patch-1.3.94 linux/arch/m68k/mm/init.c

• Lines: 546
• Date: Thu Apr 18 03:00:00 1996
• Orig file: v1.3.93/linux/arch/m68k/mm/init.c
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v1.3.93/linux/arch/m68k/mm/init.c linux/arch/m68k/mm/init.c
@@ -0,0 +1,545 @@
+/*
+ *  linux/arch/m68k/mm/init.c
+ *
+ *  Copyright (C) 1995  Hamish Macdonald
+ */
+
+#include <linux/config.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>
+#ifdef CONFIG_BLK_DEV_INITRD
+#include <linux/blk.h>
+#endif
+
+#include <asm/segment.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <asm/system.h>
+#include <asm/bootinfo.h>
+#include <asm/machdep.h>
+
+extern void die_if_kernel(char *,struct pt_regs *,long);
+extern void show_net_buffers(void);
+extern unsigned long mm_phys_to_virt (unsigned long addr);
+extern char *rd_start;
+extern int rd_doload;
+
+unsigned long ramdisk_length;
+
+/*
+ * BAD_PAGE is the page that is used for page faults when linux
+ * is out-of-memory. Older versions of linux just did a
+ * do_exit(), but using this instead means there is less risk
+ * for a process dying in kernel mode, possibly leaving a inode
+ * unused etc..
+ *
+ * BAD_PAGETABLE is the accompanying page-table: it is initialized
+ * to point to BAD_PAGE entries.
+ *
+ * ZERO_PAGE is a special page that is used for zero-initialized
+ * data and COW.
+ */
+static unsigned long empty_bad_page_table;
+
+pte_t *__bad_pagetable(void)
+{
+    memset((void *)empty_bad_page_table, 0, PAGE_SIZE);
+    return (pte_t *)empty_bad_page_table;
+}
+
+static unsigned long empty_bad_page;
+
+pte_t __bad_page(void)
+{
+    memset ((void *)empty_bad_page, 0, PAGE_SIZE);
+    return pte_mkdirty(mk_pte(empty_bad_page, PAGE_SHARED));
+}
+
+unsigned long empty_zero_page;
+
+void show_mem(void)
+{
+    unsigned long i;
+    int free = 0, total = 0, reserved = 0, nonshared = 0, shared = 0;
+
+    printk("\nMem-info:\n");
+    show_free_areas();
+    printk("Free swap:       %6dkB\n",nr_swap_pages<<(PAGE_SHIFT-10));
+    i = high_memory >> PAGE_SHIFT;
+    while (i-- > 0) {
+	total++;
+	if (PageReserved(mem_map+i))
+	    reserved++;
+	else if (!mem_map[i].count)
+	    free++;
+	else if (mem_map[i].count == 1)
+	    nonshared++;
+	else
+	    shared += mem_map[i].count-1;
+    }
+    printk("%d pages of RAM\n",total);
+    printk("%d free pages\n",free);
+    printk("%d reserved pages\n",reserved);
+    printk("%d pages nonshared\n",nonshared);
+    printk("%d pages shared\n",shared);
+    show_buffers();
+#ifdef CONFIG_NET
+    show_net_buffers();
+#endif
+}
+
+#if 0 /* The 68030 doesn't care about reserved bits. */
+/*
+ * 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;
+#endif
+
+pte_t *kernel_page_table (unsigned long *memavailp)
+{
+	pte_t *ptablep;
+
+	ptablep = (pte_t *)*memavailp;
+	*memavailp += PAGE_SIZE;
+
+	nocache_page ((unsigned long)ptablep);
+
+	return ptablep;
+}
+
+static unsigned long map_chunk (unsigned long addr,
+				unsigned long size,
+				unsigned long *memavailp)
+{
+#define ONEMEG	(1024*1024)
+#define L3TREESIZE (256*1024)
+
+	int is040 = m68k_is040or060;
+	static unsigned long mem_mapped = 0;
+	static unsigned long virtaddr = 0;
+	static pte_t *ktablep = NULL;
+	unsigned long *kpointerp;
+	unsigned long physaddr;
+	extern pte_t *kpt;
+	int pindex;   /* index into pointer table */
+	pgd_t *page_dir = pgd_offset_k (virtaddr);
+
+	if (!pgd_present (*page_dir)) {
+		/* we need a new pointer table */
+		kpointerp = (unsigned long *) get_kpointer_table ();
+		pgd_set (page_dir, (pmd_t *) kpointerp);
+		memset (kpointerp, 0, PTRS_PER_PMD * sizeof (pmd_t));
+	}
+	else
+		kpointerp = (unsigned long *) pgd_page (*page_dir);
+
+	/*
+	 * pindex is the offset into the pointer table for the
+	 * descriptors for the current virtual address being mapped.
