lkml.org 
[lkml]   [2021]   [Jul]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] ACPI: Add memory semantics to acpi_os_map_memory()
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.

>
> > +{
> > + 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
> >

\
 
 \ /
  Last update: 2021-07-27 12:07    [W:0.228 / U:0.152 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site