Re: [PATCH v1 1/2] ACPI: CPPC: Fix up I/O port access in cpc_read()

From: Huang Rui
Date: Wed Jan 12 2022 - 22:02:38 EST


On Wed, Jan 12, 2022 at 07:26:32PM +0100, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
>
> 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@xxxxxxxxxx>
> Suggested-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> Link: https://lore.kernel.org/linux-acpi/20220111092928.GA24968@kili/
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>

Acked-by: Huang Rui <ray.huang@xxxxxxx>

> ---
> drivers/acpi/cppc_acpi.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> Index: linux-pm/drivers/acpi/cppc_acpi.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/cppc_acpi.c
> +++ linux-pm/drivers/acpi/cppc_acpi.c
> @@ -929,16 +929,18 @@ static int cpc_read(int cpu, struct cpc_
>
> 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);
>
>
>