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-rw-r--r--arch/m68k/mm/motorola.c513
1 files changed, 513 insertions, 0 deletions
diff --git a/arch/m68k/mm/motorola.c b/arch/m68k/mm/motorola.c
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+++ b/arch/m68k/mm/motorola.c
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+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/arch/m68k/mm/motorola.c
+ *
+ * Routines specific to the Motorola MMU, originally from:
+ * linux/arch/m68k/init.c
+ * which are Copyright (C) 1995 Hamish Macdonald
+ *
+ * Moved 8/20/1999 Sam Creasey
+ */
+
+#include <linux/module.h>
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/swap.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/init.h>
+#include <linux/memblock.h>
+#include <linux/gfp.h>
+
+#include <asm/setup.h>
+#include <linux/uaccess.h>
+#include <asm/page.h>
+#include <asm/pgalloc.h>
+#include <asm/machdep.h>
+#include <asm/io.h>
+#ifdef CONFIG_ATARI
+#include <asm/atari_stram.h>
+#endif
+#include <asm/sections.h>
+
+#undef DEBUG
+
+#ifndef mm_cachebits
+/*
+ * Bits to add to page descriptors for "normal" caching mode.
+ * For 68020/030 this is 0.
+ * For 68040, this is _PAGE_CACHE040 (cachable, copyback)
+ */
+unsigned long mm_cachebits;
+EXPORT_SYMBOL(mm_cachebits);
+#endif
+
+/* Prior to calling these routines, the page should have been flushed
+ * from both the cache and ATC, or the CPU might not notice that the
+ * cache setting for the page has been changed. -jskov
+ */
+static inline void nocache_page(void *vaddr)
+{
+ unsigned long addr = (unsigned long)vaddr;
+
+ if (CPU_IS_040_OR_060) {
+ pte_t *ptep = virt_to_kpte(addr);
+
+ *ptep = pte_mknocache(*ptep);
+ }
+}
+
+static inline void cache_page(void *vaddr)
+{
+ unsigned long addr = (unsigned long)vaddr;
+
+ if (CPU_IS_040_OR_060) {
+ pte_t *ptep = virt_to_kpte(addr);
+
+ *ptep = pte_mkcache(*ptep);
+ }
+}
+
+/*
+ * Motorola 680x0 user's manual recommends using uncached memory for address
+ * translation tables.
+ *
+ * Seeing how the MMU can be external on (some of) these chips, that seems like
+ * a very important recommendation to follow. Provide some helpers to combat
+ * 'variation' amongst the users of this.
+ */
+
+void mmu_page_ctor(void *page)
+{
+ __flush_page_to_ram(page);
+ flush_tlb_kernel_page(page);
+ nocache_page(page);
+}
+
+void mmu_page_dtor(void *page)
+{
+ cache_page(page);
+}
+
+/* ++andreas: {get,free}_pointer_table rewritten to use unused fields from
+ struct page instead of separately kmalloced struct. Stolen from
+ arch/sparc/mm/srmmu.c ... */
+
+typedef struct list_head ptable_desc;
+
+static struct list_head ptable_list[2] = {
+ LIST_HEAD_INIT(ptable_list[0]),
+ LIST_HEAD_INIT(ptable_list[1]),
+};
+
+#define PD_PTABLE(page) ((ptable_desc *)&(virt_to_page(page)->lru))
+#define PD_PAGE(ptable) (list_entry(ptable, struct page, lru))
+#define PD_MARKBITS(dp) (*(unsigned int *)&PD_PAGE(dp)->index)
+
+static const int ptable_shift[2] = {
+ 7+2, /* PGD, PMD */
+ 6+2, /* PTE */
+};
+
+#define ptable_size(type) (1U << ptable_shift[type])
+#define ptable_mask(type) ((1U << (PAGE_SIZE / ptable_size(type))) - 1)
+
+void __init init_pointer_table(void *table, int type)
+{
+ ptable_desc *dp;
+ unsigned long ptable = (unsigned long)table;
+ unsigned long page = ptable & PAGE_MASK;
+ unsigned int mask = 1U << ((ptable - page)/ptable_size(type));
+
+ dp = PD_PTABLE(page);
+ if (!(PD_MARKBITS(dp) & mask)) {
+ PD_MARKBITS(dp) = ptable_mask(type);
+ list_add(dp, &ptable_list[type]);
+ }
+
+ PD_MARKBITS(dp) &= ~mask;
+ pr_debug("init_pointer_table: %lx, %x\n", ptable, PD_MARKBITS(dp));
+
+ /* unreserve the page so it's possible to free that page */
+ __ClearPageReserved(PD_PAGE(dp));
+ init_page_count(PD_PAGE(dp));
+
+ return;
+}
+
+void *get_pointer_table(int type)
+{
+ ptable_desc *dp = ptable_list[type].next;
+ unsigned int mask = list_empty(&ptable_list[type]) ? 0 : PD_MARKBITS(dp);
+ unsigned int tmp, off;
+
+ /*
+ * For a pointer table for a user process address space, a
+ * table is taken from a page allocated for the purpose. Each
+ * page can hold 8 pointer tables. The page is remapped in
+ * virtual address space to be noncacheable.
