patch-2.4.10 linux/arch/ppc/mm/pgtable.c

• Lines: 361
• Date: Tue Aug 28 06:58:33 2001
• Orig file: v2.4.9/linux/arch/ppc/mm/pgtable.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.4.9/linux/arch/ppc/mm/pgtable.c linux/arch/ppc/mm/pgtable.c
@@ -0,0 +1,360 @@
+/*
+ * BK Id: %F% %I% %G% %U% %#%
+ */
+/*
+ * This file contains the routines setting up the linux page tables.
+ *  -- paulus
+ * 
+ *  Derived from arch/ppc/mm/init.c:
+ *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
+ *
+ *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
+ *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
+ *    Copyright (C) 1996 Paul Mackerras
+ *  Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
+ *
+ *  Derived from "arch/i386/mm/init.c"
+ *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
+ *
+ *  This program is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU General Public License
+ *  as published by the Free Software Foundation; either version
+ *  2 of the License, or (at your option) any later version.
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/vmalloc.h>
+#include <linux/init.h>
+
+#include <asm/pgtable.h>
+#include <asm/pgalloc.h>
+#include <asm/io.h>
+
+#include "mmu_decl.h"
+
+unsigned long ram_phys_base;
+
+unsigned long ioremap_base;
+unsigned long ioremap_bot;
+int io_bat_index;
+
+#ifndef CONFIG_SMP
+struct pgtable_cache_struct quicklists;
+#endif
+
+#if defined(CONFIG_6xx) || defined(CONFIG_POWER3)
+#define HAVE_BATS	1
+#endif
+
+extern char etext[], _stext[];
+
+#ifdef HAVE_BATS
+extern unsigned long v_mapped_by_bats(unsigned long va);
+extern unsigned long p_mapped_by_bats(unsigned long pa);
+void setbat(int index, unsigned long virt, unsigned long phys,
+	    unsigned int size, int flags);
+
+#else /* !HAVE_BATS */
+#define v_mapped_by_bats(x)	(0UL)
+#define p_mapped_by_bats(x)	(0UL)
+#endif /* HAVE_BATS */
+
+#ifndef CONFIG_PPC_ISERIES
+void *
+ioremap(unsigned long addr, unsigned long size)
+{
+	return __ioremap(addr, size, _PAGE_NO_CACHE);
+}
+
+void *
+__ioremap(unsigned long addr, unsigned long size, unsigned long flags)
+{
+	unsigned long p, v, i;
+	int err;
+
+	/*
+	 * Choose an address to map it to.
+	 * Once the vmalloc system is running, we use it.
+	 * Before then, we use space going down from ioremap_base
+	 * (ioremap_bot records where we're up to).
+	 */
+	p = addr & PAGE_MASK;
+	size = PAGE_ALIGN(addr + size) - p;
+
+	/*
+	 * If the address lies within the first 16 MB, assume it's in ISA
+	 * memory space
+	 */
+	if (p < 16*1024*1024)
+		p += _ISA_MEM_BASE;
+
+	/*
+	 * Don't allow anybody to remap normal RAM that we're using.
+	 * mem_init() sets high_memory so only do the check after that.
+	 */
+	if ( mem_init_done && (p < virt_to_phys(high_memory)) )
+	{
+		printk("__ioremap(): phys addr %0lx is RAM lr %p\n", p,
+		       __builtin_return_address(0));
+		return NULL;
+	}
+
+	if (size == 0)
+		return NULL;
+
+	/*
+	 * Is it already mapped?  Perhaps overlapped by a previous
+	 * BAT mapping.  If the whole area is mapped then we're done,
+	 * otherwise remap it since we want to keep the virt addrs for
+	 * each request contiguous.
+	 *
+	 * We make the assumption here that if the bottom and top
+	 * of the range we want are mapped then it's mapped to the
+	 * same virt address (and this is contiguous).
