Pull rework-memory-attribute-aliasing into release branch

3 files changed, 139 insertions, 61 deletions

diff --git a/arch/ia64/kernel/efi.c b/arch/ia64/kernel/efi.c
index 12cfedc..c33d0ba 100644
--- a/arch/ia64/kernel/efi.c
+++ b/arch/ia64/kernel/efi.c
@@ -8,6 +8,8 @@
  * Copyright (C) 1999-2003 Hewlett-Packard Co.
  *	David Mosberger-Tang <davidm@hpl.hp.com>
  *	Stephane Eranian <eranian@hpl.hp.com>
+ * (c) Copyright 2006 Hewlett-Packard Development Company, L.P.
+ *	Bjorn Helgaas <bjorn.helgaas@hp.com>
  *
  * All EFI Runtime Services are not implemented yet as EFI only
  * supports physical mode addressing on SoftSDV. This is to be fixed
@@ -622,28 +624,20 @@ efi_get_iobase (void)
 	return 0;
 }
 
-static efi_memory_desc_t *
-efi_memory_descriptor (unsigned long phys_addr)
+static struct kern_memdesc *
+kern_memory_descriptor (unsigned long phys_addr)
 {
-	void *efi_map_start, *efi_map_end, *p;
-	efi_memory_desc_t *md;
-	u64 efi_desc_size;
-
-	efi_map_start = __va(ia64_boot_param->efi_memmap);
-	efi_map_end   = efi_map_start + ia64_boot_param->efi_memmap_size;
-	efi_desc_size = ia64_boot_param->efi_memdesc_size;
+	struct kern_memdesc *md;
 
-	for (p = efi_map_start; p < efi_map_end; p += efi_desc_size) {
-		md = p;
-
-		if (phys_addr - md->phys_addr < (md->num_pages << EFI_PAGE_SHIFT))
+	for (md = kern_memmap; md->start != ~0UL; md++) {
+		if (phys_addr - md->start < (md->num_pages << EFI_PAGE_SHIFT))
 			 return md;
 	}
 	return 0;
 }
 
-static int
-efi_memmap_has_mmio (void)
+static efi_memory_desc_t *
+efi_memory_descriptor (unsigned long phys_addr)
 {
 	void *efi_map_start, *efi_map_end, *p;
 	efi_memory_desc_t *md;
@@ -656,8 +650,8 @@ efi_memmap_has_mmio (void)
 	for (p = efi_map_start; p < efi_map_end; p += efi_desc_size) {
 		md = p;
 
-		if (md->type == EFI_MEMORY_MAPPED_IO)
-			return 1;
+		if (phys_addr - md->phys_addr < (md->num_pages << EFI_PAGE_SHIFT))
+			 return md;
 	}
 	return 0;
 }
@@ -683,71 +677,125 @@ efi_mem_attributes (unsigned long phys_addr)
 }
 EXPORT_SYMBOL(efi_mem_attributes);
 
-/*
- * Determines whether the memory at phys_addr supports the desired
- * attribute (WB, UC, etc).  If this returns 1, the caller can safely
- * access size bytes at phys_addr with the specified attribute.
- */
-int
-efi_mem_attribute_range (unsigned long phys_addr, unsigned long size, u64 attr)
+u64
+efi_mem_attribute (unsigned long phys_addr, unsigned long size)
 {
 	unsigned long end = phys_addr + size;
 	efi_memory_desc_t *md = efi_memory_descriptor(phys_addr);
+	u64 attr;
+
+	if (!md)
+		return 0;
+
+	/*
+	 * EFI_MEMORY_RUNTIME is not a memory attribute; it just tells
+	 * the kernel that firmware needs this region mapped.
+	 */
+	attr = md->attribute & ~EFI_MEMORY_RUNTIME;
+	do {
+		unsigned long md_end = efi_md_end(md);
+
+		if (end <= md_end)
+			return attr;
+
+		md = efi_memory_descriptor(md_end);
+		if (!md || (md->attribute & ~EFI_MEMORY_RUNTIME) != attr)
+			return 0;
+	} while (md);
+	return 0;
+}
+
+u64
+kern_mem_attribute (unsigned long phys_addr, unsigned long size)
+{
+	unsigned long end = phys_addr + size;
+	struct kern_memdesc *md;
+	u64 attr;
 
