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)

2 files changed, 20 insertions, 0 deletions

diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h
index de25aad07853..d34bd370074b 100644
--- a/arch/x86/include/asm/io.h
+++ b/arch/x86/include/asm/io.h
@@ -351,4 +351,10 @@ extern void arch_phys_wc_del(int handle);
 #define arch_phys_wc_add arch_phys_wc_add
 #endif
 
+#ifdef CONFIG_X86_PAT
+extern int arch_io_reserve_memtype_wc(resource_size_t start, resource_size_t size);
+extern void arch_io_free_memtype_wc(resource_size_t start, resource_size_t size);
+#define arch_io_reserve_memtype_wc arch_io_reserve_memtype_wc
+#endif
+
 #endif /* _ASM_X86_IO_H */
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 170cc4ff057b..83e701f160a9 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -730,6 +730,20 @@ void io_free_memtype(resource_size_t start, resource_size_t end)
 	free_memtype(start, end);
 }
 
+int arch_io_reserve_memtype_wc(resource_size_t start, resource_size_t size)
+{
+	enum page_cache_mode type = _PAGE_CACHE_MODE_WC;
+
+	return io_reserve_memtype(start, start + size, &type);
+}
+EXPORT_SYMBOL(arch_io_reserve_memtype_wc);
+
+void arch_io_free_memtype_wc(resource_size_t start, resource_size_t size)
+{
+	io_free_memtype(start, start + size);
+}
+EXPORT_SYMBOL(arch_io_free_memtype_wc);
+
 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
 				unsigned long size, pgprot_t vma_prot)
 {