+ */
+ if (mask == 0) {
+ void *page;
+ ptable_desc *new;
+
+ if (!(page = (void *)get_zeroed_page(GFP_KERNEL)))
+ return NULL;
+
+ if (type == TABLE_PTE) {
+ /*
+ * m68k doesn't have SPLIT_PTE_PTLOCKS for not having
+ * SMP.
+ */
+ pgtable_pte_page_ctor(virt_to_page(page));
+ }
+
+ mmu_page_ctor(page);
+
+ new = PD_PTABLE(page);
+ PD_MARKBITS(new) = ptable_mask(type) - 1;
+ list_add_tail(new, dp);
+
+ return (pmd_t *)page;
+ }
+
+ for (tmp = 1, off = 0; (mask & tmp) == 0; tmp <<= 1, off += ptable_size(type))
+ ;
+ PD_MARKBITS(dp) = mask & ~tmp;
+ if (!PD_MARKBITS(dp)) {
+ /* move to end of list */
+ list_move_tail(dp, &ptable_list[type]);
+ }
+ return page_address(PD_PAGE(dp)) + off;
+}
+
+int free_pointer_table(void *table, int type)
+{
+ ptable_desc *dp;
+ unsigned long ptable = (unsigned long)table;
+ unsigned long page = ptable & PAGE_MASK;
+ unsigned int mask = 1U << ((ptable - page)/ptable_size(type));
+
+ dp = PD_PTABLE(page);
+ if (PD_MARKBITS (dp) & mask)
+ panic ("table already free!");
+
+ PD_MARKBITS (dp) |= mask;
+
+ if (PD_MARKBITS(dp) == ptable_mask(type)) {
+ /* all tables in page are free, free page */
+ list_del(dp);
+ mmu_page_dtor((void *)page);
+ if (type == TABLE_PTE)
+ pgtable_pte_page_dtor(virt_to_page(page));
+ free_page (page);
+ return 1;
+ } else if (ptable_list[type].next != dp) {
+ /*
+ * move this descriptor to the front of the list, since
+ * it has one or more free tables.
+ */
+ list_move(dp, &ptable_list[type]);
+ }
+ return 0;
+}
+
+/* size of memory already mapped in head.S */
+extern __initdata unsigned long m68k_init_mapped_size;
+
+extern unsigned long availmem;
+
+static pte_t *last_pte_table __initdata = NULL;
+
+static pte_t * __init kernel_page_table(void)
+{
+ pte_t *pte_table = last_pte_table;
+
+ if (PAGE_ALIGNED(last_pte_table)) {
+ pte_table = memblock_alloc_low(PAGE_SIZE, PAGE_SIZE);
+ if (!pte_table) {
+ panic("%s: Failed to allocate %lu bytes align=%lx\n",
+ __func__, PAGE_SIZE, PAGE_SIZE);
+ }
+
+ clear_page(pte_table);
+ mmu_page_ctor(pte_table);
+
+ last_pte_table = pte_table;
+ }
+
+ last_pte_table += PTRS_PER_PTE;
+
+ return pte_table;
+}
+
+static pmd_t *last_pmd_table __initdata = NULL;
+
+static pmd_t * __init kernel_ptr_table(void)
+{
+ if (!last_pmd_table) {
+ unsigned long pmd, last;
+ int i;
+
+ /* Find the last ptr table that was used in head.S and
+ * reuse the remaining space in that page for further
+ * ptr tables.
