linux-kernel - Re: [PATCH v1] arm64, lib: make ARM64 select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION not GENERIC_CPU_CACHE

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20251121104827.00005033@huawei.com>
Date: Fri, 21 Nov 2025 10:48:27 +0000
From: Jonathan Cameron <Jonathan.Cameron@...wei.com>
To: Randy Dunlap <rdunlap@...radead.org>
CC: Catalin Marinas <catalin.marinas@....com>, Conor Dooley
	<conor@...nel.org>, <linux-arm-kernel@...ts.infradead.org>, Conor Dooley
	<conor.dooley@...rochip.com>, Will Deacon <will@...nel.org>,
	<linux-kernel@...r.kernel.org>, Arnd Bergmann <arnd@...db.de>,
	<wangyushan12@...wei.com>
Subject: Re: [PATCH v1] arm64, lib: make ARM64 select
 ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION not GENERIC_CPU_CACHE_MAINTENANCE

On Thu, 20 Nov 2025 15:25:46 -0800
Randy Dunlap <rdunlap@...radead.org> wrote:

> On 11/20/25 1:40 PM, Catalin Marinas wrote:
> > On Thu, Nov 20, 2025 at 12:13:10PM -0800, Randy Dunlap wrote:  
> >> On 11/20/25 11:29 AM, Conor Dooley wrote:  
> >>> On Thu, Nov 20, 2025 at 05:30:46PM +0000, Catalin Marinas wrote:  
> >>>> On Wed, Nov 19, 2025 at 07:08:27PM +0000, Conor Dooley wrote:  
> >>>>> index 09aec4a1e13f..ac223e627bc5 100644
> >>>>> --- a/lib/Kconfig
> >>>>> +++ b/lib/Kconfig
> >>>>> @@ -544,8 +544,9 @@ config ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
> >>>>>  	bool
> >>>>>  
> >>>>>  config GENERIC_CPU_CACHE_MAINTENANCE
> >>>>> -	bool
> >>>>> -	select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
> >>>>> +	def_bool y
> >>>>> +	depends on ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
> >>>>> +	depends on ARM64  
> >>>>
> >>>> That's what we do if GENERIC_CPU_CACHE_MAINTENANCE depends on some arch
> >>>> code but that's not the case here. GENERIC_CPU_CACHE_MAINTENANCE is an
> >>>> alternative implementation that an arch can select if it does not
> >>>> provide its own. I find the current code without the above patch better.  
> >>>
> >>> Right, I am going to leave it as-is for now then. That's both you and I
> >>> (and presumably Jonathan) finding the current form more natural. Sorry
> >>> Randy!  
> >>
> >> Thanks. I tried.
> >>
> >> I still say that it makes no sense for something generic
> >> (GENERIC_CPU_CACHE_MAINTENANCE in lib/Kconfig) to inform the
> >> config system that the config has something $ARCH-specific
> >> (ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION).  
> > 
> > Yes, that's not great either but the solution with the GENERIC depending
> > on ARCH does work since there's no actual dependency between them.
> > 
> > As an alternative, I'm happy for arm64 to select both the ARCH and
> > GENERIC options if you think that works better.
> >   
> 
> Yes, I think that would be much better.
> Thanks.
> 

I'm fine with that as well (was where we were in earlier versions).
I'm offline for 10 days from tomorrow, but wangyushan +CC has been heavily
involved in this series throughout if we need to test anything etc.

For a patch that is basically just (this to me seems fine to squash
as well if that is easier)

Acked-by: Jonathan Cameron <jonathan.cameron@...wei.com>


diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 893e0af0bc51..b4507eeabc4c 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -20,6 +20,7 @@ config ARM64
        select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2
        select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE
        select ARCH_HAS_CACHE_LINE_SIZE
+       select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
        select ARCH_HAS_CC_PLATFORM
        select ARCH_HAS_CURRENT_STACK_POINTER
        select ARCH_HAS_DEBUG_VIRTUAL
diff --git a/lib/Kconfig b/lib/Kconfig
index e11136d188ae..2923924bea78 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -544,7 +544,6 @@ config ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION

 config GENERIC_CPU_CACHE_MAINTENANCE
        bool
-       select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION

 config ARCH_HAS_MEMREMAP_COMPAT_ALIGN
        bool

If not I'm guessing no one will mind too much if we tidy this up post or
late in merge window.

Thanks,

Jonathan