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[PATCH v3 3/6] arm64: tlb: Convert the opencoded field modify

Luo Jie posted 6 patches 8 months ago
There is a newer version of this series
[PATCH v3 3/6] arm64: tlb: Convert the opencoded field modify
Posted by Luo Jie 8 months ago 
Replaced below code with the wrapper FIELD_MODIFY(MASK, &reg, val)
- reg &= ~MASK;
- reg |= FIELD_PREP(MASK, val);
The semantic patch that makes this change is available
in scripts/coccinelle/misc/field_modify.cocci.

More information about semantic patching is available at
https://coccinelle.gitlabpages.inria.fr/website

Signed-off-by: Luo Jie <quic_luoj@quicinc.com>
---
 arch/arm64/include/asm/tlbflush.h | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h
index eba1a98657f1..0d250ef4161c 100644
--- a/arch/arm64/include/asm/tlbflush.h
+++ b/arch/arm64/include/asm/tlbflush.h
@@ -112,8 +112,7 @@ static inline unsigned long get_trans_granule(void)
 	    level >= 0 && level <= 3) {					\
 		u64 ttl = level & 3;					\
 		ttl |= get_trans_granule() << 2;			\
-		arg &= ~TLBI_TTL_MASK;					\
-		arg |= FIELD_PREP(TLBI_TTL_MASK, ttl);			\
+		FIELD_MODIFY(TLBI_TTL_MASK, &arg, ttl);			\
 	}								\
 									\
 	__tlbi(op, arg);						\

-- 
2.34.1
Re: [PATCH v3 3/6] arm64: tlb: Convert the opencoded field modify
Posted by Russell King (Oracle) 8 months ago 
On Thu, Apr 17, 2025 at 06:47:10PM +0800, Luo Jie wrote:
> Replaced below code with the wrapper FIELD_MODIFY(MASK, &reg, val)
> - reg &= ~MASK;
> - reg |= FIELD_PREP(MASK, val);
> The semantic patch that makes this change is available
> in scripts/coccinelle/misc/field_modify.cocci.
> 
> More information about semantic patching is available at
> https://coccinelle.gitlabpages.inria.fr/website
> 
> Signed-off-by: Luo Jie <quic_luoj@quicinc.com>
> ---
>  arch/arm64/include/asm/tlbflush.h | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h
> index eba1a98657f1..0d250ef4161c 100644
> --- a/arch/arm64/include/asm/tlbflush.h
> +++ b/arch/arm64/include/asm/tlbflush.h
> @@ -112,8 +112,7 @@ static inline unsigned long get_trans_granule(void)
>  	    level >= 0 && level <= 3) {					\
>  		u64 ttl = level & 3;					\
>  		ttl |= get_trans_granule() << 2;			\
> -		arg &= ~TLBI_TTL_MASK;					\
> -		arg |= FIELD_PREP(TLBI_TTL_MASK, ttl);			\
> +		FIELD_MODIFY(TLBI_TTL_MASK, &arg, ttl);			\

This could equally be:
		arg = u64_replace_bits(arg, ttl, TLBI_TTL_MASK);

which already exists, so doesn't require a new macro to be introduced.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!
RE: [cocci] [PATCH v3 3/6] arm64: tlb: Convert the opencoded field modify
Posted by Keller, Jacob E 7 months, 3 weeks ago 