+	 */
+	pindex = (virtaddr >> 18) & 0x7f;
+
+#ifdef DEBUG
+	printk ("mm=%ld, kernel_pg_dir=%p, kpointerp=%p, pindex=%d\n",
+		mem_mapped, kernel_pg_dir, kpointerp, pindex);
+#endif
+
+	/*
+	 * if this is running on an '040, we already allocated a page
+	 * table for the first 4M.  The address is stored in kpt by
+	 * arch/head.S
+	 *
+	 */
+	if (is040 && mem_mapped == 0)
+		ktablep = kpt;
+
+	for (physaddr = addr;
+	     physaddr < addr + size;
+	     mem_mapped += L3TREESIZE, virtaddr += L3TREESIZE) {
+
+#ifdef DEBUG
+		printk ("pa=%#lx va=%#lx ", physaddr, virtaddr);
+#endif
+
+		if (pindex > 127 && mem_mapped >= 32*ONEMEG) {
+			/* we need a new pointer table every 32M */
+#ifdef DEBUG
+			printk ("[new pointer]");
+#endif
+
+			kpointerp = (unsigned long *)get_kpointer_table ();
+			pgd_set(pgd_offset_k(virtaddr), (pmd_t *)kpointerp);
+			pindex = 0;
+		}
+
+		if (is040) {
+			int i;
+			unsigned long ktable;
+
+			/* Don't map the first 4 MB again. The pagetables
+			 * for this range have already been initialized
+			 * in boot/head.S. Otherwise the pages used for
+			 * tables would be reinitialized to copyback mode.
+			 */
+
+			if (mem_mapped < 4 * ONEMEG)
+			{
+#ifdef DEBUG
+				printk ("Already initialized\n");
+#endif
+				physaddr += L3TREESIZE;
+				pindex++;
+				continue;
+			}
+#ifdef DEBUG
+			printk ("[setup table]");
+#endif
+
+			/*
+			 * 68040, use page tables pointed to by the
+			 * kernel pointer table.
+			 */
+
+			if ((pindex & 15) == 0) {
+				/* Need new page table every 4M on the '040 */
+#ifdef DEBUG
+				printk ("[new table]");
+#endif
+				ktablep = kernel_page_table (memavailp);
+			}
+
+			ktable = VTOP(ktablep);
+
+			/*
+			 * initialize section of the page table mapping
+			 * this 256K portion.
+			 */
+			for (i = 0; i < 64; i++) {
+				pte_val(ktablep[i]) = physaddr | _PAGE_PRESENT
+					| _PAGE_CACHE040 | _PAGE_GLOBAL040;
+				physaddr += PAGE_SIZE;
+			}
+			ktablep += 64;
+
+			/*
+			 * make the kernel pointer table point to the
+			 * kernel page table.  Each entries point to a
+			 * 64 entry section of the page table.
+			 */
+
+			kpointerp[pindex++] = ktable | _PAGE_TABLE;
+		} else {
+			/*
+			 * 68030, use early termination page descriptors.
+			 * Each one points to 64 pages (256K).
+			 */
+#ifdef DEBUG
+			printk ("[early term] ");
+#endif
+			if (virtaddr == 0UL) {
+				/* map the first 256K using a 64 entry
+				 * 3rd level page table.
+				 * UNMAP the first entry to trap
+				 * zero page (NULL pointer) references
+				 */
+				int i;
+				unsigned long *tbl;
+				
+				tbl = (unsigned long *)get_kpointer_table();
+
+				kpointerp[pindex++] = VTOP(tbl) | _PAGE_TABLE;
+
+				for (i = 0; i < 64; i++, physaddr += PAGE_SIZE)
+					tbl[i] = physaddr | _PAGE_PRESENT;
+				
+				/* unmap the zero page */
+				tbl[0] = 0;
+			} else {
+				/* not the first 256K */
+				kpointerp[pindex++] = physaddr | _PAGE_PRESENT;
+#ifdef DEBUG
+				printk ("%lx=%lx ", VTOP(&kpointerp[pindex-1]),
+					kpointerp[pindex-1]);
+#endif
+				physaddr += 64 * PAGE_SIZE;
+			}
+		}
+#ifdef DEBUG
+		printk ("\n");
+#endif
+	}
+
+	return mem_mapped;
+}
+
+extern unsigned long free_area_init(unsigned long, unsigned long);
+
+extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
+
+/*
+ * paging_init() continues the virtual memory environment setup which
+ * was begun by the code in arch/head.S.
+ * The parameters are pointers to where to stick the starting and ending
+ * addresses  of available kernel virtual memory.