+ */
+ last = (unsigned long)kernel_pg_dir;
+ for (i = 0; i < PTRS_PER_PGD; i++) {
+ pud_t *pud = (pud_t *)(&kernel_pg_dir[i]);
+
+ if (!pud_present(*pud))
+ continue;
+ pmd = pgd_page_vaddr(kernel_pg_dir[i]);
+ if (pmd > last)
+ last = pmd;
+ }
+
+ last_pmd_table = (pmd_t *)last;
+#ifdef DEBUG
+ printk("kernel_ptr_init: %p\n", last_pmd_table);
+#endif
+ }
+
+ last_pmd_table += PTRS_PER_PMD;
+ if (PAGE_ALIGNED(last_pmd_table)) {
+ last_pmd_table = memblock_alloc_low(PAGE_SIZE, PAGE_SIZE);
+ if (!last_pmd_table)
+ panic("%s: Failed to allocate %lu bytes align=%lx\n",
+ __func__, PAGE_SIZE, PAGE_SIZE);
+
+ clear_page(last_pmd_table);
+ mmu_page_ctor(last_pmd_table);
+ }
+
+ return last_pmd_table;
+}
+
+static void __init map_node(int node)
+{
+ unsigned long physaddr, virtaddr, size;
+ pgd_t *pgd_dir;
+ p4d_t *p4d_dir;
+ pud_t *pud_dir;
+ pmd_t *pmd_dir;
+ pte_t *pte_dir;
+
+ size = m68k_memory[node].size;
+ physaddr = m68k_memory[node].addr;
+ virtaddr = (unsigned long)phys_to_virt(physaddr);
+ physaddr |= m68k_supervisor_cachemode |
+ _PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_DIRTY;
+ if (CPU_IS_040_OR_060)
+ physaddr |= _PAGE_GLOBAL040;
+
+ while (size > 0) {
+#ifdef DEBUG
+ if (!(virtaddr & (PMD_SIZE-1)))
+ printk ("\npa=%#lx va=%#lx ", physaddr & PAGE_MASK,
+ virtaddr);
+#endif
+ pgd_dir = pgd_offset_k(virtaddr);
+ if (virtaddr && CPU_IS_020_OR_030) {
+ if (!(virtaddr & (PGDIR_SIZE-1)) &&
+ size >= PGDIR_SIZE) {
+#ifdef DEBUG
+ printk ("[very early term]");
+#endif
+ pgd_val(*pgd_dir) = physaddr;
+ size -= PGDIR_SIZE;
+ virtaddr += PGDIR_SIZE;
+ physaddr += PGDIR_SIZE;
+ continue;
+ }
+ }
+ p4d_dir = p4d_offset(pgd_dir, virtaddr);
+ pud_dir = pud_offset(p4d_dir, virtaddr);
+ if (!pud_present(*pud_dir)) {
+ pmd_dir = kernel_ptr_table();
+#ifdef DEBUG
+ printk ("[new pointer %p]", pmd_dir);
+#endif
+ pud_set(pud_dir, pmd_dir);
+ } else
+ pmd_dir = pmd_offset(pud_dir, virtaddr);
+
+ if (CPU_IS_020_OR_030) {
+ if (virtaddr) {
+#ifdef DEBUG
+ printk ("[early term]");
+#endif
+ pmd_val(*pmd_dir) = physaddr;
+ physaddr += PMD_SIZE;
+ } else {
+ int i;
+#ifdef DEBUG
+ printk ("[zero map]");
+#endif
+ pte_dir = kernel_page_table();
+ pmd_set(pmd_dir, pte_dir);
+
+ pte_val(*pte_dir++) = 0;
+ physaddr += PAGE_SIZE;
+ for (i = 1; i < PTRS_PER_PTE; physaddr += PAGE_SIZE, i++)
+ pte_val(*pte_dir++) = physaddr;
+ }
+ size -= PMD_SIZE;
+ virtaddr += PMD_SIZE;
+ } else {
+ if (!pmd_present(*pmd_dir)) {
+#ifdef DEBUG
+ printk ("[new table]");
+#endif
+ pte_dir = kernel_page_table();
+ pmd_set(pmd_dir, pte_dir);
+ }
+ pte_dir = pte_offset_kernel(pmd_dir, virtaddr);
+
+ if (virtaddr) {
+ if (!pte_present(*pte_dir))
+ pte_val(*pte_dir) = physaddr;
+ } else
+ pte_val(*pte_dir) = 0;
+ size -= PAGE_SIZE;
+ virtaddr += PAGE_SIZE;
+ physaddr += PAGE_SIZE;
+ }
+
+ }
+#ifdef DEBUG
+ printk("\n");
+#endif
+}
+
+/*
+ * Alternate definitions that are compile time constants, for
+ * initializing protection_map. The cachebits are fixed later.
