ACPI: CPPC: Fix up I/O port access in cpc_read()

The code as currently implemented does not work on big endian systems,
so fix it up.

Fixes: a2c8f92bea5f ("ACPI: CPPC: Implement support for SystemIO registers")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Suggested-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/linux-acpi/20220111092928.GA24968@kili/
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Huang Rui <ray.huang@amd.com>

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index a9d2de4..5bc5532 100644 (file)
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -929,16 +929,18 @@ static int cpc_read(int cpu, struct cpc_register_resource *reg_res, u64 *val)
 
        if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
                u32 width = 8 << (reg->access_width - 1);
+               u32 val_u32;
                acpi_status status;
 
                status = acpi_os_read_port((acpi_io_address)reg->address,
-                                          (u32 *)val, width);
+                                          &val_u32, width);
                if (ACPI_FAILURE(status)) {
                        pr_debug("Error: Failed to read SystemIO port %llx\n",
                                 reg->address);
                        return -EFAULT;
                }
 
+               *val = val_u32;
                return 0;
        } else if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM && pcc_ss_id >= 0)
                vaddr = GET_PCC_VADDR(reg->address, pcc_ss_id);