4368902bb9
Implement ioremap_prot() to allow mapping IO memory with variable protection via TLB. Implementing this allows the /dev/mem driver to use its generic access() VMA callback, which in turn allows ptrace to examine data in memory mapped regions mapped via /dev/mem, such as Arc DCCM. The end result is that it is possible to examine values of variables placed into DCCM in user space programs via GDB. CC: Alexey Brodkin <Alexey.Brodkin@synopsys.com> CC: Noam Camus <noamc@ezchip.com> Acked-by: Vineet Gupta <vgupta@synopsys.com> Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com> Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
91 lines
2.3 KiB
C
91 lines
2.3 KiB
C
/*
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* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/vmalloc.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/io.h>
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#include <linux/mm.h>
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#include <linux/slab.h>
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#include <asm/cache.h>
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void __iomem *ioremap(unsigned long paddr, unsigned long size)
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{
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unsigned long end;
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/* Don't allow wraparound or zero size */
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end = paddr + size - 1;
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if (!size || (end < paddr))
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return NULL;
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/* If the region is h/w uncached, avoid MMU mappings */
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if (paddr >= ARC_UNCACHED_ADDR_SPACE)
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return (void __iomem *)paddr;
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return ioremap_prot(paddr, size, PAGE_KERNEL_NO_CACHE);
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}
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EXPORT_SYMBOL(ioremap);
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/*
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* ioremap with access flags
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* Cache semantics wise it is same as ioremap - "forced" uncached.
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* However unline vanilla ioremap which bypasses ARC MMU for addresses in
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* ARC hardware uncached region, this one still goes thru the MMU as caller
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* might need finer access control (R/W/X)
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*/
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void __iomem *ioremap_prot(phys_addr_t paddr, unsigned long size,
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unsigned long flags)
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{
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void __iomem *vaddr;
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struct vm_struct *area;
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unsigned long off, end;
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pgprot_t prot = __pgprot(flags);
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/* Don't allow wraparound, zero size */
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end = paddr + size - 1;
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if ((!size) || (end < paddr))
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return NULL;
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/* An early platform driver might end up here */
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if (!slab_is_available())
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return NULL;
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/* force uncached */
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prot = pgprot_noncached(prot);
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/* Mappings have to be page-aligned */
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off = paddr & ~PAGE_MASK;
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paddr &= PAGE_MASK;
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size = PAGE_ALIGN(end + 1) - paddr;
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/*
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* Ok, go for it..
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*/
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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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area->phys_addr = paddr;
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vaddr = (void __iomem *)area->addr;
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if (ioremap_page_range((unsigned long)vaddr,
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(unsigned long)vaddr + size, paddr, prot)) {
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vunmap((void __force *)vaddr);
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return NULL;
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}
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return (void __iomem *)(off + (char __iomem *)vaddr);
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}
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EXPORT_SYMBOL(ioremap_prot);
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void iounmap(const void __iomem *addr)
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{
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if (addr >= (void __force __iomem *)ARC_UNCACHED_ADDR_SPACE)
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return;
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vfree((void *)(PAGE_MASK & (unsigned long __force)addr));
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}
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EXPORT_SYMBOL(iounmap);
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