[PATCH 08/16] sparc64: define untagged_addr()
From: Christoph Hellwig <hch@lst.de>
Date: 2019-06-11 14:41:45
Also in:
linux-mips, linux-mm, linux-sh, lkml, sparclinux
Subsystem:
sparc + ultrasparc (sparc/sparc64), the rest · Maintainers:
"David S. Miller", Andreas Larsson, Linus Torvalds
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(+)
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>
--
2.20.1