Re: [RFC 14/21] arm/cpu: Add sysreg generation scripts

[Eric Auger]

Hi Marc,
On 10/25/24 19:05, Marc Zyngier wrote:
> On Fri, 25 Oct 2024 11:17:33 +0100,
> Eric Auger <eric.auger@redhat.com> wrote:
>> Introduce scripts that automate the generation of system register
>> definitions from a given linux source tree arch/arm64/tools/sysreg.
>>
>> Invocation of
>> ./update-aarch64-sysreg-code.sh $PATH_TO_LINUX_SOURCE_TREE
>> in scripts directory do generate 2 qemu files:
>> - target/arm/cpu-sysreg-properties.c
>> - target/arm/cpu-sysregs.h
>>
>> cpu-sysregs.h creates defined for all system registers.
>> However cpu-sysreg-properties.c only cares about feature ID registers.
>>
>> update-aarch64-sysreg-code.sh calls two awk scripts.
>> gen-cpu-sysreg-properties.awk is inherited from kernel
>> arch/arm64/tools/gen-sysreg.awk. All credits to Mark Rutland
>> the original author of this script.
Sorry for the delay. I was out of the office last week.
> You really want to be careful with this. Both the script and the
> source file describing the registers are submitted to regular outburst
> of churn (I'm currently sitting on such a series). You really have to
> be prepared to see things breaking on each import.
OK thank you for the warning. It is now understood we cannot fully rely
on them and checks should be done on each run.
>
> That file has also been known to contain annoying mistakes, as it is
> all written by hand.
>
> Ideally, this would be directly generated from the ARM XML, which is a
> public set of files. However, the license attached to this package
> strictly prohibits its use in QEMU (or anywhere else). One day...
;-)

Eric
>
> Thanks,
>
>       M.
>