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872fec16d9
First step in pushing down the page_table_lock. init_mm.page_table_lock has been used throughout the architectures (usually for ioremap): not to serialize kernel address space allocation (that's usually vmlist_lock), but because pud_alloc,pmd_alloc,pte_alloc_kernel expect caller holds it. Reverse that: don't lock or unlock init_mm.page_table_lock in any of the architectures; instead rely on pud_alloc,pmd_alloc,pte_alloc_kernel to take and drop it when allocating a new one, to check lest a racing task already did. Similarly no page_table_lock in vmalloc's map_vm_area. Some temporary ugliness in __pud_alloc and __pmd_alloc: since they also handle user mms, which are converted only by a later patch, for now they have to lock differently according to whether or not it's init_mm. If sources get muddled, there's a danger that an arch source taking init_mm.page_table_lock will be mixed with common source also taking it (or neither take it). So break the rules and make another change, which should break the build for such a mismatch: remove the redundant mm arg from pte_alloc_kernel (ppc64 scrapped its distinct ioremap_mm in 2.6.13). Exceptions: arm26 used pte_alloc_kernel on user mm, now pte_alloc_map; ia64 used pte_alloc_map on init_mm, now pte_alloc_kernel; parisc had bad args to pmd_alloc and pte_alloc_kernel in unused USE_HPPA_IOREMAP code; ppc64 map_io_page forgot to unlock on failure; ppc mmu_mapin_ram and ppc64 im_free took page_table_lock for no good reason. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
137 lines
3.3 KiB
C
137 lines
3.3 KiB
C
/*
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* arch/s390/mm/ioremap.c
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*
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* S390 version
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* Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
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* Author(s): Hartmut Penner (hp@de.ibm.com)
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*
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* Derived from "arch/i386/mm/extable.c"
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* (C) Copyright 1995 1996 Linus Torvalds
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*
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* Re-map IO memory to kernel address space so that we can access it.
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* This is needed for high PCI addresses that aren't mapped in the
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* 640k-1MB IO memory area on PC's
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*/
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#include <linux/vmalloc.h>
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#include <linux/mm.h>
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#include <asm/io.h>
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#include <asm/pgalloc.h>
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#include <asm/cacheflush.h>
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#include <asm/tlbflush.h>
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static inline void remap_area_pte(pte_t * pte, unsigned long address, unsigned long size,
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unsigned long phys_addr, unsigned long flags)
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{
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unsigned long end;
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unsigned long pfn;
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address &= ~PMD_MASK;
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end = address + size;
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if (end > PMD_SIZE)
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end = PMD_SIZE;
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if (address >= end)
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BUG();
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pfn = phys_addr >> PAGE_SHIFT;
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do {
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if (!pte_none(*pte)) {
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printk("remap_area_pte: page already exists\n");
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BUG();
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}
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set_pte(pte, pfn_pte(pfn, __pgprot(flags)));
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address += PAGE_SIZE;
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pfn++;
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pte++;
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} while (address && (address < end));
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}
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static inline int remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned long size,
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unsigned long phys_addr, unsigned long flags)
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{
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unsigned long end;
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address &= ~PGDIR_MASK;
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end = address + size;
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if (end > PGDIR_SIZE)
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end = PGDIR_SIZE;
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phys_addr -= address;
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if (address >= end)
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BUG();
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do {
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pte_t * pte = pte_alloc_kernel(pmd, address);
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if (!pte)
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return -ENOMEM;
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remap_area_pte(pte, address, end - address, address + phys_addr, flags);
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address = (address + PMD_SIZE) & PMD_MASK;
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pmd++;
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} while (address && (address < end));
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return 0;
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}
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static int remap_area_pages(unsigned long address, unsigned long phys_addr,
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unsigned long size, unsigned long flags)
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{
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int error;
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pgd_t * dir;
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unsigned long end = address + size;
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phys_addr -= address;
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dir = pgd_offset(&init_mm, address);
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flush_cache_all();
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if (address >= end)
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BUG();
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do {
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pmd_t *pmd;
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pmd = pmd_alloc(&init_mm, dir, address);
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error = -ENOMEM;
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if (!pmd)
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break;
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if (remap_area_pmd(pmd, address, end - address,
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phys_addr + address, flags))
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break;
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error = 0;
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address = (address + PGDIR_SIZE) & PGDIR_MASK;
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dir++;
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} while (address && (address < end));
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flush_tlb_all();
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return 0;
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}
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/*
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* Generic mapping function (not visible outside):
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*/
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/*
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* Remap an arbitrary physical address space into the kernel virtual
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* address space. Needed when the kernel wants to access high addresses
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* directly.
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*/
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void * __ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags)
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{
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void * addr;
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struct vm_struct * area;
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if (phys_addr < virt_to_phys(high_memory))
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return phys_to_virt(phys_addr);
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if (phys_addr & ~PAGE_MASK)
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return NULL;
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size = PAGE_ALIGN(size);
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if (!size || size > phys_addr + size)
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return NULL;
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area = get_vm_area(size, VM_IOREMAP);
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if (!area)
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return NULL;
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addr = area->addr;
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if (remap_area_pages((unsigned long) addr, phys_addr, size, flags)) {
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vfree(addr);
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return NULL;
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}
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return addr;
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}
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void iounmap(void *addr)
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{
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if (addr > high_memory)
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vfree(addr);
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}
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