linux-kernel - Re: [PATCH v5 1/2] of: Documentation: Specify local APIC ID in "reg"

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: <20180313110153.vdtgljcvsbwiixwx@lakrids.cambridge.arm.com>
Date:   Tue, 13 Mar 2018 11:01:54 +0000
From:   Mark Rutland <mark.rutland@....com>
To:     Ivan Gorinov <ivan.gorinov@...el.com>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Frank Rowand <frowand.list@...il.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...hat.com>,
        Rob Herring <robh+dt@...nel.org>
Subject: Re: [PATCH v5 1/2] of: Documentation: Specify local APIC ID in "reg"

On Mon, Mar 12, 2018 at 03:21:48PM -0700, Ivan Gorinov wrote:
> Set the "reg" property to the processor's local APIC ID.
> Local APIC ID is assigned by hardware and may differ from CPU number.
> 
> Signed-off-by: Ivan Gorinov <ivan.gorinov@...el.com>
> ---
>  Documentation/devicetree/bindings/x86/ce4100.txt | 38 ++++++++++++++++++------
>  1 file changed, 29 insertions(+), 9 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/x86/ce4100.txt b/Documentation/devicetree/bindings/x86/ce4100.txt
> index b49ae59..5a4bd83 100644
> --- a/Documentation/devicetree/bindings/x86/ce4100.txt
> +++ b/Documentation/devicetree/bindings/x86/ce4100.txt
> @@ -7,17 +7,37 @@ Many of the "generic" devices like HPET or IO APIC have the ce4100
>  name in their compatible property because they first appeared in this
>  SoC.
>  
> -The CPU node
> -------------
> -	cpu@0 {
> -		device_type = "cpu";
> -		compatible = "intel,ce4100";
> -		reg = <0>;
> -		lapic = <&lapic0>;
> +The CPU nodes
> +-------------
> +
> +	cpus {
> +		#address-cells = <1>;
> +		#size-cells = <0>;
> +
> +		cpu@0 {
> +			device_type = "cpu";
> +			compatible = "intel,ce4100";
> +			reg = <0x00>;
> +		};
> +
> +		cpu@1 {
> +			device_type = "cpu";
> +			compatible = "intel,ce4100";
> +			reg = <0x02>;
> +		};

The unit-address (the bit after the '@' in the node name) should match
the reg, so this node should be named cpu@2.

If there's another ID associated with each CPU, then this should be
described in another property.

>  	};
>  
> -The reg property describes the CPU number. The lapic property points to
> -the local APIC timer.

Why was the lapic phandle removed?

Thanks,
Mark.

> +A "cpu" node describes one logical processor (hardware thread).
> +
> +Required properties:
> +
> +- device_type
> +	Device type, must be "cpu".
> +
> +- reg
> +	Local APIC ID, a unique number assigned to each processor by
> +	hardware. This ID is used to specify the destination of interrupt
> +	messages with "physical" destination mode, including startup IPI.
>  
>  The SoC node
>  ------------
> -- 
> 2.7.4
>