Re: [PATCH 1/3] scripts: introduce scripts/update-aarch64-sysreg-code.py

[Cornelia Huck <cohuck@redhat.com>]

On Mon, Dec 08 2025, Eric Auger <eric.auger@redhat.com> wrote:

> Introduce a script that takes as input the Registers.json file
> delivered in the AARCHMRS Features Model downloadable from the
> Arm Developer A-Profile Architecture Exploration Tools page:
> https://developer.arm.com/Architectures/A-Profile%20Architecture#Downloads
> and outputs the list of ID regs in target/arm/cpu-sysregs.h.inc
> under the form of DEF(<name>, <op0>, <op1>, <crn>, <crm>, <op2>).
>
> We only care about IDregs with opcodes satisfying:
> op0 = 3, op1 within [0, 3], crn = 0, crm within [0, 7], op2 within [0, 7]
>
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>
> ---
>
> This was tested with https://developer.arm.com/-/cdn-downloads/permalink/Exploration-Tools-OS-Machine-Readable-Data/AARCHMRS_BSD/AARCHMRS_OPENSOURCE_A_profile_FAT-2025-09_ASL0.tar.gz
>
> Discussion about undesired generated regs can be found in
> https://lore.kernel.org/all/CAFEAcA9OXi4v+hdBMamQv85HYp2EqxOA5=nfsdZ5E3nf8RP_pw@mail.gmail.com/
> ---
>  scripts/update-aarch64-sysreg-code.py | 133 ++++++++++++++++++++++++++
>  1 file changed, 133 insertions(+)
>  create mode 100755 scripts/update-aarch64-sysreg-code.py
>
> diff --git a/scripts/update-aarch64-sysreg-code.py b/scripts/update-aarch64-sysreg-code.py
> new file mode 100755
> index 0000000000..c7b31035d1
> --- /dev/null
> +++ b/scripts/update-aarch64-sysreg-code.py

(...)

> +if __name__ == "__main__":
> +    # Single arg expectedr: the path to the Registers.json file
> +    if len(sys.argv) < 2:
> +        print("Usage: scripts/update-aarch64-sysreg-code.py <path_to_registers_json>")
> +        sys.exit(1)
> +    else:
> +        json_file_path = sys.argv[1]
> +
> +    extracted_registers = extract_idregs_from_registers_json(json_file_path)
> +
> +    if extracted_registers:
> +        output_list = extracted_registers.items()
> +
> +        # Sort by register name
> +        sorted_output = sorted(output_list, key=lambda item: item[0])
> +
> +        # format lines as DEF(<name>, <op0>, <op1>, <crn>, <crm>, <op2>)
> +        final_output = ""
> +        for reg_name, encoding in sorted_output:
> +            reformatted_encoding = encoding.replace(" ", ", ")
> +            final_output += f"DEF({reg_name}, {reformatted_encoding})\n"
> +
> +        with open("target/arm/cpu-sysregs.h.inc", 'w') as f:
> +            f.write("/* SPDX-License-Identifier: BSD-3-Clause */\n\n")
> +            f.write("/* This file is autogenerated by ")
> +            f.write("scripts/update-aarch64-sysreg-code.py */\n\n")

I'm wondering if there is an easy way to log the version of the json
file this has been generated against. If not, putting the information
into the commit message when updating is probably sufficient.

> +            f.write(final_output)
> +        print(f"updated target/arm/cpu-sysregs.h.inc")