[PATCH] ppc64: Fix semantics of __ioremap

This patch fixes ppc64 __ioremap() so that it stops adding implicitely
_PAGE_GUARDED when the cache is not writeback, and instead, let the callers
provide the flag they want here.  This allows things like framebuffers to
explicitely request a non-cacheable and non-guarded mapping which is more
efficient for that type of memory without side effects.  The patch also
fixes all current callers to add _PAGE_GUARDED except btext, which is fine
without it.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 7 insertions, 5 deletions

diff --git a/arch/ppc64/kernel/pci.c b/arch/ppc64/kernel/pci.c
index fdd8f7869a6..be3cc387c1e 100644
--- a/arch/ppc64/kernel/pci.c
+++ b/arch/ppc64/kernel/pci.c
@@ -547,8 +547,9 @@ static void __devinit pci_process_ISA_OF_ranges(struct device_node *isa_node,
         if (range == NULL || (rlen < sizeof(struct isa_range))) {
                 printk(KERN_ERR "no ISA ranges or unexpected isa range size,"
                        "mapping 64k\n");
-                __ioremap_explicit(phb_io_base_phys, (unsigned long)phb_io_base_virt, 
-                                   0x10000, _PAGE_NO_CACHE);
+                __ioremap_explicit(phb_io_base_phys,
+                                   (unsigned long)phb_io_base_virt,
+                                   0x10000, _PAGE_NO_CACHE | _PAGE_GUARDED);
                 return; 
         }
         
@@ -576,7 +577,7 @@ static void __devinit pci_process_ISA_OF_ranges(struct device_node *isa_node,
 
                 __ioremap_explicit(phb_io_base_phys, 
                                    (unsigned long) phb_io_base_virt, 
-                                   size, _PAGE_NO_CACHE);
+                                   size, _PAGE_NO_CACHE | _PAGE_GUARDED);
         }
 }
 
@@ -692,7 +693,7 @@ void __devinit pci_setup_phb_io_dynamic(struct pci_controller *hose,
         struct resource *res;
 
         hose->io_base_virt = __ioremap(hose->io_base_phys, size,
-                                        _PAGE_NO_CACHE);
+                                        _PAGE_NO_CACHE | _PAGE_GUARDED);
         DBG("phb%d io_base_phys 0x%lx io_base_virt 0x%lx\n",
                 hose->global_number, hose->io_base_phys,
                 (unsigned long) hose->io_base_virt);
@@ -780,7 +781,8 @@ int remap_bus_range(struct pci_bus *bus)
         if (get_bus_io_range(bus, &start_phys, &start_virt, &size))
                 return 1;
         printk("mapping IO %lx -> %lx, size: %lx\n", start_phys, start_virt, size);
-        if (__ioremap_explicit(start_phys, start_virt, size, _PAGE_NO_CACHE))
+        if (__ioremap_explicit(start_phys, start_virt, size,
+                               _PAGE_NO_CACHE | _PAGE_GUARDED))
                 return 1;
 
         return 0;