linux-kernel - Re: [PATCH RFC v3 02/21] ACPI: processor: Add support for processors described as container packages

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20231214173626.00005062@Huawei.com>
Date:   Thu, 14 Dec 2023 17:36:26 +0000
From:   Jonathan Cameron <Jonathan.Cameron@...wei.com>
To:     "Russell King (Oracle)" <rmk+kernel@...linux.org.uk>
CC:     <linux-pm@...r.kernel.org>, <loongarch@...ts.linux.dev>,
        <linux-acpi@...r.kernel.org>, <linux-arch@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-riscv@...ts.infradead.org>, <kvmarm@...ts.linux.dev>,
        <x86@...nel.org>, <acpica-devel@...ts.linuxfoundation.org>,
        <linux-csky@...r.kernel.org>, <linux-doc@...r.kernel.org>,
        <linux-ia64@...r.kernel.org>, <linux-parisc@...r.kernel.org>,
        Salil Mehta <salil.mehta@...wei.com>,
        Jean-Philippe Brucker <jean-philippe@...aro.org>,
        <jianyong.wu@....com>, <justin.he@....com>,
        James Morse <james.morse@....com>
Subject: Re: [PATCH RFC v3 02/21] ACPI: processor: Add support for
 processors described as container packages

On Wed, 13 Dec 2023 12:49:21 +0000
Russell King (Oracle) <rmk+kernel@...linux.org.uk> wrote:

> From: James Morse <james.morse@....com>
> 
> ACPI has two ways of describing processors in the DSDT. From ACPI v6.5,
> 5.2.12:
> 
> "Starting with ACPI Specification 6.3, the use of the Processor() object
> was deprecated. Only legacy systems should continue with this usage. On
> the Itanium architecture only, a _UID is provided for the Processor()
> that is a string object. This usage of _UID is also deprecated since it
> can preclude an OSPM from being able to match a processor to a
> non-enumerable device, such as those defined in the MADT. From ACPI
> Specification 6.3 onward, all processor objects for all architectures
> except Itanium must now use Device() objects with an _HID of ACPI0007,
> and use only integer _UID values."
> 
> Also see https://uefi.org/specs/ACPI/6.5/08_Processor_Configuration_and_Control.html#declaring-processors
> 
> Duplicate descriptions are not allowed, the ACPI processor driver already
> parses the UID from both devices and containers. acpi_processor_get_info()
> returns an error if the UID exists twice in the DSDT.
> 
> The missing probe for CPUs described as packages creates a problem for
> moving the cpu_register() calls into the acpi_processor driver, as CPUs
> described like this don't get registered, leading to errors from other
> subsystems when they try to add new sysfs entries to the CPU node.
> (e.g. topology_sysfs_init()'s use of topology_add_dev() via cpuhp)
> 
> To fix this, parse the processor container and call acpi_processor_add()
> for each processor that is discovered like this. The processor container
> handler is added with acpi_scan_add_handler(), so no detach call will
> arrive.
> 
> Qemu TCG describes CPUs using processor devices in a processor container.
> For more information, see build_cpus_aml() in Qemu hw/acpi/cpu.c and
> https://uefi.org/specs/ACPI/6.5/08_Processor_Configuration_and_Control.html#processor-container-device
> 
> Signed-off-by: James Morse <james.morse@....com>
> Tested-by: Miguel Luis <miguel.luis@...cle.com>
> Tested-by: Vishnu Pajjuri <vishnu@...amperecomputing.com>
> Tested-by: Jianyong Wu <jianyong.wu@....com>
> ---
> Outstanding comments:
>  https://lore.kernel.org/r/20230914145353.000072e2@Huawei.com
Looks like you resolved those (were all patch description things).

So I'm happy.
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>

Thanks,

J
>  https://lore.kernel.org/r/50571c2f-aa3c-baeb-3add-cd59e0eddc02@redhat.com
> ---
>  drivers/acpi/acpi_processor.c | 22 ++++++++++++++++++++++
>  1 file changed, 22 insertions(+)
> 
> diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
> index 4fe2ef54088c..6a542e0ce396 100644
> --- a/drivers/acpi/acpi_processor.c
> +++ b/drivers/acpi/acpi_processor.c
> @@ -626,9 +626,31 @@ static struct acpi_scan_handler processor_handler = {
>  	},
>  };
>  
> +static acpi_status acpi_processor_container_walk(acpi_handle handle,
> +						 u32 lvl,
> +						 void *context,
> +						 void **rv)
> +{
> +	struct acpi_device *adev;
> +	acpi_status status;
> +
> +	adev = acpi_get_acpi_dev(handle);
> +	if (!adev)
> +		return AE_ERROR;
> +
> +	status = acpi_processor_add(adev, &processor_device_ids[0]);
> +	acpi_put_acpi_dev(adev);
> +
> +	return status;
> +}
> +
>  static int acpi_processor_container_attach(struct acpi_device *dev,
>  					   const struct acpi_device_id *id)
>  {
> +	acpi_walk_namespace(ACPI_TYPE_PROCESSOR, dev->handle,
> +			    ACPI_UINT32_MAX, acpi_processor_container_walk,
> +			    NULL, NULL, NULL);
> +
>  	return 1;
>  }
>