| Message ID | 20190611144102.8848-9-hch@lst.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [01/16] mm: use untagged_addr() for get_user_pages_fast addresses | expand |
On 6/11/19 8:40 AM, Christoph Hellwig wrote: > Add a helper to untag a user pointer. This is needed for ADI support > in get_user_pages_fast. > > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > arch/sparc/include/asm/pgtable_64.h | 22 ++++++++++++++++++++++ > 1 file changed, 22 insertions(+) Looks good to me. Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com> > > diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h > index f0dcf991d27f..1904782dcd39 100644 > --- a/arch/sparc/include/asm/pgtable_64.h > +++ b/arch/sparc/include/asm/pgtable_64.h > @@ -1076,6 +1076,28 @@ 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> > >
diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h index f0dcf991d27f..1904782dcd39 100644 --- a/arch/sparc/include/asm/pgtable_64.h +++ b/arch/sparc/include/asm/pgtable_64.h @@ -1076,6 +1076,28 @@ 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>
Add a helper to untag a user pointer. This is needed for ADI support in get_user_pages_fast. Signed-off-by: Christoph Hellwig <hch@lst.de> --- arch/sparc/include/asm/pgtable_64.h | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+)