+	 *  -- Cort
+	 */
+	if ((v = p_mapped_by_bats(p)) /*&& p_mapped_by_bats(p+size-1)*/ )
+		goto out;
+	
+	if (mem_init_done) {
+		struct vm_struct *area;
+		area = get_vm_area(size, VM_IOREMAP);
+		if (area == 0)
+			return NULL;
+		v = VMALLOC_VMADDR(area->addr);
+	} else {
+		v = (ioremap_bot -= size);
+	}
+
+	if ((flags & _PAGE_PRESENT) == 0)
+		flags |= _PAGE_KERNEL;
+	if (flags & _PAGE_NO_CACHE)
+		flags |= _PAGE_GUARDED;
+
+	/*
+	 * Should check if it is a candidate for a BAT mapping
+	 */
+
+	err = 0;
+	for (i = 0; i < size && err == 0; i += PAGE_SIZE)
+		err = map_page(v+i, p+i, flags);
+	if (err) {
+		if (mem_init_done)
+			vfree((void *)v);
+		return NULL;
+	}
+
+out:
+	return (void *) (v + (addr & ~PAGE_MASK));
+}
+
+void iounmap(void *addr)
+{
+	/*
+	 * If mapped by BATs then there is nothing to do.
+	 * Calling vfree() generates a benign warning.
+	 */
+	if (v_mapped_by_bats((unsigned long)addr)) return;
+
+	if (addr > high_memory && (unsigned long) addr < ioremap_bot)
+		vfree((void *) (PAGE_MASK & (unsigned long) addr));
+}
+#endif /* CONFIG_PPC_ISERIES */
+
+int
+map_page(unsigned long va, unsigned long pa, int flags)
+{
+	pmd_t *pd;
+	pte_t *pg;
+	int err = -ENOMEM;
+
+	spin_lock(&init_mm.page_table_lock);
+	/* Use upper 10 bits of VA to index the first level map */
+	pd = pmd_offset(pgd_offset_k(va), va);
+	/* Use middle 10 bits of VA to index the second-level map */
+	pg = pte_alloc(&init_mm, pd, va);
+	if (pg != 0) {
+		err = 0;
+		set_pte(pg, mk_pte_phys(pa & PAGE_MASK, __pgprot(flags)));
+		if (mem_init_done)
+			flush_HPTE(0, va, pg);
+	}
+	spin_unlock(&init_mm.page_table_lock);
+	return err;
+}
+
+/*
+ * Map in all of physical memory starting at KERNELBASE.
+ */
+void __init mapin_ram(void)
+{
+	unsigned long v, p, s, f;
+
+#ifdef HAVE_BATS
+	if (!__map_without_bats)
+		bat_mapin_ram();
+#endif /* HAVE_BATS */
+
+	v = KERNELBASE;
+	p = ram_phys_base;
+	for (s = 0; s < total_lowmem; s += PAGE_SIZE) {
+		/* On the MPC8xx, we want the page shared so we
+		 * don't get ASID compares on kernel space.
+		 */
+		f = _PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_SHARED;
+#if defined(CONFIG_KGDB) || defined(CONFIG_XMON)
+		/* Allows stub to set breakpoints everywhere */
+		f |= _PAGE_RW | _PAGE_DIRTY;
+#else
+		if ((char *) v < _stext || (char *) v >= etext)
+			f |= _PAGE_RW | _PAGE_DIRTY;
+#ifndef CONFIG_8xx
+		else
+			/* On the powerpc (not 8xx), no user access
+			   forces R/W kernel access */
+			f |= _PAGE_USER;
+#endif /* CONFIG_8xx */
+#endif /* CONFIG_KGDB */
+		map_page(v, p, f);
+		v += PAGE_SIZE;
+		p += PAGE_SIZE;
+	}
+}
+
+/* is x a power of 2? */
+#define is_power_of_2(x)	((x) != 0 && (((x) & ((x) - 1)) == 0))
+
+/*
+ * Set up a mapping for a block of I/O.
+ * virt, phys, size must all be page-aligned.
+ * This should only be called before ioremap is called.
