/* * This file contains the routines setting up the linux page tables. * * Copyright (C) 2008 Michal Simek * Copyright (C) 2008 PetaLogix * * Copyright (C) 2007 Xilinx, Inc. All rights reserved. * * Derived from arch/ppc/mm/pgtable.c: * -- 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 file is subject to the terms and conditions of the GNU General * Public License. See the file COPYING in the main directory of this * archive for more details. * */ #include <linux/export.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 <linux/io.h> #include <asm/mmu.h> #include <asm/sections.h> #include <asm/fixmap.h> unsigned long ioremap_base; unsigned long ioremap_bot; EXPORT_SYMBOL(ioremap_bot); #ifndef CONFIG_SMP struct pgtable_cache_struct quicklists; #endif static void __iomem *__ioremap(phys_addr_t addr, unsigned long size, unsigned long flags) { unsigned long v, i; phys_addr_t p; 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; /* * Don't allow anybody to remap normal RAM that we're using. * mem_init() sets high_memory so only do the check after that. * * However, allow remap of rootfs: TBD */ if (mem_init_done && p >= memory_start && p < virt_to_phys(high_memory) && !(p >= virt_to_phys((unsigned long)&__bss_stop) && p < virt_to_phys((unsigned long)__bss_stop))) { pr_warn("__ioremap(): phys addr "PTE_FMT" is RAM lr %pf\n", (unsigned long)p, __builtin_return_address(0)); return NULL; } if (size == 0) return NULL; /* * Is it already mapped? 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 (mem_init_done) { struct vm_struct *area; area = get_vm_area(size, VM_IOREMAP); if (area == NULL) return NULL; v = (unsigned long) area->addr; } else { v = (ioremap_bot -= size); } if ((flags & _PAGE_PRESENT) == 0) flags |= _PAGE_KERNEL; if (flags & _PAGE_NO_CACHE) flags |= _PAGE_GUARDED; 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; } return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK)); } void __iomem *ioremap(phys_addr_t addr, unsigned long size) { return __ioremap(addr, size, _PAGE_NO_CACHE); } EXPORT_SYMBOL(ioremap); void iounmap(void __iomem *addr) { if ((__force void *)addr > high_memory && (unsigned long) addr < ioremap_bot) vfree((void *) (PAGE_MASK & (unsigned long) addr)); } EXPORT_SYMBOL(iounmap); int map_page(unsigned long va, phys_addr_t pa, int flags) { pmd_t *pd; pte_t *pg; int err = -ENOMEM; /* 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_kernel(pd, va); /* from powerpc - pgtable.c */ /* pg = pte_alloc_kernel(&init_mm, pd, va); */ if (pg != NULL) { err = 0; set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT, __pgprot(flags))); if (unlikely(mem_init_done)) _tlbie(va); } return err; } /* * Map in all of physical memory starting at CONFIG_KERNEL_START. */ void __init mapin_ram(void) { unsigned long v, p, s, f; v = CONFIG_KERNEL_START; p = memory_start; for (s = 0; s < lowmem_size; s += PAGE_SIZE) { f = _PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_SHARED | _PAGE_HWEXEC; if ((char *) v < _stext || (char *) v >= _etext) f |= _PAGE_WRENABLE; else /* On the MicroBlaze, no user access forces R/W kernel access */ f |= _PAGE_USER; 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)) /* 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. */ static 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_kernel(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; pte_t *pte; struct mm_struct *mm; /* 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; } __init_refok pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address) { pte_t *pte; if (mem_init_done) { pte = (pte_t *)__get_free_page(GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO); } else { pte = (pte_t *)early_get_page(); if (pte) clear_page(pte); } return pte; } void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t flags) { unsigned long address = __fix_to_virt(idx); if (idx >= __end_of_fixed_addresses) BUG(); map_page(address, phys, pgprot_val(flags)); }