Add the helper FIELD_MODIFY() to the FIELD_XXX family of bitfield
macros. It is functionally similar as xxx_replace_bits(), but adds
the compile time checking to catch incorrect parameter type errors.

This series also converts the four instances of opencoded FIELD_MODIFY()
that are found in the core kernel files, to instead use the new
FIELD_MODIFY() macro. This is achieved with Coccinelle, by adding
the script field_modify.cocci.

The changes are validated on IPQ9574 SoC which uses ARM64 architecture.

Signed-off-by: Luo Jie <quic_luoj@quicinc.com>
---
Changes in v4:
- Add org, report and context mode for coccinelle script.
- Fix other comments on coccinelle script patch.
- Remove the FIELD_MODIFY patch as it is merged.
- Link to v3: https://lore.kernel.org/r/20250417-field_modify-v3-0-6f7992aafcb7@quicinc.com

Changes in v3:
- Correct the order of header files included.
- Add the Coccinelle script field_modify.cocci..
- Convert the opencoded FIELD_MODIFY() variants inside arm64 directory,
  identified by field_modify.cocci.
- Link to v2: https://lore.kernel.org/all/20250410131048.2054791-1-quic_luoj@quicinc.com/

Changes in v2:
- Update the documented example for FIELD_MODIFY().
- Improve the commit message to describe the need for the change.
- Link to v1: https://lore.kernel.org/all/20250318071526.1836194-1-quic_luoj@quicinc.com/

---
Luo Jie (5):
      coccinelle: misc: Add field_modify script
      arm64: tlb: Convert the opencoded field modify
      arm64: nvhe: Convert the opencoded field modify
      arm64: kvm: Convert the opencoded field modify
      arm64: mm: Convert the opencoded field modify

 arch/arm64/include/asm/tlbflush.h          |  3 +-
 arch/arm64/kvm/hyp/include/nvhe/memory.h   |  3 +-
 arch/arm64/kvm/vgic/vgic-mmio-v3.c         |  6 +--
 arch/arm64/mm/context.c                    |  3 +-
 scripts/coccinelle/misc/field_modify.cocci | 61 ++++++++++++++++++++++++++++++
 5 files changed, 66 insertions(+), 10 deletions(-)
---
base-commit: 0bb71d301869446810a0b13d3da290bd455d7c78
change-id: 20250612-field_modify-27139f673881

Best regards,
-- 
Luo Jie <quic_luoj@quicinc.com>

On Thu, 12 Jun 2025 14:46:07 +0100,
Luo Jie <quic_luoj@quicinc.com> wrote:
> 
> Add the helper FIELD_MODIFY() to the FIELD_XXX family of bitfield
> macros. It is functionally similar as xxx_replace_bits(), but adds
> the compile time checking to catch incorrect parameter type errors.
> 
> This series also converts the four instances of opencoded FIELD_MODIFY()
> that are found in the core kernel files, to instead use the new
> FIELD_MODIFY() macro. This is achieved with Coccinelle, by adding
> the script field_modify.cocci.
> 
> The changes are validated on IPQ9574 SoC which uses ARM64 architecture.
> 
> Signed-off-by: Luo Jie <quic_luoj@quicinc.com>

I already indicated that the *pre-existing* set of helpers are enough
for what we want to do, that we *already* use them for KVM/arm64, and
that I didn't need nor want two ways to do the same thing in the same
code base.

My opinion hasn't changed on that front, and I don't see a point in
these patches.

	M.

-- 
Without deviation from the norm, progress is not possible.

On 6/12/2025 10:11 PM, Marc Zyngier wrote:
> On Thu, 12 Jun 2025 14:46:07 +0100,
> Luo Jie <quic_luoj@quicinc.com> wrote:
>>
>> Add the helper FIELD_MODIFY() to the FIELD_XXX family of bitfield
>> macros. It is functionally similar as xxx_replace_bits(), but adds
>> the compile time checking to catch incorrect parameter type errors.
>>
>> This series also converts the four instances of opencoded FIELD_MODIFY()
>> that are found in the core kernel files, to instead use the new
>> FIELD_MODIFY() macro. This is achieved with Coccinelle, by adding
>> the script field_modify.cocci.
>>
>> The changes are validated on IPQ9574 SoC which uses ARM64 architecture.
>>
>> Signed-off-by: Luo Jie <quic_luoj@quicinc.com>
> 
> I already indicated that the *pre-existing* set of helpers are enough
> for what we want to do, that we *already* use them for KVM/arm64, and
> that I didn't need nor want two ways to do the same thing in the same
> code base.
> 
> My opinion hasn't changed on that front, and I don't see a point in
> these patches.
> 
> 	M.
> 

OK. I will drop the ARM64 patches and only keep the coccinelle script
patch in the next version.