+ */
+void __init io_block_mapping(unsigned long virt, unsigned long phys,
+			     unsigned int size, int flags)
+{
+	int i;
+
+	if (virt > KERNELBASE && virt < ioremap_bot)
+		ioremap_bot = ioremap_base = virt;
+
+#ifdef HAVE_BATS
+	/*
+	 * Use a BAT for this if possible...
+	 */
+	if (io_bat_index < 2 && is_power_of_2(size)
+	    && (virt & (size - 1)) == 0 && (phys & (size - 1)) == 0) {
+		setbat(io_bat_index, virt, phys, size, flags);
+		++io_bat_index;
+		return;
+	}
+#endif /* HAVE_BATS */
+
+	/* No BATs available, put it in the page tables. */
+	for (i = 0; i < size; i += PAGE_SIZE)
+		map_page(virt + i, phys + i, flags);
+}
+
+/* Scan the real Linux page tables and return a PTE pointer for
+ * a virtual address in a context.
+ * Returns true (1) if PTE was found, zero otherwise.  The pointer to
+ * the PTE pointer is unmodified if PTE is not found.
+ */
+int
+get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep)
+{
+        pgd_t	*pgd;
+        pmd_t	*pmd;
+        pte_t	*pte;
+        int     retval = 0;
+
+        pgd = pgd_offset(mm, addr & PAGE_MASK);
+        if (pgd) {
+                pmd = pmd_offset(pgd, addr & PAGE_MASK);
+                if (pmd_present(*pmd)) {
+                        pte = pte_offset(pmd, addr & PAGE_MASK);
+                        if (pte) {
+				retval = 1;
+				*ptep = pte;
+                        }
+                }
+        }
+        return(retval);
+}
+
+/* Find physical address for this virtual address.  Normally used by
+ * I/O functions, but anyone can call it.
+ */
+unsigned long iopa(unsigned long addr)
+{
+	unsigned long pa;
+
+	/* I don't know why this won't work on PMacs or CHRP.  It
+	 * appears there is some bug, or there is some implicit
+	 * mapping done not properly represented by BATs or in page
+	 * tables.......I am actively working on resolving this, but
+	 * can't hold up other stuff.  -- Dan
+	 */
+	pte_t *pte;
+	struct mm_struct *mm;
+
+	/* Check the BATs */
+	pa = v_mapped_by_bats(addr);
+	if (pa)
+		return pa;
+
+	/* Allow mapping of user addresses (within the thread)
+	 * for DMA if necessary.
+	 */
+	if (addr < TASK_SIZE)
+		mm = current->mm;
+	else
+		mm = &init_mm;
+	
+	pa = 0;
+	if (get_pteptr(mm, addr, &pte))
+		pa = (pte_val(*pte) & PAGE_MASK) | (addr & ~PAGE_MASK);
+
+	return(pa);
+}
+
+/* This is will find the virtual address for a physical one....
+ * Swiped from APUS, could be dangerous :-).
+ * This is only a placeholder until I really find a way to make this
+ * work.  -- Dan
+ */
+unsigned long
+mm_ptov (unsigned long paddr)
+{
+	unsigned long ret;
+#if 0
+	if (paddr < 16*1024*1024)
+		ret = ZTWO_VADDR(paddr);
+	else {
+		int i;
+
+		for (i = 0; i < kmap_chunk_count;){
+			unsigned long phys = kmap_chunks[i++];
+			unsigned long size = kmap_chunks[i++];
+			unsigned long virt = kmap_chunks[i++];
+			if (paddr >= phys
+			    && paddr < (phys + size)){
+				ret = virt + paddr - phys;
+				goto exit;
+			}
+		}
+		
+		ret = (unsigned long) __va(paddr);
+	}
+exit:
+#ifdef DEBUGPV
+	printk ("PTOV(%lx)=%lx\n", paddr, ret);
+#endif
+#else
+	ret = (unsigned long)paddr + KERNELBASE;
+#endif
+	return ret;
+}
+