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From:   "Rafael J. Wysocki" <rafael@kernel.org>
Date:   Thu, 5 Aug 2021 21:02:19 +0200
Message-ID: <CAJZ5v0jikZd_SMZxL0SAwVGH_-h8C9aUPH9LoG-PUFUZG3eLjA@mail.gmail.com>
Subject: Re: [PATCH v2 3/3] ACPI: Add memory semantics to acpi_os_map_memory()
To:     Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc:     Catalin Marinas <catalin.marinas@arm.com>,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Hanjun Guo <guohanjun@huawei.com>,
        Ard Biesheuvel <ardb@kernel.org>,
        Will Deacon <will@kernel.org>,
        Sudeep Holla <sudeep.holla@arm.com>,
        ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Veronika kabatova <vkabatov@redhat.com>,
        Robin Murphy <robin.murphy@arm.com>
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On Tue, Aug 3, 2021 at 11:16 AM Lorenzo Pieralisi
<lorenzo.pieralisi@arm.com> wrote:
>
> On Mon, Aug 02, 2021 at 05:46:22PM +0100, Catalin Marinas wrote:
> > On Mon, Aug 02, 2021 at 04:23:59PM +0100, Lorenzo Pieralisi wrote:
> > > The memory attributes attached to memory regions depend on architecture
> > > specific mappings.
> > >
> > > For some memory regions, the attributes specified by firmware (eg
> > > uncached) are not sufficient to determine how a memory region should be
> > > mapped by an OS (for instance a region that is define as uncached in
> > > firmware can be mapped as Normal or Device memory on arm64) and
> > > therefore the OS must be given control on how to map the region to match
> > > the expected mapping behaviour (eg if a mapping is requested with memory
> > > semantics, it must allow unaligned accesses).
> > >
> > > Rework acpi_os_map_memory() and acpi_os_ioremap() back-end to split
> > > them into two separate code paths:
> > >
> > > acpi_os_memmap() -> memory semantics
> > > acpi_os_ioremap() -> MMIO semantics
> > >
> > > The split allows the architectural implementation back-ends to detect
> > > the default memory attributes required by the mapping in question
> > > (ie the mapping API defines the semantics memory vs MMIO) and map the
> > > memory accordingly.
> > >
> > > Link: https://lore.kernel.org/linux-arm-kernel/31ffe8fc-f5ee-2858-26c5-0fd8bdd68702@arm.com
> > > Tested-by: Hanjun Guo <guohanjun@huawei.com>
> > > Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> > > Acked-by: Ard Biesheuvel <ardb@kernel.org>
> > > Cc: Ard Biesheuvel <ardb@kernel.org>
> > > Cc: Will Deacon <will@kernel.org>
> > > Cc: Hanjun Guo <guohanjun@huawei.com>
> > > Cc: Sudeep Holla <sudeep.holla@arm.com>
> > > Cc: Catalin Marinas <catalin.marinas@arm.com>
> > > Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
> >
> > For the arm64 bits:
> >
> > Acked-by: Catalin Marinas <catalin.marinas@arm.com>
> >
> > I presume this will get merged via the ACPI tree?
>
> Thank you, I don't know what's the best option in Rafael's opinion
> (of course if he is OK with the patches which are mostly touching
> ACPI code).

Well, I can apply them.

I'll queue them up tomorrow, but next week I'm on vacation, so they
will show up in linux-next after -rc6.  Hopefully, that's not too
late.