[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>

4 files changed, 18 insertions, 16 deletions

diff --git a/arch/ppc64/kernel/maple_setup.c b/arch/ppc64/kernel/maple_setup.c
index 1db6ea0f336..8cf95a27178 100644
--- a/arch/ppc64/kernel/maple_setup.c
+++ b/arch/ppc64/kernel/maple_setup.c
@@ -142,7 +142,7 @@ static void __init maple_init_early(void)
         if (physport) {
                 void *comport;
                 /* Map the uart for udbg. */
-                comport = (void *)__ioremap(physport, 16, _PAGE_NO_CACHE);
+                comport = (void *)ioremap(physport, 16);
                 udbg_init_uart(comport, default_speed);
 
                 ppc_md.udbg_putc = udbg_putc;
diff --git a/arch/ppc64/kernel/pSeries_setup.c b/arch/ppc64/kernel/pSeries_setup.c
index 06536de5125..6c0d1d58a55 100644
--- a/arch/ppc64/kernel/pSeries_setup.c
+++ b/arch/ppc64/kernel/pSeries_setup.c
@@ -363,7 +363,7 @@ static void __init pSeries_init_early(void)
                 find_udbg_vterm();
         else if (physport) {
                 /* Map the uart for udbg. */
-                comport = (void *)__ioremap(physport, 16, _PAGE_NO_CACHE);
+                comport = (void *)ioremap(physport, 16);
                 udbg_init_uart(comport, default_speed);
 
                 ppc_md.udbg_putc = udbg_putc;
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;
diff --git a/arch/ppc64/mm/init.c b/arch/ppc64/mm/init.c
index 23813d03e1c..a7149b9fc35 100644
--- a/arch/ppc64/mm/init.c
+++ b/arch/ppc64/mm/init.c
@@ -155,7 +155,8 @@ static void map_io_page(unsigned long ea, unsigned long pa, int flags)
                 ptep = pte_alloc_kernel(&ioremap_mm, pmdp, ea);
 
                 pa = abs_to_phys(pa);
-                set_pte_at(&ioremap_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT, __pgprot(flags)));
+                set_pte_at(&ioremap_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT,
+                                                          __pgprot(flags)));
                 spin_unlock(&ioremap_mm.page_table_lock);
         } else {
                 unsigned long va, vpn, hash, hpteg;
@@ -191,12 +192,9 @@ static void __iomem * __ioremap_com(unsigned long addr, unsigned long pa,
 
         if ((flags & _PAGE_PRESENT) == 0)
                 flags |= pgprot_val(PAGE_KERNEL);
-        if (flags & (_PAGE_NO_CACHE | _PAGE_WRITETHRU))
-                flags |= _PAGE_GUARDED;
 
-        for (i = 0; i < size; i += PAGE_SIZE) {
+        for (i = 0; i < size; i += PAGE_SIZE)
                 map_io_page(ea+i, pa+i, flags);
-        }
 
         return (void __iomem *) (ea + (addr & ~PAGE_MASK));
 }
@@ -205,7 +203,7 @@ static void __iomem * __ioremap_com(unsigned long addr, unsigned long pa,
 void __iomem *
 ioremap(unsigned long addr, unsigned long size)
 {
-        return __ioremap(addr, size, _PAGE_NO_CACHE);
+        return __ioremap(addr, size, _PAGE_NO_CACHE | _PAGE_GUARDED);
 }
 
 void __iomem *
@@ -272,7 +270,8 @@ int __ioremap_explicit(unsigned long pa, unsigned long ea,
                         return 1;
                 }
                 if (ea != (unsigned long) area->addr) {
-                        printk(KERN_ERR "unexpected addr return from im_get_area\n");
+                        printk(KERN_ERR "unexpected addr return from "
+                               "im_get_area\n");
                         return 1;
                 }
         }
@@ -315,7 +314,8 @@ static void unmap_im_area_pte(pmd_t *pmd, unsigned long address,
                         continue;
                 if (pte_present(page))
                         continue;
-                printk(KERN_CRIT "Whee.. Swapped out page in kernel page table\n");
+                printk(KERN_CRIT "Whee.. Swapped out page in kernel page"
+                       " table\n");
         } while (address < end);
 }
 
@@ -352,7 +352,7 @@ static void unmap_im_area_pmd(pgd_t *dir, unsigned long address,
  * Access to IO memory should be serialized by driver.
  * This code is modeled after vmalloc code - unmap_vm_area()
  *
- * XXX  what about calls before mem_init_done (ie python_countermeasures())     
+ * XXX  what about calls before mem_init_done (ie python_countermeasures())
  */
 void iounmap(volatile void __iomem *token)
 {