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sparc64: define untagged_addr()

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Add a helper to untag a user pointer.  This is needed for ADI support
in get_user_pages_fast.

Link: http://lkml.kernel.org/r/20190625143715.1689-9-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com>
Cc: David Miller <davem@davemloft.net>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Christoph Hellwig 2019-07-11 20:57:07 -07:00 committed by Linus Torvalds
parent d85507901f
commit 5875509d2f
1 changed files with 22 additions and 0 deletions
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22
arch/sparc/include/asm/pgtable_64.h
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@ -1078,6 +1078,28 @@ static inline int io_remap_pfn_range(struct vm_area_struct *vma,
}
#define io_remap_pfn_range io_remap_pfn_range
static inline unsigned long untagged_addr(unsigned long start)
{
if (adi_capable()) {
long addr = start;
/* If userspace has passed a versioned address, kernel
* will not find it in the VMAs since it does not store
* the version tags in the list of VMAs. Storing version
* tags in list of VMAs is impractical since they can be
* changed any time from userspace without dropping into
* kernel. Any address search in VMAs will be done with
* non-versioned addresses. Ensure the ADI version bits
* are dropped here by sign extending the last bit before
* ADI bits. IOMMU does not implement version tags.
*/
return (addr << (long)adi_nbits()) >> (long)adi_nbits();
}
return start;
}
#define untagged_addr untagged_addr
#include <asm/tlbflush.h>
#include <asm-generic/pgtable.h>