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1fbaf8fc12
Add a helper that calls remap_pfn_range for an struct io_mapping, relying on the pgprot pre-validation done when creating the mapping instead of doing it at runtime. Link: https://lkml.kernel.org/r/20210326055505.1424432-3-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
30 lines
993 B
C
30 lines
993 B
C
// SPDX-License-Identifier: GPL-2.0-only
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#include <linux/mm.h>
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#include <linux/io-mapping.h>
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/**
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* io_mapping_map_user - remap an I/O mapping to userspace
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* @iomap: the source io_mapping
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* @vma: user vma to map to
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* @addr: target user address to start at
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* @pfn: physical address of kernel memory
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* @size: size of map area
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*
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* Note: this is only safe if the mm semaphore is held when called.
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*/
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int io_mapping_map_user(struct io_mapping *iomap, struct vm_area_struct *vma,
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unsigned long addr, unsigned long pfn, unsigned long size)
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{
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vm_flags_t expected_flags = VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
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if (WARN_ON_ONCE((vma->vm_flags & expected_flags) != expected_flags))
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return -EINVAL;
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/* We rely on prevalidation of the io-mapping to skip track_pfn(). */
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return remap_pfn_range_notrack(vma, addr, pfn, size,
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__pgprot((pgprot_val(iomap->prot) & _PAGE_CACHE_MASK) |
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(pgprot_val(vma->vm_page_prot) & ~_PAGE_CACHE_MASK)));
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}
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EXPORT_SYMBOL_GPL(io_mapping_map_user);
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