 	/*
-	 * Some firmware doesn't report MMIO regions in the EFI memory
-	 * map.  The Intel BigSur (a.k.a. HP i2000) has this problem.
-	 * On those platforms, we have to assume UC is valid everywhere.
+	 * This is a hack for ioremap calls before we set up kern_memmap.
+	 * Maybe we should do efi_memmap_init() earlier instead.
 	 */
-	if (!md || (md->attribute & attr) != attr) {
-		if (attr == EFI_MEMORY_UC && !efi_memmap_has_mmio())
-			return 1;
+	if (!kern_memmap) {
+		attr = efi_mem_attribute(phys_addr, size);
+		if (attr & EFI_MEMORY_WB)
+			return EFI_MEMORY_WB;
 		return 0;
 	}
 
+	md = kern_memory_descriptor(phys_addr);
+	if (!md)
+		return 0;
+
+	attr = md->attribute;
 	do {
-		unsigned long md_end = efi_md_end(md);
+		unsigned long md_end = kmd_end(md);
 
 		if (end <= md_end)
-			return 1;
+			return attr;
 
-		md = efi_memory_descriptor(md_end);
-		if (!md || (md->attribute & attr) != attr)
+		md = kern_memory_descriptor(md_end);
+		if (!md || md->attribute != attr)
 			return 0;
 	} while (md);
 	return 0;
 }
+EXPORT_SYMBOL(kern_mem_attribute);
 
-/*
- * For /dev/mem, we only allow read & write system calls to access
- * write-back memory, because read & write don't allow the user to
- * control access size.
- */
 int
 valid_phys_addr_range (unsigned long phys_addr, unsigned long size)
 {
-	return efi_mem_attribute_range(phys_addr, size, EFI_MEMORY_WB);
+	u64 attr;
+
+	/*
+	 * /dev/mem reads and writes use copy_to_user(), which implicitly
+	 * uses a granule-sized kernel identity mapping.  It's really
+	 * only safe to do this for regions in kern_memmap.  For more
+	 * details, see Documentation/ia64/aliasing.txt.
+	 */
+	attr = kern_mem_attribute(phys_addr, size);
+	if (attr & EFI_MEMORY_WB || attr & EFI_MEMORY_UC)
+		return 1;
+	return 0;
 }
 
-/*
- * We allow mmap of anything in the EFI memory map that supports
- * either write-back or uncacheable access.  For uncacheable regions,
- * the supported access sizes are system-dependent, and the user is
- * responsible for using the correct size.
- *
- * Note that this doesn't currently allow access to hot-added memory,
- * because that doesn't appear in the boot-time EFI memory map.
- */
 int
 valid_mmap_phys_addr_range (unsigned long phys_addr, unsigned long size)
 {
-	if (efi_mem_attribute_range(phys_addr, size, EFI_MEMORY_WB))
-		return 1;
+	/*
+	 * MMIO regions are often missing from the EFI memory map.
+	 * We must allow mmap of them for programs like X, so we
+	 * currently can't do any useful validation.
+	 */
+	return 1;
+}
 
-	if (efi_mem_attribute_range(phys_addr, size, EFI_MEMORY_UC))
-		return 1;
+pgprot_t
+phys_mem_access_prot(struct file *file, unsigned long pfn, unsigned long size,
+		     pgprot_t vma_prot)
+{
+	unsigned long phys_addr = pfn << PAGE_SHIFT;
+	u64 attr;
 
-	return 0;
+	/*
+	 * For /dev/mem mmap, we use user mappings, but if the region is
+	 * in kern_memmap (and hence may be covered by a kernel mapping),
+	 * we must use the same attribute as the kernel mapping.
+	 */
+	attr = kern_mem_attribute(phys_addr, size);
+	if (attr & EFI_MEMORY_WB)
+		return pgprot_cacheable(vma_prot);
+	else if (attr & EFI_MEMORY_UC)
+		return pgprot_noncached(vma_prot);
+
+	/*
+	 * Some chipsets don't support UC access to memory.  If
+	 * WB is supported, we prefer that.
+	 */
+	if (efi_mem_attribute(phys_addr, size) & EFI_MEMORY_WB)
+		return pgprot_cacheable(vma_prot);
+
+	return pgprot_noncached(vma_prot);
 }
 
