1 // SPDX-License-Identifier: GPL-2.0
3 * linux/arch/m68k/mm/motorola.c
5 * Routines specific to the Motorola MMU, originally from:
6 * linux/arch/m68k/init.c
7 * which are Copyright (C) 1995 Hamish Macdonald
9 * Moved 8/20/1999 Sam Creasey
12 #include <linux/module.h>
13 #include <linux/signal.h>
14 #include <linux/sched.h>
16 #include <linux/swap.h>
17 #include <linux/kernel.h>
18 #include <linux/string.h>
19 #include <linux/types.h>
20 #include <linux/init.h>
21 #include <linux/memblock.h>
22 #include <linux/gfp.h>
24 #include <asm/setup.h>
25 #include <linux/uaccess.h>
27 #include <asm/pgalloc.h>
28 #include <asm/machdep.h>
32 #include <asm/atari_stram.h>
34 #include <asm/sections.h>
40 * Bits to add to page descriptors for "normal" caching mode.
41 * For 68020/030 this is 0.
42 * For 68040, this is _PAGE_CACHE040 (cachable, copyback)
44 unsigned long mm_cachebits;
45 EXPORT_SYMBOL(mm_cachebits);
48 /* size of memory already mapped in head.S */
49 extern __initdata unsigned long m68k_init_mapped_size;
51 extern unsigned long availmem;
53 static pte_t * __init kernel_page_table(void)
57 ptablep = (pte_t *)memblock_alloc_low(PAGE_SIZE, PAGE_SIZE);
59 panic("%s: Failed to allocate %lu bytes align=%lx\n",
60 __func__, PAGE_SIZE, PAGE_SIZE);
63 __flush_page_to_ram(ptablep);
64 flush_tlb_kernel_page(ptablep);
65 nocache_page(ptablep);
70 static pmd_t *last_pgtable __initdata = NULL;
71 pmd_t *zero_pgtable __initdata = NULL;
73 static pmd_t * __init kernel_ptr_table(void)
76 unsigned long pmd, last;
79 /* Find the last ptr table that was used in head.S and
80 * reuse the remaining space in that page for further
83 last = (unsigned long)kernel_pg_dir;
84 for (i = 0; i < PTRS_PER_PGD; i++) {
85 if (!pgd_present(kernel_pg_dir[i]))
87 pmd = __pgd_page(kernel_pg_dir[i]);
92 last_pgtable = (pmd_t *)last;
94 printk("kernel_ptr_init: %p\n", last_pgtable);
98 last_pgtable += PTRS_PER_PMD;
99 if (((unsigned long)last_pgtable & ~PAGE_MASK) == 0) {
100 last_pgtable = (pmd_t *)memblock_alloc_low(PAGE_SIZE,
103 panic("%s: Failed to allocate %lu bytes align=%lx\n",
104 __func__, PAGE_SIZE, PAGE_SIZE);
106 clear_page(last_pgtable);
107 __flush_page_to_ram(last_pgtable);
108 flush_tlb_kernel_page(last_pgtable);
109 nocache_page(last_pgtable);
115 static void __init map_node(int node)
117 #define PTRTREESIZE (256*1024)
118 #define ROOTTREESIZE (32*1024*1024)
119 unsigned long physaddr, virtaddr, size;
124 size = m68k_memory[node].size;
125 physaddr = m68k_memory[node].addr;
126 virtaddr = (unsigned long)phys_to_virt(physaddr);
127 physaddr |= m68k_supervisor_cachemode |
128 _PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_DIRTY;
129 if (CPU_IS_040_OR_060)
130 physaddr |= _PAGE_GLOBAL040;
134 if (!(virtaddr & (PTRTREESIZE-1)))
135 printk ("\npa=%#lx va=%#lx ", physaddr & PAGE_MASK,
138 pgd_dir = pgd_offset_k(virtaddr);
139 if (virtaddr && CPU_IS_020_OR_030) {
140 if (!(virtaddr & (ROOTTREESIZE-1)) &&
141 size >= ROOTTREESIZE) {
143 printk ("[very early term]");
145 pgd_val(*pgd_dir) = physaddr;
146 size -= ROOTTREESIZE;
147 virtaddr += ROOTTREESIZE;
148 physaddr += ROOTTREESIZE;
152 if (!pgd_present(*pgd_dir)) {
153 pmd_dir = kernel_ptr_table();
155 printk ("[new pointer %p]", pmd_dir);
157 pgd_set(pgd_dir, pmd_dir);
159 pmd_dir = pmd_offset(pgd_dir, virtaddr);
161 if (CPU_IS_020_OR_030) {