> -----Original Message-----
> From: cocci-request@inria.fr <cocci-request@inria.fr> On Behalf Of Russell King
> (Oracle)
> Sent: Thursday, April 17, 2025 11:11 AM
> To: Luo Jie <quic_luoj@quicinc.com>
> Cc: Yury Norov <yury.norov@gmail.com>; Rasmus Villemoes
> <linux@rasmusvillemoes.dk>; Julia Lawall <Julia.Lawall@inria.fr>; Nicolas Palix
> <nicolas.palix@imag.fr>; Catalin Marinas <catalin.marinas@arm.com>; Will
> Deacon <will@kernel.org>; Marc Zyngier <maz@kernel.org>; Oliver Upton
> <oliver.upton@linux.dev>; Joey Gouly <joey.gouly@arm.com>; Suzuki K Poulose
> <suzuki.poulose@arm.com>; Zenghui Yu <yuzenghui@huawei.com>; linux-
> kernel@vger.kernel.org; cocci@inria.fr; linux-arm-kernel@lists.infradead.org;
> kvmarm@lists.linux.dev; andrew@lunn.ch; quic_kkumarcs@quicinc.com;
> quic_linchen@quicinc.com; quic_leiwei@quicinc.com;
> quic_suruchia@quicinc.com; quic_pavir@quicinc.com
> Subject: Re: [cocci] [PATCH v3 3/6] arm64: tlb: Convert the opencoded field
> modify
> 
> On Thu, Apr 17, 2025 at 06:47:10PM +0800, Luo Jie wrote:
> > Replaced below code with the wrapper FIELD_MODIFY(MASK, &reg, val)
> > - reg &= ~MASK;
> > - reg |= FIELD_PREP(MASK, val);
> > The semantic patch that makes this change is available
> > in scripts/coccinelle/misc/field_modify.cocci.
> >
> > More information about semantic patching is available at
> > https://coccinelle.gitlabpages.inria.fr/website
> >
> > Signed-off-by: Luo Jie <quic_luoj@quicinc.com>
> > ---
> >  arch/arm64/include/asm/tlbflush.h | 3 +--
> >  1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/arch/arm64/include/asm/tlbflush.h
> b/arch/arm64/include/asm/tlbflush.h
> > index eba1a98657f1..0d250ef4161c 100644
> > --- a/arch/arm64/include/asm/tlbflush.h
> > +++ b/arch/arm64/include/asm/tlbflush.h
> > @@ -112,8 +112,7 @@ static inline unsigned long get_trans_granule(void)
> >  	    level >= 0 && level <= 3) {					\
> >  		u64 ttl = level & 3;					\
> >  		ttl |= get_trans_granule() << 2;			\
> > -		arg &= ~TLBI_TTL_MASK;					\
> > -		arg |= FIELD_PREP(TLBI_TTL_MASK, ttl);			\
> > +		FIELD_MODIFY(TLBI_TTL_MASK, &arg, ttl);			\
> 
> This could equally be:
> 		arg = u64_replace_bits(arg, ttl, TLBI_TTL_MASK);
> 
> which already exists, so doesn't require a new macro to be introduced.
> 

I had been looking for something like this the other day but was grepping for "FIELD_REPLACE" and similar which didn't find things.. Neat to know it exists already :D

> --
> RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
> FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!
Re: [PATCH v3 3/6] arm64: tlb: Convert the opencoded field modify
Posted by Jie Luo 7 months, 3 weeks ago 

On 4/18/2025 2:11 AM, Russell King (Oracle) wrote:
> On Thu, Apr 17, 2025 at 06:47:10PM +0800, Luo Jie wrote:
>> Replaced below code with the wrapper FIELD_MODIFY(MASK, &reg, val)
>> - reg &= ~MASK;
>> - reg |= FIELD_PREP(MASK, val);
>> The semantic patch that makes this change is available
>> in scripts/coccinelle/misc/field_modify.cocci.
>>
>> More information about semantic patching is available at
>> https://coccinelle.gitlabpages.inria.fr/website
>>
>> Signed-off-by: Luo Jie <quic_luoj@quicinc.com>
>> ---
>>   arch/arm64/include/asm/tlbflush.h | 3 +--
>>   1 file changed, 1 insertion(+), 2 deletions(-)
>>
>> diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h
>> index eba1a98657f1..0d250ef4161c 100644
>> --- a/arch/arm64/include/asm/tlbflush.h
>> +++ b/arch/arm64/include/asm/tlbflush.h
>> @@ -112,8 +112,7 @@ static inline unsigned long get_trans_granule(void)
>>   	    level >= 0 && level <= 3) {					\
>>   		u64 ttl = level & 3;					\
>>   		ttl |= get_trans_granule() << 2;			\
>> -		arg &= ~TLBI_TTL_MASK;					\
>> -		arg |= FIELD_PREP(TLBI_TTL_MASK, ttl);			\
>> +		FIELD_MODIFY(TLBI_TTL_MASK, &arg, ttl);			\
> 
> This could equally be:
> 		arg = u64_replace_bits(arg, ttl, TLBI_TTL_MASK);
> 
> which already exists, so doesn't require a new macro to be introduced.
> 
Looks like the new macro FIELD_MODIFY() is accepted by Yury, maybe we
can keep to use FIELD_MODIFY() with this change for better readability?
RE: [cocci] [PATCH v3 3/6] arm64: tlb: Convert the opencoded field modify
Posted by Keller, Jacob E 7 months, 3 weeks ago 

