motorola.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * linux/arch/m68k/mm/motorola.c
  4 *
  5 * Routines specific to the Motorola MMU, originally from:
  6 * linux/arch/m68k/init.c
  7 * which are Copyright (C) 1995 Hamish Macdonald
  8 *
  9 * Moved 8/20/1999 Sam Creasey
 10 */
 11
 12#include <linux/module.h>
 13#include <linux/signal.h>
 14#include <linux/sched.h>
 15#include <linux/mm.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>
 23
 24#include <asm/setup.h>
 25#include <linux/uaccess.h>
 26#include <asm/page.h>
 27#include <asm/pgalloc.h>
 28#include <asm/machdep.h>
 29#include <asm/io.h>
 30#ifdef CONFIG_ATARI
 31#include <asm/atari_stram.h>
 32#endif
 33#include <asm/sections.h>
 34
 35#undef DEBUG
 36
 37#ifndef mm_cachebits
 38/*
 39 * Bits to add to page descriptors for "normal" caching mode.
 40 * For 68020/030 this is 0.
 41 * For 68040, this is _PAGE_CACHE040 (cachable, copyback)
 42 */
 43unsigned long mm_cachebits;
 44EXPORT_SYMBOL(mm_cachebits);
 45#endif
 46
 47/* Prior to calling these routines, the page should have been flushed
 48 * from both the cache and ATC, or the CPU might not notice that the
 49 * cache setting for the page has been changed. -jskov
 50 */
 51static inline void nocache_page(void *vaddr)
 52{
 53	unsigned long addr = (unsigned long)vaddr;
 54
 55	if (CPU_IS_040_OR_060) {
 56		pte_t *ptep = virt_to_kpte(addr);
 57
 58		*ptep = pte_mknocache(*ptep);
 59	}
 60}
 61
 62static inline void cache_page(void *vaddr)
 63{
 64	unsigned long addr = (unsigned long)vaddr;
 65
 66	if (CPU_IS_040_OR_060) {
 67		pte_t *ptep = virt_to_kpte(addr);
 68
 69		*ptep = pte_mkcache(*ptep);
 70	}
 71}
 72
 73/*
 74 * Motorola 680x0 user's manual recommends using uncached memory for address
 75 * translation tables.
 76 *
 77 * Seeing how the MMU can be external on (some of) these chips, that seems like
 78 * a very important recommendation to follow. Provide some helpers to combat
 79 * 'variation' amongst the users of this.
 80 */
 81
 82void mmu_page_ctor(void *page)
 83{
 84	__flush_pages_to_ram(page, 1);
 85	flush_tlb_kernel_page(page);
 86	nocache_page(page);
 87}
 88
 89void mmu_page_dtor(void *page)
 90{
 91	cache_page(page);
 92}
 93
 94/* ++andreas: {get,free}_pointer_table rewritten to use unused fields from
 95   struct ptdesc instead of separately kmalloced struct.  Stolen from
 96   arch/sparc/mm/srmmu.c ... */
 97
 98typedef struct list_head ptable_desc;
 99
100static struct list_head ptable_list[3] = {
101	LIST_HEAD_INIT(ptable_list[0]),
102	LIST_HEAD_INIT(ptable_list[1]),
103	LIST_HEAD_INIT(ptable_list[2]),
104};
105
106#define PD_PTABLE(ptdesc) ((ptable_desc *)&(virt_to_ptdesc((void *)(ptdesc))->pt_list))
107#define PD_PTDESC(ptable) (list_entry(ptable, struct ptdesc, pt_list))
108#define PD_MARKBITS(dp) (*(unsigned int *)&PD_PTDESC(dp)->pt_index)
109
110static const int ptable_shift[3] = {
111	7+2, /* PGD */
112	7+2, /* PMD */
113	6+2, /* PTE */
114};
115
116#define ptable_size(type) (1U << ptable_shift[type])
117#define ptable_mask(type) ((1U << (PAGE_SIZE / ptable_size(type))) - 1)