+ */
+unsigned long paging_init(unsigned long start_mem, unsigned long end_mem)
+{
+	int chunk;
+	unsigned long mem_avail = 0;
+	/* pointer to page table for kernel stacks */
+	extern unsigned long availmem;
+
+#ifdef DEBUG
+	{
+		extern pte_t *kpt;
+		printk ("start of paging_init (%p, %p, %lx, %lx, %lx)\n",
+			kernel_pg_dir, kpt, availmem, start_mem, end_mem);
+	}
+#endif
+
+#if 0
+	/*
+	 * Setup cache bits
+	 */
+	mm_cachebits = m68k_is040or060 ? _PAGE_CACHE040 : 0;
+
+	/* Initialize protection map.  */
+	protection_map[0] = PAGE_READONLY;
+	protection_map[1] = PAGE_READONLY;
+	protection_map[2] = PAGE_COPY;
+	protection_map[3] = PAGE_COPY;
+	protection_map[4] = PAGE_READONLY;
+	protection_map[5] = PAGE_READONLY;
+	protection_map[6] = PAGE_COPY;
+	protection_map[7] = PAGE_COPY;
+	protection_map[8] = PAGE_READONLY;
+	protection_map[9] = PAGE_READONLY;
+	protection_map[10] = PAGE_SHARED;
+	protection_map[11] = PAGE_SHARED;
+	protection_map[12] = PAGE_READONLY;
+	protection_map[13] = PAGE_READONLY;
+	protection_map[14] = PAGE_SHARED;
+	protection_map[15] = PAGE_SHARED;
+#endif
+
+	/*
+	 * Map the physical memory available into the kernel virtual
+	 * address space.  It may allocate some memory for page
+	 * tables and thus modify availmem.
+	 */
+
+	for (chunk = 0; chunk < boot_info.num_memory; chunk++) {
+		mem_avail = map_chunk (boot_info.memory[chunk].addr,
+				       boot_info.memory[chunk].size,
+				       &availmem);
+
+	}
+	flush_tlb_all();
+#ifdef DEBUG
+	printk ("memory available is %ldKB\n", mem_avail >> 10);
+#endif
+
+	/*
+	 * virtual address after end of kernel
+	 * "availmem" is setup by the code in head.S.
+	 */
+	start_mem = availmem;
+
+#ifdef DEBUG
+	printk ("start_mem is %#lx\nvirtual_end is %#lx\n",
+		start_mem, end_mem);
+#endif
+
+	/*
+	 * initialize the bad page table and bad page to point
+	 * to a couple of allocated pages
+	 */
+	empty_bad_page_table = start_mem;
+	start_mem += PAGE_SIZE;
+	empty_bad_page = start_mem;
+	start_mem += PAGE_SIZE;
+	empty_zero_page = start_mem;
+	start_mem += PAGE_SIZE;
+	memset((void *)empty_zero_page, 0, PAGE_SIZE);
+
+#if 0
+	/* 
+	 * allocate the "swapper" page directory and
+	 * record in task 0 (swapper) tss 
+	 */
+	swapper_pg_dir = (pgd_t *)get_kpointer_table();
+
+	init_mm.pgd = swapper_pg_dir;
+#endif
+
+	memset (swapper_pg_dir, 0, sizeof(pgd_t)*PTRS_PER_PGD);
+	task[0]->tss.pagedir_v = (unsigned long *)swapper_pg_dir;
+	task[0]->tss.pagedir_p = VTOP (swapper_pg_dir);
+
+#ifdef DEBUG
+	printk ("task 0 pagedir at %p virt, %#lx phys\n",
+		task[0]->tss.pagedir_v, task[0]->tss.pagedir_p);
+#endif
+
+	/* setup CPU root pointer for swapper task */
+	task[0]->tss.crp[0] = 0x80000000 | _PAGE_SHORT;
+	task[0]->tss.crp[1] = task[0]->tss.pagedir_p;
+
+	if (m68k_is040or060)
+		asm ("movel %0,%/d0\n\t"
+		     ".long 0x4e7b0806" /* movec d0,urp */
+		     : /* no outputs */
+		     : "g" (task[0]->tss.crp[1])
+		     : "d0");
+	else
+		asm ("pmove %0@,%/crp"
+		     : /* no outputs */
+		     : "a" (task[0]->tss.crp));
+
+#ifdef DEBUG
+	printk ("set crp\n");
+#endif
+
+	/*
+	 * Set up SFC/DFC registers (user data space)
+	 */
+	set_fs (USER_DS);
+
+#ifdef DEBUG
+	printk ("before free_area_init\n");
+#endif
+
+#ifndef CONFIG_BLK_DEV_INITRD
+	/*
+	 * Since the initialization of the ramdisk's has been changed
+	 * so it fits the new driver initialization scheme, we have to
+	 * make room for our preloaded image here, instead of doing it
+	 * in rd_init() as we cannot kmalloc() a block large enough
+	 * for the image.
