acpi_table: Fix coverity defect in acpi_write_spcr

Fix "Integer handling issues  (SIGN_EXTENSION)" in newly added code:
Cast serial_info.reg_offset to u64 to prevent an integer overflow when
shifted too many bits to the left. Currently this never happens as the
shift is supposed to be less than 4.

Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-by: Moritz Fischer <moritzf@google.com>

diff --git a/lib/acpi/acpi_table.c b/lib/acpi/acpi_table.c
index 6473d95c1028d6e92588be8fc57eb50861cc36e1..b9e12228fda3afffff71e819e086a67e3b630de3 100644 (file)
--- a/lib/acpi/acpi_table.c
+++ b/lib/acpi/acpi_table.c
@@ -420,7 +420,7 @@ int acpi_write_dbg2_pci_uart(struct acpi_ctx *ctx, struct udevice *dev,
 static int acpi_write_spcr(struct acpi_ctx *ctx, const struct acpi_writer *entry)
 {
        struct serial_device_info serial_info = {0};
-       ulong serial_address, serial_offset;
+       u64 serial_address, serial_offset;
        struct acpi_table_header *header;
        struct acpi_spcr *spcr;
        struct udevice *dev;
@@ -473,7 +473,7 @@ static int acpi_write_spcr(struct acpi_ctx *ctx, const struct acpi_writer *entry
        }
 
        serial_width = serial_info.reg_width * 8;
-       serial_offset = serial_info.reg_offset << serial_info.reg_shift;
+       serial_offset = ((u64)serial_info.reg_offset) << serial_info.reg_shift;
        serial_address = serial_info.addr + serial_offset;
 
        /* Encode register access size */