118
119void __init init_pointer_table(void *table, int type)
120{
121	ptable_desc *dp;
122	unsigned long ptable = (unsigned long)table;
123	unsigned long pt_addr = ptable & PAGE_MASK;
124	unsigned int mask = 1U << ((ptable - pt_addr)/ptable_size(type));
125
126	dp = PD_PTABLE(pt_addr);
127	if (!(PD_MARKBITS(dp) & mask)) {
128		PD_MARKBITS(dp) = ptable_mask(type);
129		list_add(dp, &ptable_list[type]);
130	}
131
132	PD_MARKBITS(dp) &= ~mask;
133	pr_debug("init_pointer_table: %lx, %x\n", ptable, PD_MARKBITS(dp));
134
135	/* unreserve the ptdesc so it's possible to free that ptdesc */
136	__ClearPageReserved(ptdesc_page(PD_PTDESC(dp)));
137	init_page_count(ptdesc_page(PD_PTDESC(dp)));
138
139	return;
140}
141
142void *get_pointer_table(struct mm_struct *mm, int type)
143{
144	ptable_desc *dp = ptable_list[type].next;
145	unsigned int mask = list_empty(&ptable_list[type]) ? 0 : PD_MARKBITS(dp);
146	unsigned int tmp, off;
147
148	/*
149	 * For a pointer table for a user process address space, a
150	 * table is taken from a ptdesc allocated for the purpose.  Each
151	 * ptdesc can hold 8 pointer tables.  The ptdesc is remapped in
152	 * virtual address space to be noncacheable.
153	 */
154	if (mask == 0) {
155		struct ptdesc *ptdesc;
156		ptable_desc *new;
157		void *pt_addr;
158
159		ptdesc = pagetable_alloc(GFP_KERNEL | __GFP_ZERO, 0);
160		if (!ptdesc)
161			return NULL;
162
163		pt_addr = ptdesc_address(ptdesc);
164
165		switch (type) {
166		case TABLE_PTE:
167			/*
168			 * m68k doesn't have SPLIT_PTE_PTLOCKS for not having
169			 * SMP.
170			 */
171			pagetable_pte_ctor(mm, ptdesc);
172			break;
173		case TABLE_PMD:
174			pagetable_pmd_ctor(mm, ptdesc);
175			break;
176		case TABLE_PGD:
177			pagetable_pgd_ctor(ptdesc);
178			break;
179		}
180
181		mmu_page_ctor(pt_addr);
182
183		new = PD_PTABLE(pt_addr);
184		PD_MARKBITS(new) = ptable_mask(type) - 1;
185		list_add_tail(new, dp);
186
187		return (pmd_t *)pt_addr;
188	}
189
190	for (tmp = 1, off = 0; (mask & tmp) == 0; tmp <<= 1, off += ptable_size(type))
191		;
192	PD_MARKBITS(dp) = mask & ~tmp;
193	if (!PD_MARKBITS(dp)) {
194		/* move to end of list */
195		list_move_tail(dp, &ptable_list[type]);
196	}
197	return ptdesc_address(PD_PTDESC(dp)) + off;
198}
199
200int free_pointer_table(void *table, int type)
201{
202	ptable_desc *dp;
203	unsigned long ptable = (unsigned long)table;
204	unsigned long pt_addr = ptable & PAGE_MASK;
205	unsigned int mask = 1U << ((ptable - pt_addr)/ptable_size(type));
206
207	dp = PD_PTABLE(pt_addr);
208	if (PD_MARKBITS (dp) & mask)
209		panic ("table already free!");
210
211	PD_MARKBITS (dp) |= mask;
212
213	if (PD_MARKBITS(dp) == ptable_mask(type)) {
214		/* all tables in ptdesc are free, free ptdesc */
215		list_del(dp);
216		mmu_page_dtor((void *)pt_addr);
217		pagetable_dtor_free(virt_to_ptdesc((void *)pt_addr));
218		return 1;
219	} else if (ptable_list[type].next != dp) {
220		/*
221		 * move this descriptor to the front of the list, since
222		 * it has one or more free tables.