+ */
+#define PAGE_NONE_C __pgprot(_PAGE_PROTNONE | _PAGE_ACCESSED)
+#define PAGE_SHARED_C __pgprot(_PAGE_PRESENT | _PAGE_ACCESSED)
+#define PAGE_COPY_C __pgprot(_PAGE_PRESENT | _PAGE_RONLY | _PAGE_ACCESSED)
+#define PAGE_READONLY_C __pgprot(_PAGE_PRESENT | _PAGE_RONLY | _PAGE_ACCESSED)
+
+static pgprot_t protection_map[16] __ro_after_init = {
+ [VM_NONE] = PAGE_NONE_C,
+ [VM_READ] = PAGE_READONLY_C,
+ [VM_WRITE] = PAGE_COPY_C,
+ [VM_WRITE | VM_READ] = PAGE_COPY_C,
+ [VM_EXEC] = PAGE_READONLY_C,
+ [VM_EXEC | VM_READ] = PAGE_READONLY_C,
+ [VM_EXEC | VM_WRITE] = PAGE_COPY_C,
+ [VM_EXEC | VM_WRITE | VM_READ] = PAGE_COPY_C,
+ [VM_SHARED] = PAGE_NONE_C,
+ [VM_SHARED | VM_READ] = PAGE_READONLY_C,
+ [VM_SHARED | VM_WRITE] = PAGE_SHARED_C,
+ [VM_SHARED | VM_WRITE | VM_READ] = PAGE_SHARED_C,
+ [VM_SHARED | VM_EXEC] = PAGE_READONLY_C,
+ [VM_SHARED | VM_EXEC | VM_READ] = PAGE_READONLY_C,
+ [VM_SHARED | VM_EXEC | VM_WRITE] = PAGE_SHARED_C,
+ [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = PAGE_SHARED_C
+};
+DECLARE_VM_GET_PAGE_PROT
+
+/*
+ * paging_init() continues the virtual memory environment setup which
+ * was begun by the code in arch/head.S.
+ */
+void __init paging_init(void)
+{
+ unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0, };
+ unsigned long min_addr, max_addr;
+ unsigned long addr;
+ int i;
+
+#ifdef DEBUG
+ printk ("start of paging_init (%p, %lx)\n", kernel_pg_dir, availmem);
+#endif
+
+ /* Fix the cache mode in the page descriptors for the 680[46]0. */
+ if (CPU_IS_040_OR_060) {
+ int i;
+#ifndef mm_cachebits
+ mm_cachebits = _PAGE_CACHE040;
+#endif
+ for (i = 0; i < 16; i++)
+ pgprot_val(protection_map[i]) |= _PAGE_CACHE040;
+ }
+
+ min_addr = m68k_memory[0].addr;
+ max_addr = min_addr + m68k_memory[0].size - 1;
+ memblock_add_node(m68k_memory[0].addr, m68k_memory[0].size, 0,
+ MEMBLOCK_NONE);
+ for (i = 1; i < m68k_num_memory;) {
+ if (m68k_memory[i].addr < min_addr) {
+ printk("Ignoring memory chunk at 0x%lx:0x%lx before the first chunk\n",
+ m68k_memory[i].addr, m68k_memory[i].size);
+ printk("Fix your bootloader or use a memfile to make use of this area!\n");
+ m68k_num_memory--;
+ memmove(m68k_memory + i, m68k_memory + i + 1,
+ (m68k_num_memory - i) * sizeof(struct m68k_mem_info));
+ continue;
+ }
+ memblock_add_node(m68k_memory[i].addr, m68k_memory[i].size, i,
+ MEMBLOCK_NONE);
+ addr = m68k_memory[i].addr + m68k_memory[i].size - 1;
+ if (addr > max_addr)
+ max_addr = addr;
+ i++;
+ }
+ m68k_memoffset = min_addr - PAGE_OFFSET;
+ m68k_virt_to_node_shift = fls(max_addr - min_addr) - 6;
+
+ module_fixup(NULL, __start_fixup, __stop_fixup);
+ flush_icache();
+
+ high_memory = phys_to_virt(max_addr) + 1;
+
+ min_low_pfn = availmem >> PAGE_SHIFT;
+ max_pfn = max_low_pfn = (max_addr >> PAGE_SHIFT) + 1;
+
+ /* Reserve kernel text/data/bss and the memory allocated in head.S */
+ memblock_reserve(m68k_memory[0].addr, availmem - m68k_memory[0].addr);
+
+ /*
+ * Map the physical memory available into the kernel virtual
+ * address space. Make sure memblock will not try to allocate
+ * pages beyond the memory we already mapped in head.S
+ */
+ memblock_set_bottom_up(true);
+
+ for (i = 0; i < m68k_num_memory; i++) {
+ m68k_setup_node(i);
+ map_node(i);
+ }
+
+ flush_tlb_all();
+
+ early_memtest(min_addr, max_addr);
+
+ /*
+ * initialize the bad page table and bad page to point
+ * to a couple of allocated pages
+ */
+ empty_zero_page = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
+ if (!empty_zero_page)
+ panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
+ __func__, PAGE_SIZE, PAGE_SIZE);
+
+ /*
+ * Set up SFC/DFC registers
+ */
+ set_fc(USER_DATA);
+
+#ifdef DEBUG
+ printk ("before free_area_init\n");
+#endif
+ for (i = 0; i < m68k_num_memory; i++)
+ if (node_present_pages(i))
+ node_set_state(i, N_NORMAL_MEMORY);
+
+ max_zone_pfn[ZONE_DMA] = memblock_end_of_DRAM();
+ free_area_init(max_zone_pfn);
+}
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