[PATCH -v2 1/4] ACPI: Fix possible alignment issues with GAS 'address' references

Myron Stowe
2011-11-07T23:23:27Z

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>
---

drivers/acpi/osl.c | 38 ++++++++++++++++++++++++--------------
1 files changed, 24 insertions(+), 14 deletions(-)

diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index f31c5c5..2e285cd 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;