164 printk ("[early term]");
166 pmd_dir->pmd[(virtaddr/PTRTREESIZE) & 15] = physaddr;
167 physaddr += PTRTREESIZE;
171 printk ("[zero map]");
173 zero_pgtable = kernel_ptr_table();
174 pte_dir = (pte_t *)zero_pgtable;
175 pmd_dir->pmd[0] = virt_to_phys(pte_dir) |
176 _PAGE_TABLE | _PAGE_ACCESSED;
177 pte_val(*pte_dir++) = 0;
178 physaddr += PAGE_SIZE;
179 for (i = 1; i < 64; physaddr += PAGE_SIZE, i++)
180 pte_val(*pte_dir++) = physaddr;
183 virtaddr += PTRTREESIZE;
185 if (!pmd_present(*pmd_dir)) {
187 printk ("[new table]");
189 pte_dir = kernel_page_table();
190 pmd_set(pmd_dir, pte_dir);
192 pte_dir = pte_offset_kernel(pmd_dir, virtaddr);
195 if (!pte_present(*pte_dir))
196 pte_val(*pte_dir) = physaddr;
198 pte_val(*pte_dir) = 0;
200 virtaddr += PAGE_SIZE;
201 physaddr += PAGE_SIZE;
211 * paging_init() continues the virtual memory environment setup which
212 * was begun by the code in arch/head.S.
214 void __init paging_init(void)
216 unsigned long zones_size[MAX_NR_ZONES] = { 0, };
217 unsigned long min_addr, max_addr;
222 printk ("start of paging_init (%p, %lx)\n", kernel_pg_dir, availmem);
225 /* Fix the cache mode in the page descriptors for the 680[46]0. */
226 if (CPU_IS_040_OR_060) {
229 mm_cachebits = _PAGE_CACHE040;
231 for (i = 0; i < 16; i++)
232 pgprot_val(protection_map[i]) |= _PAGE_CACHE040;
235 min_addr = m68k_memory[0].addr;
236 max_addr = min_addr + m68k_memory[0].size;
237 memblock_add(m68k_memory[0].addr, m68k_memory[0].size);
238 for (i = 1; i < m68k_num_memory;) {
239 if (m68k_memory[i].addr < min_addr) {
240 printk("Ignoring memory chunk at 0x%lx:0x%lx before the first chunk\n",
241 m68k_memory[i].addr, m68k_memory[i].size);
242 printk("Fix your bootloader or use a memfile to make use of this area!\n");
244 memmove(m68k_memory + i, m68k_memory + i + 1,
245 (m68k_num_memory - i) * sizeof(struct m68k_mem_info));
248 memblock_add(m68k_memory[i].addr, m68k_memory[i].size);
249 addr = m68k_memory[i].addr + m68k_memory[i].size;
254 m68k_memoffset = min_addr - PAGE_OFFSET;
255 m68k_virt_to_node_shift = fls(max_addr - min_addr - 1) - 6;
257 module_fixup(NULL, __start_fixup, __stop_fixup);
260 high_memory = phys_to_virt(max_addr);
262 min_low_pfn = availmem >> PAGE_SHIFT;
263 max_pfn = max_low_pfn = max_addr >> PAGE_SHIFT;
265 /* Reserve kernel text/data/bss and the memory allocated in head.S */
266 memblock_reserve(m68k_memory[0].addr, availmem - m68k_memory[0].addr);
269 * Map the physical memory available into the kernel virtual
270 * address space. Make sure memblock will not try to allocate
271 * pages beyond the memory we already mapped in head.S
273 memblock_set_bottom_up(true);
275 for (i = 0; i < m68k_num_memory; i++) {
283 * initialize the bad page table and bad page to point
284 * to a couple of allocated pages
286 empty_zero_page = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
287 if (!empty_zero_page)
288 panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
289 __func__, PAGE_SIZE, PAGE_SIZE);
292 * Set up SFC/DFC registers
297 printk ("before free_area_init\n");
299 for (i = 0; i < m68k_num_memory; i++) {
300 zones_size[ZONE_DMA] = m68k_memory[i].size >> PAGE_SHIFT;
301 free_area_init_node(i, zones_size,
302 m68k_memory[i].addr >> PAGE_SHIFT, NULL);
303 if (node_present_pages(i))
304 node_set_state(i, N_NORMAL_MEMORY);