From mboxrd@z Thu Jan 1 00:00:00 1970 From: Khalid Aziz Date: Tue, 11 Jun 2019 19:23:17 +0000 Subject: Re: [PATCH 08/16] sparc64: define untagged_addr() Message-Id: <13f72660-8f7b-a437-e449-6b4267de9c0c@oracle.com> List-Id: References: <20190611144102.8848-1-hch@lst.de> <20190611144102.8848-9-hch@lst.de> In-Reply-To: <20190611144102.8848-9-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Christoph Hellwig , Linus Torvalds , Paul Burton , James Hogan , Yoshinori Sato , Rich Felker , "David S. Miller" Cc: Nicholas Piggin , Andrey Konovalov , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , linux-mips@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org, x86@kernel.org, linux-kernel@vger.kernel.org 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 > --- > arch/sparc/include/asm/pgtable_64.h | 22 ++++++++++++++++++++++ > 1 file changed, 22 insertions(+) Looks good to me. Reviewed-by: Khalid Aziz > > 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 > #include > >