diff options
Diffstat (limited to 'arch/m68k/mm/motorola.c')
-rw-r--r-- | arch/m68k/mm/motorola.c | 481 |
1 files changed, 481 insertions, 0 deletions
diff --git a/arch/m68k/mm/motorola.c b/arch/m68k/mm/motorola.c new file mode 100644 index 000000000..3a653f0a4 --- /dev/null +++ b/arch/m68k/mm/motorola.c @@ -0,0 +1,481 @@ +// 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> +#include <asm/dma.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 +} + +/* + * 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; + memblock_add_node(m68k_memory[0].addr, m68k_memory[0].size, 0); + 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); + addr = m68k_memory[i].addr + m68k_memory[i].size; + if (addr > max_addr) + max_addr = addr; + i++; + } + m68k_memoffset = min_addr - PAGE_OFFSET; + m68k_virt_to_node_shift = fls(max_addr - min_addr - 1) - 6; + + module_fixup(NULL, __start_fixup, __stop_fixup); + flush_icache(); + + high_memory = phys_to_virt(max_addr); + + min_low_pfn = availmem >> PAGE_SHIFT; + max_pfn = max_low_pfn = max_addr >> PAGE_SHIFT; + + /* 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(); + + /* + * 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_fs(KERNEL_DS); + +#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); +} |