ACPI: Fix possible alignment issues with GAS 'address' references

Generic Address Structures (GAS) may reside within ACPI tables which
are byte aligned.  This patch copies GAS 'address' references to a local
variable, which will be naturally aligned, to be used going forward.

ACPI Generic Address Structure (GAS) reference:
  ACPI Specification, Revision 4.0, Section 5.2.3.1, "Generic Address
  Structure"

Signed-off-by: Myron Stowe <myron.stowe@redhat.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 24 insertions, 14 deletions

diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index f31c5c5f1b7e..2e285cdbefb1 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -166,17 +166,21 @@ static u32 acpi_osi_handler(acpi_string interface, u32 supported)
         return supported;
 }
 
-static void __init acpi_request_region (struct acpi_generic_address *addr,
+static void __init acpi_request_region (struct acpi_generic_address *gas,
         unsigned int length, char *desc)
 {
-        if (!addr->address || !length)
+        u64 addr;
+
+        /* Handle possible alignment issues */
+        memcpy(&addr, &gas->address, sizeof(addr));
+        if (!addr || !length)
                 return;
 
         /* Resources are never freed */
-        if (addr->space_id == ACPI_ADR_SPACE_SYSTEM_IO)
-                request_region(addr->address, length, desc);
-        else if (addr->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
-                request_mem_region(addr->address, length, desc);
+        if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_IO)
+                request_region(addr, length, desc);
+        else if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
+                request_mem_region(addr, length, desc);
 }
 
 static int __init acpi_reserve_resources(void)
@@ -427,35 +431,41 @@ void __init early_acpi_os_unmap_memory(void __iomem *virt, acpi_size size)
                 __acpi_unmap_table(virt, size);
 }
 
-static int acpi_os_map_generic_address(struct acpi_generic_address *addr)
+static int acpi_os_map_generic_address(struct acpi_generic_address *gas)
 {
+        u64 addr;
         void __iomem *virt;
 
-        if (addr->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY)
+        if (gas->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY)
                 return 0;
 
-        if (!addr->address || !addr->bit_width)
+        /* Handle possible alignment issues */
+        memcpy(&addr, &gas->address, sizeof(addr));
+        if (!addr || !gas->bit_width)
                 return -EINVAL;
 
-        virt = acpi_os_map_memory(addr->address, addr->bit_width / 8);
+        virt = acpi_os_map_memory(addr, gas->bit_width / 8);
         if (!virt)
                 return -EIO;
 
         return 0;
 }
 
-static void acpi_os_unmap_generic_address(struct acpi_generic_address *addr)
+static void acpi_os_unmap_generic_address(struct acpi_generic_address *gas)
 {
+        u64 addr;
         struct acpi_ioremap *map;
 
-        if (addr->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY)
+        if (gas->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY)
                 return;
 
-        if (!addr->address || !addr->bit_width)
+        /* Handle possible alignment issues */
+        memcpy(&addr, &gas->address, sizeof(addr));
+        if (!addr || !gas->bit_width)
                 return;
 
         mutex_lock(&acpi_ioremap_lock);
-        map = acpi_map_lookup(addr->address, addr->bit_width / 8);
+        map = acpi_map_lookup(addr, gas->bit_width / 8);
         if (!map) {
                 mutex_unlock(&acpi_ioremap_lock);
                 return;