From: Christoph Hellwig <hch@xxxxxx> Subject: sparc64: define untagged_addr() 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@xxxxxx Signed-off-by: Christoph Hellwig <hch@xxxxxx> Reviewed-by: Khalid Aziz <khalid.aziz@xxxxxxxxxx> Cc: David Miller <davem@xxxxxxxxxxxxx> Cc: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> Cc: James Hogan <jhogan@xxxxxxxxxx> Cc: Jason Gunthorpe <jgg@xxxxxxxxxxxx> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Cc: Nicholas Piggin <npiggin@xxxxxxxxx> Cc: Paul Burton <paul.burton@xxxxxxxx> Cc: Paul Mackerras <paulus@xxxxxxxxx> Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx> Cc: Rich Felker <dalias@xxxxxxxx> Cc: Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/sparc/include/asm/pgtable_64.h | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) --- a/arch/sparc/include/asm/pgtable_64.h~sparc64-define-untagged_addr +++ a/arch/sparc/include/asm/pgtable_64.h @@ -1078,6 +1078,28 @@ static inline int io_remap_pfn_range(str } #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> _
