From: Ard Biesheuvel <ardb@kernel.org>
To: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Will Deacon <will@kernel.org>, Hanjun Guo <guohanjun@huawei.com>,
Sudeep Holla <sudeep.holla@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
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>
Subject: Re: [PATCH] ACPI: Add memory semantics to acpi_os_map_memory()
Date: Tue, 27 Jul 2021 12:09:47 +0200 [thread overview]
Message-ID: <CAMj1kXHwPXX9MxuF_cw1bq9v+qzH-M4-_ssES8WQq-YP3APthg@mail.gmail.com> (raw)
In-Reply-To: <20210727100645.GA7108@lpieralisi>
On Tue, 27 Jul 2021 at 12:06, Lorenzo Pieralisi
<lorenzo.pieralisi@arm.com> wrote:
>
> On Mon, Jul 26, 2021 at 05:55:33PM +0200, Ard Biesheuvel wrote:
> > On Mon, 26 Jul 2021 at 12:00, Lorenzo Pieralisi
> > <lorenzo.pieralisi@arm.com> 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
> > > Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> > > 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 patch in general
> >
> > Acked-by: Ard Biesheuvel <ardb@kernel.org>
>
> Thanks !
>
> [...]
>
> > > -void __iomem __ref
> > > -*acpi_os_map_iomem(acpi_physical_address phys, acpi_size size)
> > > +static void __iomem __ref
> > > +*__acpi_os_map_iomem(acpi_physical_address phys, acpi_size size, bool memory)
> > > {
> > > struct acpi_ioremap *map;
> > > void __iomem *virt;
> > > @@ -353,7 +356,7 @@ void __iomem __ref
> > >
> > > pg_off = round_down(phys, PAGE_SIZE);
> > > pg_sz = round_up(phys + size, PAGE_SIZE) - pg_off;
> > > - virt = acpi_map(phys, size);
> > > + virt = acpi_map(phys, size, memory);
> > > if (!virt) {
> > > mutex_unlock(&acpi_ioremap_lock);
> > > kfree(map);
> > > @@ -372,11 +375,17 @@ void __iomem __ref
> > > mutex_unlock(&acpi_ioremap_lock);
> > > return map->virt + (phys - map->phys);
> > > }
> > > +
> > > +void __iomem __ref
> > > +*acpi_os_map_iomem(acpi_physical_address phys, acpi_size size)
> >
> > I am aware that this just duplicated the prototype above, but I think
> > this should be
> >
> > void __iomem *__ref
> >
> > given that the __ref comes after the * in the prototype below.
>
> Yes I just moved/duplicated the prototype above but I believe this is
> consistent with include/acpi/acpi_io.h unless I have not understood
> what you meant ?
>
> It is probably worth changing it in both places to
>
> void __iomem *__ref
>
> ?
>
> I can do that with an additional patch.
>
Yes, as long as they are all mutually consistent. The __ref is not
part of the type at all, so it should not be between the void and the
*, even if the compiler appears to allow it.
> >
> > > +{
> > > + return __acpi_os_map_iomem(phys, size, false);
> > > +}
> > > EXPORT_SYMBOL_GPL(acpi_os_map_iomem);
> > >
> > > void *__ref acpi_os_map_memory(acpi_physical_address phys, acpi_size size)
> > > {
> > > - return (void *)acpi_os_map_iomem(phys, size);
> > > + return (void *)__acpi_os_map_iomem(phys, size, true);
> >
> > I think this should be (__force void *) to shut up sparse address
> > space warnings.
>
> Yes I can add that attribute in an additional patch and rebase this one
> on top of it.
>
> Thanks,
> Lorenzo
>
> >
> > > }
> > > EXPORT_SYMBOL_GPL(acpi_os_map_memory);
> > >
> > > diff --git a/include/acpi/acpi_io.h b/include/acpi/acpi_io.h
> > > index 027faa8883aa..a0212e67d6f4 100644
> > > --- a/include/acpi/acpi_io.h
> > > +++ b/include/acpi/acpi_io.h
> > > @@ -14,6 +14,14 @@ static inline void __iomem *acpi_os_ioremap(acpi_physical_address phys,
> > > }
> > > #endif
> > >
> > > +#ifndef acpi_os_memmap
> > > +static inline void __iomem *acpi_os_memmap(acpi_physical_address phys,
> > > + acpi_size size)
> > > +{
> > > + return ioremap_cache(phys, size);
> > > +}
> > > +#endif
> > > +
> > > extern bool acpi_permanent_mmap;
> > >
> > > void __iomem __ref
> > > --
> > > 2.31.0
> > >
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next prev parent reply other threads:[~2021-07-27 10:12 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-26 10:00 [PATCH] ACPI: Add memory semantics to acpi_os_map_memory() Lorenzo Pieralisi
2021-07-26 15:55 ` Ard Biesheuvel
2021-07-27 10:06 ` Lorenzo Pieralisi
2021-07-27 10:09 ` Ard Biesheuvel [this message]
2021-07-27 16:38 ` Lorenzo Pieralisi
2021-07-27 4:21 ` Hanjun Guo
2021-08-02 15:23 ` [PATCH v2 0/3] ACPI: Fix acpi_os_map_memory() memory semantics Lorenzo Pieralisi
2021-08-02 15:37 ` Ard Biesheuvel
2021-08-23 10:46 ` [PATCH RESEND v3] ACPI: Add memory semantics to acpi_os_map_memory() Lorenzo Pieralisi
2021-08-23 12:30 ` Catalin Marinas
2021-08-25 17:46 ` Rafael J. Wysocki
2021-08-02 15:23 ` [PATCH v2 1/3] ACPI: osl: Add __force attribute in acpi_os_map_iomem() cast Lorenzo Pieralisi
2021-08-10 16:45 ` Christoph Hellwig
2021-08-11 10:40 ` Ard Biesheuvel
2021-08-11 14:01 ` Lorenzo Pieralisi
2021-08-11 14:08 ` Christoph Hellwig
2021-08-11 14:55 ` Lorenzo Pieralisi
2021-08-16 9:58 ` Lorenzo Pieralisi
2021-08-16 10:21 ` Ard Biesheuvel
2021-08-16 10:59 ` Robin Murphy
2021-08-16 13:57 ` Rafael J. Wysocki
2021-08-02 15:23 ` [PATCH v2 2/3] ACPI: osl: Reorder acpi_os_map_iomem() __ref annotation Lorenzo Pieralisi
2021-08-02 15:23 ` [PATCH v2 3/3] ACPI: Add memory semantics to acpi_os_map_memory() Lorenzo Pieralisi
2021-08-02 16:46 ` Catalin Marinas
2021-08-03 9:16 ` Lorenzo Pieralisi
2021-08-05 19:02 ` Rafael J. Wysocki
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