223		 */
224		list_move(dp, &ptable_list[type]);
225	}
226	return 0;
227}
228
229/* size of memory already mapped in head.S */
230extern __initdata unsigned long m68k_init_mapped_size;
231
232extern unsigned long availmem;
233
234static pte_t *last_pte_table __initdata = NULL;
235
236static pte_t * __init kernel_page_table(void)
237{
238	pte_t *pte_table = last_pte_table;
239
240	if (PAGE_ALIGNED(last_pte_table)) {
241		pte_table = memblock_alloc_low(PAGE_SIZE, PAGE_SIZE);
242		if (!pte_table) {
243			panic("%s: Failed to allocate %lu bytes align=%lx\n",
244					__func__, PAGE_SIZE, PAGE_SIZE);
245		}
246
247		clear_page(pte_table);
248		mmu_page_ctor(pte_table);
249
250		last_pte_table = pte_table;
251	}
252
253	last_pte_table += PTRS_PER_PTE;
254
255	return pte_table;
256}
257
258static pmd_t *last_pmd_table __initdata = NULL;
259
260static pmd_t * __init kernel_ptr_table(void)
261{
262	if (!last_pmd_table) {
263		unsigned long pmd, last;
264		int i;
265
266		/* Find the last ptr table that was used in head.S and
267		 * reuse the remaining space in that page for further
268		 * ptr tables.
269		 */
270		last = (unsigned long)kernel_pg_dir;
271		for (i = 0; i < PTRS_PER_PGD; i++) {
272			pud_t *pud = (pud_t *)(&kernel_pg_dir[i]);
273
274			if (!pud_present(*pud))
275				continue;
276			pmd = pgd_page_vaddr(kernel_pg_dir[i]);
277			if (pmd > last)
278				last = pmd;
279		}
280
281		last_pmd_table = (pmd_t *)last;
282#ifdef DEBUG
283		printk("kernel_ptr_init: %p\n", last_pmd_table);
284#endif
285	}
286
287	last_pmd_table += PTRS_PER_PMD;
288	if (PAGE_ALIGNED(last_pmd_table)) {
289		last_pmd_table = memblock_alloc_low(PAGE_SIZE, PAGE_SIZE);
290		if (!last_pmd_table)
291			panic("%s: Failed to allocate %lu bytes align=%lx\n",
292			      __func__, PAGE_SIZE, PAGE_SIZE);
293
294		clear_page(last_pmd_table);
295		mmu_page_ctor(last_pmd_table);
296	}
297
298	return last_pmd_table;
299}
300
301static void __init map_node(int node)
302{
303	unsigned long physaddr, virtaddr, size;
304	pgd_t *pgd_dir;
305	p4d_t *p4d_dir;
306	pud_t *pud_dir;
307	pmd_t *pmd_dir;
308	pte_t *pte_dir;
309
310	size = m68k_memory[node].size;
311	physaddr = m68k_memory[node].addr;
312	virtaddr = (unsigned long)phys_to_virt(physaddr);
313	physaddr |= m68k_supervisor_cachemode |
314		    _PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_DIRTY;
315	if (CPU_IS_040_OR_060)
316		physaddr |= _PAGE_GLOBAL040;
317
318	while (size > 0) {
319#ifdef DEBUG
320		if (!(virtaddr & (PMD_SIZE-1)))
321			printk ("\npa=%#lx va=%#lx ", physaddr & PAGE_MASK,
322				virtaddr);
323#endif
324		pgd_dir = pgd_offset_k(virtaddr);
325		if (virtaddr && CPU_IS_020_OR_030) {
326			if (!(virtaddr & (PGDIR_SIZE-1)) &&
327			    size >= PGDIR_SIZE) {
328#ifdef DEBUG
329				printk ("[very early term]");
330#endif
331				pgd_val(*pgd_dir) = physaddr;
332				size -= PGDIR_SIZE;
333				virtaddr += PGDIR_SIZE;
