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Peter Anvin" , Peter Zijlstra , Andrew Morton , Arnd Bergmann , Drew Fustini , Linus Walleij , Alexandre Belloni , Krzysztof Kozlowski , james.morse@arm.com, Will Deacon , Davidlohr Bueso , linuxarm@huawei.com, Yushan Wang , Lorenzo Pieralisi , Mark Rutland , Dave Hansen , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, Andy Lutomirski , Dave Jiang References: <20251117104800.2041329-1-Jonathan.Cameron@huawei.com> <20251117104800.2041329-4-Jonathan.Cameron@huawei.com> <3bf1793a-2ffd-4017-b4bf-dc63f3a2a7c8@infradead.org> <20251117-definite-uncounted-7cc07a377a71@spud> <20251118093041.00000c9e@huawei.com> Content-Language: en-US From: Randy Dunlap In-Reply-To: <20251118093041.00000c9e@huawei.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Stat-Signature: 8jkakfj7ttaaa78jgy3f1u5d1coext5j X-Rspam-User: X-Rspamd-Queue-Id: 1611A40005 X-Rspamd-Server: rspam10 X-HE-Tag: 1763515121-695768 X-HE-Meta: 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 dF0Kqh61 w3y45oiiodBphDHckn8SIcoVMKdm0F4gHeN8DXxFo092t37YcotwYSy/zyvH1vAtfqRgPACocle/bOAhyioqwiJnTFXKWlMM/NCXxc2EB3xQF/9IkAb19kMqOTJKPw359dY7ysYcSz1zsa0xwPszhSu9veS/OIHJ+KabjfI+vjRfqJq8EfUU3kR0Tuwc9l8DSPaQrxv/HgotzcGPOcy0TWb3LlXljNE10oHMrKE/iqtFaneovO/gWK2B0WVg0XZYWmHpnBv9+1ssfmwh6JdNouHvsSMzXmrSWQnlnUFXS1Fu8F1oIkhW9xEBrkaGYMO3C7YsV0ssvTrK07Qe4SyaW6haXXNj2pNr4h9/3EAG4HKBWpvo= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 11/18/25 1:30 AM, Jonathan Cameron wrote: > On Tue, 18 Nov 2025 00:13:07 +0000 > Conor Dooley wrote: > >> On Mon, Nov 17, 2025 at 10:51:11AM -0800, Randy Dunlap wrote: >>> Hi, >>> >>> On 11/17/25 2:47 AM, Jonathan Cameron wrote: >>>> diff --git a/lib/Kconfig b/lib/Kconfig >>>> index e629449dd2a3..e11136d188ae 100644 >>>> --- a/lib/Kconfig >>>> +++ b/lib/Kconfig >>>> @@ -542,6 +542,10 @@ config MEMREGION >>>> config ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION >>>> bool >>>> >>>> +config GENERIC_CPU_CACHE_MAINTENANCE >>>> + bool >>>> + select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION >>>> + >>>> config ARCH_HAS_MEMREMAP_COMPAT_ALIGN >>>> bool >>> >>> Architectures and/or platforms select ARCH_HAS_*. >>> >>> With this change above, it becomes the only entry in >>> lib/Kconfig that does "select ARCH_HAS_anytning". >>> >>> so I think this is wrong, back*wards. >> >> Maybe it is backwards, but I feel like this way is more logical. ARM64 >> has memregion invalidation only because this generic approach is >> enabled, so the arch selects what it needs to get the support. > > Exactly this. Catalin requested this form in response to an earlier > version where arm64 Kconfig just had both selects for pretty much that > reason. This is expected to be used on a subset of architectures. > It is similar to things like GENERIC_ARCH_NUMA in this respect (though the > arch_numa_init() etc in there are called only from other arch code > so no ARCH_HAS_ symbols are associated with them). > >> Alternatively, something like > > I'm fine with this solution if Randy prefers it. I do much prefer this alternative. > Thanks for your help with this. Thanks for listening. >> | diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig >> | index 5f7f63d24931..75b2507f7eb2 100644 >> | --- a/arch/arm64/Kconfig >> | +++ b/arch/arm64/Kconfig >> | @@ -21,6 +21,7 @@ config ARM64 >> | select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE >> | select ARCH_HAS_CACHE_LINE_SIZE >> | select ARCH_HAS_CC_PLATFORM >> | + select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION >> | select ARCH_HAS_CURRENT_STACK_POINTER >> | select ARCH_HAS_DEBUG_VIRTUAL >> | select ARCH_HAS_DEBUG_VM_PGTABLE >> | @@ -146,7 +147,6 @@ config ARM64 >> | select GENERIC_ARCH_TOPOLOGY >> | select GENERIC_CLOCKEVENTS_BROADCAST >> | select GENERIC_CPU_AUTOPROBE >> | - select GENERIC_CPU_CACHE_MAINTENANCE >> | select GENERIC_CPU_DEVICES >> | select GENERIC_CPU_VULNERABILITIES >> | select GENERIC_EARLY_IOREMAP >> | diff --git a/lib/Kconfig b/lib/Kconfig >> | 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 >> | >> | config ARCH_HAS_MEMREMAP_COMPAT_ALIGN >> | bool >> implies (to me at least) that arm64 has memregion invalidation as an >> architectural feature and that the GENERIC_CPU_CACHE_MAINTENANCE option >> is a just common cross-arch code, like generic entry etc, rather than >> being the option gating the drivers that provide the feature in the >> first place. >> >> I didn't really care which way it went, and was gonna post something to >> squash and avoid another revision, but I found the resultant Kconfig >> setup to be make less sense to me than what came before. If the switched >> around version is less likely to be problematic etc, then sure, but I >> amn't convinced by switching it at a first glance. -- ~Randy