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authorLinus Torvalds <torvalds@linux-foundation.org>2016-10-28 09:36:07 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-10-28 09:36:07 -0700
commitbdb520845b5700284f34437fadb920000c306466 (patch)
tree352847387131dd3fed32b8b83b96fb00a99bf548 /include
parente0f3e6a7ccc002be056b6a21768fceee0d44941e (diff)
parent7cf321d118a825c1541b43ca45294126fd474efa (diff)
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Merge tag 'drm-x86-pat-regression-fix' of git://people.freedesktop.org/~airlied/linux
Pull drm x86/pat regression fixes from Dave Airlie: "This is a standalone pull request for the fix for a regression introduced in -rc1 by a change to vm_insert_mixed to start using the PAT range tracking to validate page protections. With this fix in place, all the VRAM mappings for GPU drivers ended up at UC instead of WC. There are probably better ways to fix this long term, but nothing I'd considered for -fixes that wouldn't need more settling in time. So I've just created a new arch API that the drivers can reserve all their VRAM aperture ranges as WC" * tag 'drm-x86-pat-regression-fix' of git://people.freedesktop.org/~airlied/linux: drm/drivers: add support for using the arch wc mapping API. x86/io: add interface to reserve io memtype for a resource range. (v1.1)
Diffstat (limited to 'include')
-rw-r--r--include/linux/io.h22
1 files changed, 22 insertions, 0 deletions
diff --git a/include/linux/io.h b/include/linux/io.h
index e2c8419278c1..82ef36eac8a1 100644
--- a/include/linux/io.h
+++ b/include/linux/io.h
@@ -141,4 +141,26 @@ enum {
void *memremap(resource_size_t offset, size_t size, unsigned long flags);
void memunmap(void *addr);
+/*
+ * On x86 PAT systems we have memory tracking that keeps track of
+ * the allowed mappings on memory ranges. This tracking works for
+ * all the in-kernel mapping APIs (ioremap*), but where the user
+ * wishes to map a range from a physical device into user memory
+ * the tracking won't be updated. This API is to be used by
+ * drivers which remap physical device pages into userspace,
+ * and wants to make sure they are mapped WC and not UC.
+ */
+#ifndef arch_io_reserve_memtype_wc
+static inline int arch_io_reserve_memtype_wc(resource_size_t base,
+ resource_size_t size)
+{
+ return 0;
+}
+
+static inline void arch_io_free_memtype_wc(resource_size_t base,
+ resource_size_t size)
+{
+}
+#endif
+
#endif /* _LINUX_IO_H */