334				physaddr += PGDIR_SIZE;
335				continue;
336			}
337		}
338		p4d_dir = p4d_offset(pgd_dir, virtaddr);
339		pud_dir = pud_offset(p4d_dir, virtaddr);
340		if (!pud_present(*pud_dir)) {
341			pmd_dir = kernel_ptr_table();
342#ifdef DEBUG
343			printk ("[new pointer %p]", pmd_dir);
344#endif
345			pud_set(pud_dir, pmd_dir);
346		} else
347			pmd_dir = pmd_offset(pud_dir, virtaddr);
348
349		if (CPU_IS_020_OR_030) {
350			if (virtaddr) {
351#ifdef DEBUG
352				printk ("[early term]");
353#endif
354				pmd_val(*pmd_dir) = physaddr;
355				physaddr += PMD_SIZE;
356			} else {
357				int i;
358#ifdef DEBUG
359				printk ("[zero map]");
360#endif
361				pte_dir = kernel_page_table();
362				pmd_set(pmd_dir, pte_dir);
363
364				pte_val(*pte_dir++) = 0;
365				physaddr += PAGE_SIZE;
366				for (i = 1; i < PTRS_PER_PTE; physaddr += PAGE_SIZE, i++)
367					pte_val(*pte_dir++) = physaddr;
368			}
369			size -= PMD_SIZE;
370			virtaddr += PMD_SIZE;
371		} else {
372			if (!pmd_present(*pmd_dir)) {
373#ifdef DEBUG
374				printk ("[new table]");
375#endif
376				pte_dir = kernel_page_table();
377				pmd_set(pmd_dir, pte_dir);
378			}
379			pte_dir = pte_offset_kernel(pmd_dir, virtaddr);
380
381			if (virtaddr) {
382				if (!pte_present(*pte_dir))
383					pte_val(*pte_dir) = physaddr;
384			} else
385				pte_val(*pte_dir) = 0;
386			size -= PAGE_SIZE;
387			virtaddr += PAGE_SIZE;
388			physaddr += PAGE_SIZE;
389		}
390
391	}
392#ifdef DEBUG
393	printk("\n");
394#endif
395}
396
397/*
398 * Alternate definitions that are compile time constants, for
399 * initializing protection_map.  The cachebits are fixed later.
400 */
401#define PAGE_NONE_C	__pgprot(_PAGE_PROTNONE | _PAGE_ACCESSED)
402#define PAGE_SHARED_C	__pgprot(_PAGE_PRESENT | _PAGE_ACCESSED)
403#define PAGE_COPY_C	__pgprot(_PAGE_PRESENT | _PAGE_RONLY | _PAGE_ACCESSED)
404#define PAGE_READONLY_C	__pgprot(_PAGE_PRESENT | _PAGE_RONLY | _PAGE_ACCESSED)
405
406static pgprot_t protection_map[16] __ro_after_init = {
407	[VM_NONE]					= PAGE_NONE_C,
408	[VM_READ]					= PAGE_READONLY_C,
409	[VM_WRITE]					= PAGE_COPY_C,
410	[VM_WRITE | VM_READ]				= PAGE_COPY_C,
411	[VM_EXEC]					= PAGE_READONLY_C,
412	[VM_EXEC | VM_READ]				= PAGE_READONLY_C,
413	[VM_EXEC | VM_WRITE]				= PAGE_COPY_C,
414	[VM_EXEC | VM_WRITE | VM_READ]			= PAGE_COPY_C,
415	[VM_SHARED]					= PAGE_NONE_C,
416	[VM_SHARED | VM_READ]				= PAGE_READONLY_C,
417	[VM_SHARED | VM_WRITE]				= PAGE_SHARED_C,
418	[VM_SHARED | VM_WRITE | VM_READ]		= PAGE_SHARED_C,
419	[VM_SHARED | VM_EXEC]				= PAGE_READONLY_C,
420	[VM_SHARED | VM_EXEC | VM_READ]			= PAGE_READONLY_C,
421	[VM_SHARED | VM_EXEC | VM_WRITE]		= PAGE_SHARED_C,
422	[VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]	= PAGE_SHARED_C
423};
424DECLARE_VM_GET_PAGE_PROT
425
426/*
427 * paging_init() continues the virtual memory environment setup which
428 * was begun by the code in arch/head.S.