 int __init
diff --git a/arch/ia64/mm/ioremap.c b/arch/ia64/mm/ioremap.c
index 643ccc6..07bd02b 100644
--- a/arch/ia64/mm/ioremap.c
+++ b/arch/ia64/mm/ioremap.c
@@ -11,6 +11,7 @@
 #include <linux/module.h>
 #include <linux/efi.h>
 #include <asm/io.h>
+#include <asm/meminit.h>
 
 static inline void __iomem *
 __ioremap (unsigned long offset, unsigned long size)
@@ -21,16 +22,29 @@ __ioremap (unsigned long offset, unsigned long size)
 void __iomem *
 ioremap (unsigned long offset, unsigned long size)
 {
-	if (efi_mem_attribute_range(offset, size, EFI_MEMORY_WB))
-		return phys_to_virt(offset);
+	u64 attr;
+	unsigned long gran_base, gran_size;
 
-	if (efi_mem_attribute_range(offset, size, EFI_MEMORY_UC))
+	/*
+	 * For things in kern_memmap, we must use the same attribute
+	 * as the rest of the kernel.  For more details, see
+	 * Documentation/ia64/aliasing.txt.
+	 */
+	attr = kern_mem_attribute(offset, size);
+	if (attr & EFI_MEMORY_WB)
+		return phys_to_virt(offset);
+	else if (attr & EFI_MEMORY_UC)
 		return __ioremap(offset, size);
 
 	/*
-	 * Someday this should check ACPI resources so we
-	 * can do the right thing for hot-plugged regions.
+	 * Some chipsets don't support UC access to memory.  If
+	 * WB is supported for the whole granule, we prefer that.
 	 */
+	gran_base = GRANULEROUNDDOWN(offset);
+	gran_size = GRANULEROUNDUP(offset + size) - gran_base;
+	if (efi_mem_attribute(gran_base, gran_size) & EFI_MEMORY_WB)
+		return phys_to_virt(offset);
+
 	return __ioremap(offset, size);
 }
 EXPORT_SYMBOL(ioremap);
@@ -38,6 +52,9 @@ EXPORT_SYMBOL(ioremap);
 void __iomem *
 ioremap_nocache (unsigned long offset, unsigned long size)
 {
+	if (kern_mem_attribute(offset, size) & EFI_MEMORY_WB)
+		return 0;
+
 	return __ioremap(offset, size);
 }
 EXPORT_SYMBOL(ioremap_nocache);
diff --git a/arch/ia64/pci/pci.c b/arch/ia64/pci/pci.c
index ab829a2..30d148f 100644
--- a/arch/ia64/pci/pci.c
+++ b/arch/ia64/pci/pci.c
@@ -645,18 +645,31 @@ char *ia64_pci_get_legacy_mem(struct pci_bus *bus)
 int
 pci_mmap_legacy_page_range(struct pci_bus *bus, struct vm_area_struct *vma)
 {
+	unsigned long size = vma->vm_end - vma->vm_start;
+	pgprot_t prot;
 	char *addr;
 
+	/*
+	 * Avoid attribute aliasing.  See Documentation/ia64/aliasing.txt
+	 * for more details.
+	 */
+	if (!valid_mmap_phys_addr_range(vma->vm_pgoff << PAGE_SHIFT, size))
+		return -EINVAL;
+	prot = phys_mem_access_prot(NULL, vma->vm_pgoff, size,
+				    vma->vm_page_prot);
+	if (pgprot_val(prot) != pgprot_val(pgprot_noncached(vma->vm_page_prot)))
+		return -EINVAL;
+
 	addr = pci_get_legacy_mem(bus);
 	if (IS_ERR(addr))
 		return PTR_ERR(addr);
 
 	vma->vm_pgoff += (unsigned long)addr >> PAGE_SHIFT;
-	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+	vma->vm_page_prot = prot;
 	vma->vm_flags |= (VM_SHM | VM_RESERVED | VM_IO);
 
 	if (remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
-			    vma->vm_end - vma->vm_start, vma->vm_page_prot))
+			    size, vma->vm_page_prot))
 		return -EAGAIN;
 
 	return 0;