Pull rework-memory-attribute-aliasing into release branch

1 files changed, 102 insertions, 54 deletions

diff --git a/arch/ia64/kernel/efi.c b/arch/ia64/kernel/efi.c
index 12cfedce73b1..c33d0ba7e300 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