ACPICA: Hardware: Enhance acpi_hw_validate_register() with access_width/bit_offset...

ACPICA commit 997a90f810a4cb78604ef2e187611a181b498286

This patch enhances acpi_hw_validate_register() to sanitize register
accesses with awareness of access_width and bit_offset. Lv Zheng.

Link: https://github.com/acpica/acpica/commit/997a90f8
Link: https://bugs.acpica.org/show_bug.cgi?id=1240
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/acpi/acpica/hwregs.c b/drivers/acpi/acpica/hwregs.c
index 5ba0498..035fb52 100644 (file)
--- a/drivers/acpi/acpica/hwregs.c
+++ b/drivers/acpi/acpica/hwregs.c
@@ -83,6 +83,8 @@ acpi_status
 acpi_hw_validate_register(struct acpi_generic_address *reg,
                          u8 max_bit_width, u64 *address)
 {
+       u8 bit_width;
+       u8 access_width;
 
        /* Must have a valid pointer to a GAS structure */
 
@@ -109,23 +111,26 @@ acpi_hw_validate_register(struct acpi_generic_address *reg,
                return (AE_SUPPORT);
        }
 
-       /* Validate the bit_width */
+       /* Validate the access_width */
 
-       if ((reg->bit_width != 8) &&
-           (reg->bit_width != 16) &&
-           (reg->bit_width != 32) && (reg->bit_width != max_bit_width)) {
+       if (reg->access_width > 4) {
                ACPI_ERROR((AE_INFO,
-                           "Unsupported register bit width: 0x%X",
-                           reg->bit_width));
+                           "Unsupported register access width: 0x%X",
+                           reg->access_width));
                return (AE_SUPPORT);
        }
 
-       /* Validate the bit_offset. Just a warning for now. */
+       /* Validate the bit_width, convert access_width into number of bits */
 
-       if (reg->bit_offset != 0) {
+       access_width = reg->access_width ? reg->access_width : 1;
+       access_width = 1 << (access_width + 2);
+       bit_width =
+           ACPI_ROUND_UP(reg->bit_offset + reg->bit_width, access_width);
+       if (max_bit_width < bit_width) {
                ACPI_WARNING((AE_INFO,
-                             "Unsupported register bit offset: 0x%X",
-                             reg->bit_offset));
+                             "Requested bit width 0x%X is smaller than register bit width 0x%X",
+                             max_bit_width, bit_width));
+               return (AE_SUPPORT);
        }
 
        return (AE_OK);