429 */
430void __init paging_init(void)
431{
432	unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0, };
433	unsigned long min_addr, max_addr;
434	unsigned long addr;
435	int i;
436
437#ifdef DEBUG
438	printk ("start of paging_init (%p, %lx)\n", kernel_pg_dir, availmem);
439#endif
440
441	/* Fix the cache mode in the page descriptors for the 680[46]0.  */
442	if (CPU_IS_040_OR_060) {
443		int i;
444#ifndef mm_cachebits
445		mm_cachebits = _PAGE_CACHE040;
446#endif
447		for (i = 0; i < 16; i++)
448			pgprot_val(protection_map[i]) |= _PAGE_CACHE040;
449	}
450
451	min_addr = m68k_memory[0].addr;
452	max_addr = min_addr + m68k_memory[0].size - 1;
453	memblock_add_node(m68k_memory[0].addr, m68k_memory[0].size, 0,
454			  MEMBLOCK_NONE);
455	for (i = 1; i < m68k_num_memory;) {
456		if (m68k_memory[i].addr < min_addr) {
457			printk("Ignoring memory chunk at 0x%lx:0x%lx before the first chunk\n",
458				m68k_memory[i].addr, m68k_memory[i].size);
459			printk("Fix your bootloader or use a memfile to make use of this area!\n");
460			m68k_num_memory--;
461			memmove(m68k_memory + i, m68k_memory + i + 1,
462				(m68k_num_memory - i) * sizeof(struct m68k_mem_info));
463			continue;
464		}
465		memblock_add_node(m68k_memory[i].addr, m68k_memory[i].size, i,
466				  MEMBLOCK_NONE);
467		addr = m68k_memory[i].addr + m68k_memory[i].size - 1;
468		if (addr > max_addr)
469			max_addr = addr;
470		i++;
471	}
472	m68k_memoffset = min_addr - PAGE_OFFSET;
473	m68k_virt_to_node_shift = fls(max_addr - min_addr) - 6;
474
475	module_fixup(NULL, __start_fixup, __stop_fixup);
476	flush_icache();
477
478	high_memory = phys_to_virt(max_addr) + 1;
479
480	min_low_pfn = availmem >> PAGE_SHIFT;
481	max_pfn = max_low_pfn = (max_addr >> PAGE_SHIFT) + 1;
482
483	/* Reserve kernel text/data/bss and the memory allocated in head.S */
484	memblock_reserve(m68k_memory[0].addr, availmem - m68k_memory[0].addr);
485
486	/*
487	 * Map the physical memory available into the kernel virtual
488	 * address space. Make sure memblock will not try to allocate
489	 * pages beyond the memory we already mapped in head.S
490	 */
491	memblock_set_bottom_up(true);
492
493	for (i = 0; i < m68k_num_memory; i++) {
494		m68k_setup_node(i);
495		map_node(i);
496	}
497
498	flush_tlb_all();
499
500	early_memtest(min_addr, max_addr);
501
502	/*
503	 * initialize the bad page table and bad page to point
504	 * to a couple of allocated pages
505	 */
506	empty_zero_page = memblock_alloc_or_panic(PAGE_SIZE, PAGE_SIZE);
507
508	/*
509	 * Set up SFC/DFC registers
510	 */
511	set_fc(USER_DATA);
512
513#ifdef DEBUG
514	printk ("before free_area_init\n");
515#endif
516	for (i = 0; i < m68k_num_memory; i++)
517		if (node_present_pages(i))
518			node_set_state(i, N_NORMAL_MEMORY);
519
520	max_zone_pfn[ZONE_DMA] = memblock_end_of_DRAM();
521	free_area_init(max_zone_pfn);
522}