linux-kernel - Re: [PATCH V2 2/2] arm64/mm: Add remaining TLBI_XXX

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Message-ID: <20251028124334.00001e77@huawei.com>
Date: Tue, 28 Oct 2025 12:43:34 +0000
From: Jonathan Cameron <jonathan.cameron@...wei.com>
To: Anshuman Khandual <anshuman.khandual@....com>
CC: <linux-arm-kernel@...ts.infradead.org>, <ben.horgan@....com>, "Catalin
 Marinas" <catalin.marinas@....com>, Will Deacon <will@...nel.org>, "Marc
 Zyngier" <maz@...nel.org>, Oliver Upton <oliver.upton@...ux.dev>,
	<linux-kernel@...r.kernel.org>, <kvmarm@...ts.linux.dev>
Subject: Re: [PATCH V2 2/2] arm64/mm: Add remaining TLBI_XXX_MASK macros

On Mon, 27 Oct 2025 07:06:45 +0530
Anshuman Khandual <anshuman.khandual@....com> wrote:

> On 24/10/25 4:30 PM, Jonathan Cameron wrote:
> > On Fri, 24 Oct 2025 05:02:07 +0100
> > Anshuman Khandual <anshuman.khandual@....com> wrote:
> >   
> >> Add remaining TLBI_XXX_MASK macros and replace current open encoded fields.
> >> While here replace hard coded page size based shifts but with derived ones
> >> via ilog2() thus adding some required context.
> >>
> >> TLBI_TTL_MASK has been split into separate TLBI_TTL_MASK and TLBI_TG_MASK
> >> as appropriate because currently it simultaneously contains both page size
> >> and translation table level information. KVM on arm64 has been updated to
> >> accommodate these changes to TLBI_TTL_MASK.
> >>
> >> Cc: Catalin Marinas <catalin.marinas@....com>
> >> Cc: Will Deacon <will@...nel.org>
> >> Cc: Marc Zyngier <maz@...nel.org>
> >> Cc: Oliver Upton <oliver.upton@...ux.dev>
> >> Cc: linux-arm-kernel@...ts.infradead.org
> >> Cc: linux-kernel@...r.kernel.org
> >> Cc: kvmarm@...ts.linux.dev
> >> Signed-off-by: Anshuman Khandual <anshuman.khandual@....com>
> >> ---
> >>  arch/arm64/include/asm/tlbflush.h | 26 ++++++++++++++++++--------
> >>  arch/arm64/kvm/nested.c           |  8 +++++---
> >>  2 files changed, 23 insertions(+), 11 deletions(-)
> >>
> >> diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h
> >> index 131096094f5b..cf75fc2a06c3 100644
> >> --- a/arch/arm64/include/asm/tlbflush.h
> >> +++ b/arch/arm64/include/asm/tlbflush.h
> >> @@ -57,9 +57,10 @@
> >>  /* This macro creates a properly formatted VA operand for the TLBI */
> >>  #define __TLBI_VADDR(addr, asid)				\
> >>  	({							\
> >> -		unsigned long __ta = (addr) >> 12;		\
> >> -		__ta &= GENMASK_ULL(43, 0);			\
> >> -		__ta |= (unsigned long)(asid) << 48;		\
> >> +		unsigned long __ta = (addr) >> ilog2(SZ_4K);	\
> >> +		__ta &= TLBI_BADDR_MASK;			\
> >> +		__ta &= ~TLBI_ASID_MASK;			\
> >> +		__ta |= FIELD_PREP(TLBI_ASID_MASK, asid);	\  
> > I think you can replace the two lines above with
> > 		FIELD_MODIFY(TLBI_ASID_MASK, &__ta, asid);
> > 
> > It's a small reduction in code but I don't mind much either way.  
> 
> Right. FIELD_MODIFY() might be appropriate in this scenario but
> there will be some additional code churn needed. I don't have a
> strong opinion either way.
> 
> --- a/arch/arm64/include/asm/tlbflush.h
> +++ b/arch/arm64/include/asm/tlbflush.h
> @@ -55,13 +55,12 @@
>  } while (0)
> 
>  /* This macro creates a properly formatted VA operand for the TLBI */
> -#define __TLBI_VADDR(addr, asid)                               \
> -       ({                                                      \
> -               unsigned long __ta = (addr) >> ilog2(SZ_4K);    \
> -               __ta &= TLBI_BADDR_MASK;                        \
> -               __ta &= ~TLBI_ASID_MASK;                        \
> -               __ta |= FIELD_PREP(TLBI_ASID_MASK, asid);       \
> -               __ta;                                           \
> +#define __TLBI_VADDR(addr, asid)                                       \
> +       ({                                                              \
> +               unsigned long __ta = (addr) >> ilog2(SZ_4K);            \
> +               __ta &= TLBI_BADDR_MASK;                                \
> +               __ta |= FIELD_MODIFY(TLBI_ASID_MASK, &__ta, asid);      \
		  FIELD_MODIFY(TLBI_ASID_MASK, &__tab, asid);

as it's done in place in the second parameter.