RE: [PATCH 3.4 52/65] ACPICA: Tables: Fix an issue that FACS initialization is performed twice

[Moore, Robert]

> -----Original Message-----
> From: lizf@xxxxxxxxxx [mailto:lizf@xxxxxxxxxx]
> Sent: Monday, October 19, 2015 5:48 PM
> To: stable@xxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx; Zheng, Lv; Moore, Robert; Wysocki,
> Rafael J; Zefan Li
> Subject: [PATCH 3.4 52/65] ACPICA: Tables: Fix an issue that FACS
> initialization is performed twice
> 
> From: Lv Zheng <lv.zheng@xxxxxxxxx>
> 
> 3.4.110-rc1 review patch.  If anyone has any objections, please let me
> know.
> 
> ------------------
> 
> 
> commit c04be18448355441a0c424362df65b6422e27bda upstream.
> 
> ACPICA commit 90f5332a15e9d9ba83831ca700b2b9f708274658
> 
> This patch adds a new FACS initialization flag for acpi_tb_initialize().
> acpi_enable_subsystem() might be invoked several times in OS bootup
> process, and we don't want FACS initialization to be invoked twice. Lv
> Zheng.
> 

Isn't calling acpi_enable_subsystem more than once essentially an OS bug?






> Link: https://github.com/acpica/acpica/commit/90f5332a
> Signed-off-by: Lv Zheng <lv.zheng@xxxxxxxxx>
> Signed-off-by: Bob Moore <robert.moore@xxxxxxxxx>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> [lizf: Backported to 3.4: adjust filename]
> Signed-off-by: Zefan Li <lizefan@xxxxxxxxxx>
> ---
>  drivers/acpi/acpica/utxface.c | 10 ++++++----
>  include/acpi/actypes.h        |  1 +
>  2 files changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/acpi/acpica/utxface.c b/drivers/acpi/acpica/utxface.c
> index afa94f5..0985ab7 100644
> --- a/drivers/acpi/acpica/utxface.c
> +++ b/drivers/acpi/acpica/utxface.c
> @@ -166,10 +166,12 @@ acpi_status acpi_enable_subsystem(u32 flags)
>  	 * Obtain a permanent mapping for the FACS. This is required for the
>  	 * Global Lock and the Firmware Waking Vector
>  	 */
> -	status = acpi_tb_initialize_facs();
> -	if (ACPI_FAILURE(status)) {
> -		ACPI_WARNING((AE_INFO, "Could not map the FACS table"));
> -		return_ACPI_STATUS(status);
> +	if (!(flags & ACPI_NO_FACS_INIT)) {
> +		status = acpi_tb_initialize_facs();
> +		if (ACPI_FAILURE(status)) {
> +			ACPI_WARNING((AE_INFO, "Could not map the FACS table"));
> +			return_ACPI_STATUS(status);
> +		}
>  	}
>  #endif				/* !ACPI_REDUCED_HARDWARE */
> 
> diff --git a/include/acpi/actypes.h b/include/acpi/actypes.h index
> 6d52429..0460073 100644
> --- a/include/acpi/actypes.h
> +++ b/include/acpi/actypes.h
> @@ -495,6 +495,7 @@ typedef u64 acpi_integer;
>  #define ACPI_NO_ACPI_ENABLE             0x10
>  #define ACPI_NO_DEVICE_INIT             0x20
>  #define ACPI_NO_OBJECT_INIT             0x40
> +#define ACPI_NO_FACS_INIT               0x80
> 
>  /*
>   * Initialization state
> --
> 1.9.1

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