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authorLogan Gunthorpe <logang@deltatee.com>2020-04-10 14:33:39 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-04-10 15:36:21 -0700
commita50d8d98a87f33efa07adfa20747e13a93839a4b (patch)
tree578950351241f47660415616fe1005f7a7950ae0
parentbfeb022f8fe4c5afdcfd7a3d868fac9765f9bcad (diff)
downloadlinux-stericsson-a50d8d98a87f33efa07adfa20747e13a93839a4b.tar.gz
mm/memremap: set caching mode for PCI P2PDMA memory to WC
PCI BAR IO memory should never be mapped as WB, however prior to this the PAT bits were set WB and it was typically overridden by MTRR registers set by the firmware. Set PCI P2PDMA memory to be UC as this is what it currently, typically, ends up being mapped as on x86 after the MTRR registers override the cache setting. Future use-cases may need to generalize this by adding flags to select the caching type, as some P2PDMA cases may not want UC. However, those use-cases are not upstream yet and this can be changed when they arrive. Signed-off-by: Logan Gunthorpe <logang@deltatee.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Andy Lutomirski <luto@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: Eric Badger <ebadger@gigaio.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@suse.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will@kernel.org> Link: http://lkml.kernel.org/r/20200306170846.9333-8-logang@deltatee.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/memremap.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/mm/memremap.c b/mm/memremap.c
index bc167cde3237..03e38b7a38f1 100644
--- a/mm/memremap.c
+++ b/mm/memremap.c
@@ -217,7 +217,10 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid)
}
break;
case MEMORY_DEVICE_DEVDAX:
+ need_devmap_managed = false;
+ break;
case MEMORY_DEVICE_PCI_P2PDMA:
+ params.pgprot = pgprot_noncached(params.pgprot);
need_devmap_managed = false;
break;
default: