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18e780b4e6
Add special hook for architecture to verify addr, size or prot
when ioremap() or iounmap(), which will make the generic ioremap
more useful.
ioremap_allowed() return a bool,
- true means continue to remap
- false means skip remap and return directly
iounmap_allowed() return a bool,
- true means continue to vunmap
- false code means skip vunmap and return directly
Meanwhile, only vunmap the address when it is in vmalloc area
as the generic ioremap only returns vmalloc addresses.
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Baoquan He <bhe@redhat.com>
Link: https://lore.kernel.org/r/20220607125027.44946-5-wangkefeng.wang@huawei.com
Signed-off-by: Will Deacon <will@kernel.org>
61 lines
1.4 KiB
C
61 lines
1.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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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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* (C) Copyright 1995 1996 Linus Torvalds
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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 <linux/io.h>
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#include <linux/export.h>
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void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size,
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unsigned long prot)
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{
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unsigned long offset, vaddr;
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phys_addr_t last_addr;
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struct vm_struct *area;
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/* Disallow wrap-around or zero size */
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last_addr = phys_addr + size - 1;
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if (!size || last_addr < phys_addr)
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return NULL;
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/* Page-align mappings */
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offset = phys_addr & (~PAGE_MASK);
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phys_addr -= offset;
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size = PAGE_ALIGN(size + offset);
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if (!ioremap_allowed(phys_addr, size, prot))
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return NULL;
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area = get_vm_area_caller(size, VM_IOREMAP,
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__builtin_return_address(0));
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if (!area)
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return NULL;
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vaddr = (unsigned long)area->addr;
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area->phys_addr = phys_addr;
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if (ioremap_page_range(vaddr, vaddr + size, phys_addr,
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__pgprot(prot))) {
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free_vm_area(area);
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return NULL;
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}
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return (void __iomem *)(vaddr + offset);
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}
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EXPORT_SYMBOL(ioremap_prot);
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void iounmap(volatile void __iomem *addr)
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{
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void *vaddr = (void *)((unsigned long)addr & PAGE_MASK);
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if (!iounmap_allowed(vaddr))
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return;
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if (is_vmalloc_addr(vaddr))
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vunmap(vaddr);
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}
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EXPORT_SYMBOL(iounmap);
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