gpu/drm, x86, PAT: routine to keep identity map in sync

Add a function to check and keep identity maps in sync, when changing
any memory type. One of the follow on patches will also use this
routine.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Eric Anholt <eric@anholt.net>
Cc: Keith Packard <keithp@keithp.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 29 insertions, 17 deletions

diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index aebbf67a79d0..399383c6f614 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -625,6 +625,33 @@ void unmap_devmem(unsigned long pfn, unsigned long size, pgprot_t vma_prot)
 }
 
 /*
+ * Change the memory type for the physial address range in kernel identity
+ * mapping space if that range is a part of identity map.
+ */
+int kernel_map_sync_memtype(u64 base, unsigned long size, unsigned long flags)
+{
+        unsigned long id_sz;
+
+        if (!pat_enabled || base >= __pa(high_memory))
+                return 0;
+
+        id_sz = (__pa(high_memory) < base + size) ?
+                                __pa(high_memory) - base :
+                                size;
+
+        if (ioremap_change_attr((unsigned long)__va(base), id_sz, flags) < 0) {
+                printk(KERN_INFO
+                        "%s:%d ioremap_change_attr failed %s "
+                        "for %Lx-%Lx\n",
+                        current->comm, current->pid,
+                        cattr_name(flags),
+                        base, (unsigned long long)(base + size));
+                return -EINVAL;
+        }
+        return 0;
+}
+
+/*
  * Internal interface to reserve a range of physical memory with prot.
  * Reserved non RAM regions only and after successful reserve_memtype,
  * this func also keeps identity mapping (if any) in sync with this new prot.
@@ -633,7 +660,7 @@ static int reserve_pfn_range(u64 paddr, unsigned long size, pgprot_t *vma_prot,
                                 int strict_prot)
 {
         int is_ram = 0;
-        int id_sz, ret;
+        int ret;
         unsigned long flags;
         unsigned long want_flags = (pgprot_val(*vma_prot) & _PAGE_CACHE_MASK);
 
@@ -670,23 +697,8 @@ static int reserve_pfn_range(u64 paddr, unsigned long size, pgprot_t *vma_prot,
                                      flags);
         }
 
-        /* Need to keep identity mapping in sync */
-        if (paddr >= __pa(high_memory))
-                return 0;
-
-        id_sz = (__pa(high_memory) < paddr + size) ?
-                                __pa(high_memory) - paddr :
-                                size;
-
-        if (ioremap_change_attr((unsigned long)__va(paddr), id_sz, flags) < 0) {
+        if (kernel_map_sync_memtype(paddr, size, flags) < 0) {
                 free_memtype(paddr, paddr + size);
-                printk(KERN_ERR
-                        "%s:%d reserve_pfn_range ioremap_change_attr failed %s "
-                        "for %Lx-%Lx\n",
-                        current->comm, current->pid,
-                        cattr_name(flags),
-                        (unsigned long long)paddr,
-                        (unsigned long long)(paddr + size));
                 return -EINVAL;
         }
         return 0;