x86, ioremap: Fix incorrect physical address handling in PAE mode

Current x86 ioremap() doesn't handle physical address higher than
32-bit properly in X86_32 PAE mode. When physical address higher than
32-bit is passed to ioremap(), higher 32-bits in physical address is
cleared wrongly. Due to this bug, ioremap() can map wrong address to
linear address space.

In my case, 64-bit MMIO region was assigned to a PCI device (ioat
device) on my system. Because of the ioremap()'s bug, wrong physical
address (instead of MMIO region) was mapped to linear address space.
Because of this, loading ioatdma driver caused unexpected behavior
(kernel panic, kernel hangup, ...).

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
LKML-Reference: <4C1AE680.7090408@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 5 insertions, 7 deletions

diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 12e4d2d3c110..754cb4cbce66 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -62,8 +62,8 @@ int ioremap_change_attr(unsigned long vaddr, unsigned long size,
 static void __iomem *__ioremap_caller(resource_size_t phys_addr,
                 unsigned long size, unsigned long prot_val, void *caller)
 {
-        unsigned long pfn, offset, vaddr;
-        resource_size_t last_addr;
+        unsigned long offset, vaddr;
+        resource_size_t pfn, last_pfn, last_addr;
         const resource_size_t unaligned_phys_addr = phys_addr;
         const unsigned long unaligned_size = size;
         struct vm_struct *area;
@@ -100,10 +100,8 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
         /*
          * Don't allow anybody to remap normal RAM that we're using..
          */
-        for (pfn = phys_addr >> PAGE_SHIFT;
-                                (pfn << PAGE_SHIFT) < (last_addr & PAGE_MASK);
-                                pfn++) {
-
+        last_pfn = last_addr >> PAGE_SHIFT;
+        for (pfn = phys_addr >> PAGE_SHIFT; pfn < last_pfn; pfn++) {
                 int is_ram = page_is_ram(pfn);
 
                 if (is_ram && pfn_valid(pfn) && !PageReserved(pfn_to_page(pfn)))
@@ -115,7 +113,7 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
          * Mappings have to be page-aligned
          */
         offset = phys_addr & ~PAGE_MASK;
-        phys_addr &= PAGE_MASK;
+        phys_addr &= PHYSICAL_PAGE_MASK;
         size = PAGE_ALIGN(last_addr+1) - phys_addr;
 
         retval = reserve_memtype(phys_addr, (u64)phys_addr + size,