != (u32) pge) { 96 panic("%s: OR1K kernel hardcoded for " 97 "two-level page tables", 98 __func__); 99 } 100 101 /* Alloc one page for holding PTE's... */ 102 pte = memblock_alloc_raw(PAGE_SIZE, PAGE_SIZE); 103 if (!pte) 104 panic("%s: Failed to allocate page for PTEs\n", 105 __func__); 106 set_pmd(pme, __pmd(_KERNPG_TABLE + __pa(pte))); 107 108 /* Fill the newly allocated page with PTE'S */ 109 for (j = 0; p < e && j < PTRS_PER_PTE; 110 v += PAGE_SIZE, p += PAGE_SIZE, j++, pte++) { 111 if (v >= (u32) _e_kernel_ro || 112 v < (u32) _s_kernel_ro) 113 prot = PAGE_KERNEL; 114 else 115 prot = PAGE_KERNEL_RO; 116 117 set_pte(pte, mk_pte_phys(p, prot)); 118 } 119 120 pge++; 121 } 122 123 printk(KERN_INFO "%s: Memory: 0x%x-0x%x\n", __func__, 124 region->base, region->base + region->size); 125 } 126 } 127 128 void __init paging_init(void) 129 { 130 extern void tlb_init(void); 131 132 unsigned long end; 133 int i; 134 135 printk(KERN_INFO "Setting up paging and PTEs.\n"); 136 137 /* clear out the init_mm.pgd that will contain the kernel's mappings */ 138 139 for (i = 0; i < PTRS_PER_PGD; i++) 140 swapper_pg_dir[i] = __pgd(0); 141 142 /* make sure the current pgd table points to something sane 143 * (even if it is most probably not used until the next 144 * switch_mm) 145 */ 146 current_pgd[smp_processor_id()] = init_mm.pgd; 147 148 end = (unsigned long)__va(max_low_pfn * PAGE_SIZE); 149 150 map_ram(); 151 152 zone_sizes_init(); 153 154 /* self modifying code ;) */ 155 /* Since the old TLB miss handler has been running up until now, 156 * the kernel pages are still all RW, so we can still modify the 157 * text directly... after this change and a TLB flush, the kernel 158 * pages will become RO. 159 */ 160 { 161 extern unsigned long dtlb_miss_handler; 162 extern unsigned long itlb_miss_handler; 163 164 unsigned long *dtlb_vector = __va(0x900); 165 unsigned long *itlb_vector = __va(0xa00); 166 167 printk(KERN_INFO "itlb_miss_handler %p\n", &itlb_miss_handler); 168 *itlb_vector = ((unsigned long)&itlb_miss_handler - 169 (unsigned long)itlb_vector) >> 2; 170 171 /* Soft ordering constraint to ensure that dtlb_vector is 172 * the last thing updated 173 */ 174 barrier(); 175 176 printk(KERN_INFO "dtlb_miss_handler %p\n", &dtlb_miss_handler); 177 *dtlb_vector = ((unsigned long)&dtlb_miss_handler - 178 (unsigned long)dtlb_vector) >> 2; 179 180 } 181 182 /* Soft ordering constraint to ensure that cache invalidation and 183 * TLB flush really happen _after_ code has been modified. 184 */ 185 barrier(); 186 187 /* Invalidate instruction caches after code modification */ 188 mtspr(SPR_ICBIR, 0x900); 189 mtspr(SPR_ICBIR, 0xa00); 190 191 /* New TLB miss handlers and kernel page tables are in now place. 192 * Make sure that page flags get updated for all pages in TLB by 193 * flushing the TLB and forcing all TLB entries to be recreated 194 * from their page table flags. 195 */ 196 flush_tlb_all(); 197 } 198 199 /* References to section boundaries */ 200 201 void __init mem_init(void) 202 { 203 BUG_ON(!mem_map); 204 205 max_mapnr = max_low_pfn; 206 high_memory = (void *)__va(max_low_pfn * PAGE_SIZE); 207 208 /* clear the zero-page */ 209 memset((void *)empty_zero_page, 0, PAGE_SIZE); 210 211 /* this will put all low memory onto the freelists */ 212 memblock_free_all(); 213 214 printk("mem_init_done ...........................................\n"); 215 mem_init_done = 1; 216 return; 217 } 218