+	 */
+
+	ramdisk_length = boot_info.ramdisk_size * 1024;
+
+	if ((ramdisk_length > 0) && (ROOT_DEV == 0)) {
+	  char *rdp;	     /* current location of ramdisk */
+
+	  rd_start = (char *) start_mem;
+
+	  /* get current address of ramdisk */
+	  rdp = (char *)mm_phys_to_virt (boot_info.ramdisk_addr);
+
+	  /* copy the ram disk image */
+	  memcpy (rd_start, rdp, ramdisk_length);
+	  start_mem += ramdisk_length;
+	  rd_doload = 1;     /* tell rd_load to load this thing */
+	}
+#endif
+
+	return free_area_init (start_mem, end_mem);
+}
+
+void mem_init(unsigned long start_mem, unsigned long end_mem)
+{
+	int codepages = 0;
+	int reservedpages = 0;
+	int datapages = 0;
+	unsigned long tmp;
+	extern int _etext;
+
+	end_mem &= PAGE_MASK;
+	high_memory = end_mem;
+
+	start_mem = PAGE_ALIGN(start_mem);
+	while (start_mem < high_memory) {
+		clear_bit(PG_reserved, &mem_map[MAP_NR(start_mem)].flags);
+		start_mem += PAGE_SIZE;
+	}
+
+#ifdef CONFIG_ATARI
+
+	if (MACH_IS_ATARI) {
+
+		/* If the page with physical address 0 isn't the first kernel
+		 * code page, it has to be reserved because the first 2 KB of
+		 * ST-Ram can only be accessed from supervisor mode by
+		 * hardware.
+		 */
+
+		unsigned long virt0 = PTOV( 0 ), adr;
+		extern unsigned long rsvd_stram_beg, rsvd_stram_end;
+		
+		if (virt0 != 0) {
+
+			set_bit(PG_reserved, &mem_map[MAP_NR(virt0)].flags);
+
+			/* Also, reserve all pages that have been marked by
+			 * stram_alloc() (e.g. for the screen memory). (This may
+			 * treat the first ST-Ram page a second time, but that
+			 * doesn't hurt...) */
+			
+			rsvd_stram_end += PAGE_SIZE - 1;
+			rsvd_stram_end &= PAGE_MASK;
+			rsvd_stram_beg &= PAGE_MASK;
+			for( adr = rsvd_stram_beg; adr < rsvd_stram_end; adr += PAGE_SIZE )
+				set_bit(PG_reserved, &mem_map[MAP_NR(adr)].flags);
+		}
+	}
+	
+#endif
+#ifdef DEBUG
+	printk ("task[0] root table is %p\n", task[0]->tss.pagedir_v);
+#endif
+
+	for (tmp = 0 ; tmp < end_mem ; tmp += PAGE_SIZE) {
+		if (VTOP (tmp) >= mach_max_dma_address)
+			clear_bit(PG_DMA, &mem_map[MAP_NR(tmp)].flags);
+		if (PageReserved(mem_map+MAP_NR(tmp))) {
+			if (tmp < (unsigned long)&_etext)
+				codepages++;
+			else
+				datapages++;
+			continue;
+		}
+		mem_map[MAP_NR(tmp)].count = 1;
+#ifdef CONFIG_BLK_DEV_INITRD
+		if (!initrd_start || (tmp < initrd_start || tmp >= initrd_end))
+#endif
+			free_page(tmp);
+	}
+	tmp = nr_free_pages << PAGE_SHIFT;
+	printk("Memory: %luk/%luk available (%dk kernel code, %dk reserved, %dk data)\n",
+	       tmp >> 10,
+	       high_memory >> 10,
+	       codepages << (PAGE_SHIFT-10),
+	       reservedpages << (PAGE_SHIFT-10),
+	       datapages << (PAGE_SHIFT-10));
+}
+
+void si_meminfo(struct sysinfo *val)
+{
+    unsigned long i;
+
+    i = high_memory >> PAGE_SHIFT;
+    val->totalram = 0;
+    val->sharedram = 0;
+    val->freeram = nr_free_pages << PAGE_SHIFT;
+    val->bufferram = buffermem;
+    while (i-- > 0) {
+	if (PageReserved(mem_map+i))
+	    continue;
+	val->totalram++;
+	if (!mem_map[i].count)
+	    continue;
+	val->sharedram += mem_map[i].count-1;
+    }
+    val->totalram <<= PAGE_SHIFT;
+    val->sharedram <<= PAGE_SHIFT;
+    return;
+}