[PATCH] ppc64: Fix semantics of __ioremap

[Benjamin Herrenschmidt]

Hi !

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 at kernel.crashing.org>

Index: linux-work/arch/ppc64/kernel/pSeries_setup.c
===================================================================
--- linux-work.orig/arch/ppc64/kernel/pSeries_setup.c	2005-03-10 13:43:01.000000000 +1100
+++ linux-work/arch/ppc64/kernel/pSeries_setup.c	2005-04-04 17:18:34.000000000 +1000
@@ -363,7 +363,7 @@
 		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;
Index: linux-work/arch/ppc64/kernel/maple_setup.c
===================================================================
--- linux-work.orig/arch/ppc64/kernel/maple_setup.c	2005-01-31 14:18:14.000000000 +1100
+++ linux-work/arch/ppc64/kernel/maple_setup.c	2005-04-04 17:18:49.000000000 +1000
@@ -142,7 +142,7 @@
 	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;
Index: linux-work/arch/ppc64/kernel/pci.c
===================================================================
--- linux-work.orig/arch/ppc64/kernel/pci.c	2005-04-03 10:02:55.000000000 +1000
+++ linux-work/arch/ppc64/kernel/pci.c	2005-04-04 17:18:05.000000000 +1000
@@ -547,8 +547,9 @@
 	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 @@
 
 		__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 @@
 	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 @@
 	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;
Index: linux-work/arch/ppc64/mm/init.c
===================================================================
--- linux-work.orig/arch/ppc64/mm/init.c	2005-04-03 10:02:55.000000000 +1000
+++ linux-work/arch/ppc64/mm/init.c	2005-04-04 17:17:01.000000000 +1000
@@ -155,7 +155,8 @@
 		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 @@
 
 	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 @@
 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 @@
 			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 @@
 			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 @@
  * 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)
 {