> -----Original Message-----
> From: cocci-request@inria.fr <cocci-request@inria.fr> On Behalf Of Jie Luo
> Sent: Wednesday, April 23, 2025 6:16 AM
> To: Russell King (Oracle) <linux@armlinux.org.uk>
> Cc: Yury Norov <yury.norov@gmail.com>; Rasmus Villemoes
> <linux@rasmusvillemoes.dk>; Julia Lawall <Julia.Lawall@inria.fr>; Nicolas Palix
> <nicolas.palix@imag.fr>; Catalin Marinas <catalin.marinas@arm.com>; Will
> Deacon <will@kernel.org>; Marc Zyngier <maz@kernel.org>; Oliver Upton
> <oliver.upton@linux.dev>; Joey Gouly <joey.gouly@arm.com>; Suzuki K Poulose
> <suzuki.poulose@arm.com>; Zenghui Yu <yuzenghui@huawei.com>; linux-
> kernel@vger.kernel.org; cocci@inria.fr; linux-arm-kernel@lists.infradead.org;
> kvmarm@lists.linux.dev; andrew@lunn.ch; quic_kkumarcs@quicinc.com;
> quic_linchen@quicinc.com; quic_leiwei@quicinc.com;
> quic_suruchia@quicinc.com; quic_pavir@quicinc.com
> Subject: Re: [cocci] [PATCH v3 3/6] arm64: tlb: Convert the opencoded field
> modify
> 
> 
> 
> On 4/18/2025 2:11 AM, Russell King (Oracle) wrote:
> > On Thu, Apr 17, 2025 at 06:47:10PM +0800, Luo Jie wrote:
> >> Replaced below code with the wrapper FIELD_MODIFY(MASK, &reg, val)
> >> - reg &= ~MASK;
> >> - reg |= FIELD_PREP(MASK, val);
> >> The semantic patch that makes this change is available
> >> in scripts/coccinelle/misc/field_modify.cocci.
> >>
> >> More information about semantic patching is available at
> >> https://coccinelle.gitlabpages.inria.fr/website
> >>
> >> Signed-off-by: Luo Jie <quic_luoj@quicinc.com>
> >> ---
> >>   arch/arm64/include/asm/tlbflush.h | 3 +--
> >>   1 file changed, 1 insertion(+), 2 deletions(-)
> >>
> >> diff --git a/arch/arm64/include/asm/tlbflush.h
> b/arch/arm64/include/asm/tlbflush.h
> >> index eba1a98657f1..0d250ef4161c 100644
> >> --- a/arch/arm64/include/asm/tlbflush.h
> >> +++ b/arch/arm64/include/asm/tlbflush.h
> >> @@ -112,8 +112,7 @@ static inline unsigned long get_trans_granule(void)
> >>   	    level >= 0 && level <= 3) {					\
> >>   		u64 ttl = level & 3;					\
> >>   		ttl |= get_trans_granule() << 2;			\
> >> -		arg &= ~TLBI_TTL_MASK;					\
> >> -		arg |= FIELD_PREP(TLBI_TTL_MASK, ttl);			\
> >> +		FIELD_MODIFY(TLBI_TTL_MASK, &arg, ttl);			\
> >
> > This could equally be:
> > 		arg = u64_replace_bits(arg, ttl, TLBI_TTL_MASK);
> >
> > which already exists, so doesn't require a new macro to be introduced.
> >
> Looks like the new macro FIELD_MODIFY() is accepted by Yury, maybe we
> can keep to use FIELD_MODIFY() with this change for better readability?

I'd prefer this version too rather than a pointer that modifies in place. Feels like it fits better with the other FIELD macros which don't take pointers and return their bits by value.

Patchew 2.1-devel-b67e4c2

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