Re: [PATCH v8 02/21] acpi: fix acpi_os_ioremap for arm64

[Rafael J. Wysocki]

On Wednesday, February 04, 2015 10:48:32 AM Russell King - ARM Linux wrote:
> On Tue, Feb 03, 2015 at 11:04:27PM +0100, Rafael J. Wysocki wrote:
> > On Tuesday, February 03, 2015 12:29:36 PM Mark Salter wrote:
> > > On Mon, 2015-02-02 at 23:14 +0100, Rafael J. Wysocki wrote:
> > > > On Monday, February 02, 2015 08:45:30 PM Hanjun Guo wrote:
> > > > > From: Mark Salter <msalter@xxxxxxxxxx>
> > > > > 
> > > > > The acpi_os_ioremap() function may be used to map normal RAM or IO
> > > > > regions. The current implementation simply uses ioremap_cache(). This
> > > > > will work for some architectures, but arm64 ioremap_cache() cannot be
> > > > > used to map IO regions which don't support caching. So for arm64, use
> > > > > ioremap() for non-RAM regions.
> > > > > 
> > > > > CC: Rafael J Wysocki <rjw@xxxxxxxxxxxxx>
> > > > > Signed-off-by: Mark Salter <msalter@xxxxxxxxxx>
> > > > > Signed-off-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
> > > > > ---
> > > > >  include/acpi/acpi_io.h | 6 ++++++
> > > > >  1 file changed, 6 insertions(+)
> > > > > 
> > > > > diff --git a/include/acpi/acpi_io.h b/include/acpi/acpi_io.h
> > > > > index 444671e..9d573db 100644
> > > > > --- a/include/acpi/acpi_io.h
> > > > > +++ b/include/acpi/acpi_io.h
> > > > > @@ -1,11 +1,17 @@
> > > > >  #ifndef _ACPI_IO_H_
> > > > >  #define _ACPI_IO_H_
> > > > >  
> > > > > +#include <linux/mm.h>
> > > > >  #include <linux/io.h>
> > > > >  
> > > > >  static inline void __iomem *acpi_os_ioremap(acpi_physical_address phys,
> > > > >  					    acpi_size size)
> > > > >  {
> > > > > +#ifdef CONFIG_ARM64
> > > > > +	if (!page_is_ram(phys >> PAGE_SHIFT))
> > > > > +		return ioremap(phys, size);
> > > > > +#endif
> > > > 
> > > > I don't want to see #ifdef CONFIG_ARM64 in this file.
> > > > 
> > > 
> > > How about something like:
> > > 
> > > From: Mark Salter <msalter@xxxxxxxxxx>
> > > Date: Tue, 3 Feb 2015 10:51:16 -0500
> > > Subject: [PATCH] acpi: fix acpi_os_ioremap for arm64
> > > 
> > > The acpi_os_ioremap() function may be used to map normal RAM or IO
> > > regions. The current implementation simply uses ioremap_cache(). This
> > > will work for some architectures, but arm64 ioremap_cache() cannot be
> > > used to map IO regions which don't support caching. So for arm64, use
> > > ioremap() for non-RAM regions.
> > > 
> > > CC: Rafael J Wysocki <rjw@xxxxxxxxxxxxx>
> > > Signed-off-by: Mark Salter <msalter@xxxxxxxxxx>
> > > ---
> > >  arch/arm64/include/asm/acpi.h | 14 ++++++++++++++
> > >  include/acpi/acpi_io.h        |  3 +++
> > >  2 files changed, 17 insertions(+)
> > > 
> > > diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
> > > index ea4d2b3..db82bc3 100644
> > > --- a/arch/arm64/include/asm/acpi.h
> > > +++ b/arch/arm64/include/asm/acpi.h
> > > @@ -14,6 +14,7 @@
> > >  
> > >  #include <linux/irqchip/arm-gic-acpi.h>
> > >  
> > > +#include <linux/mm.h>
> > >  #include <asm/smp_plat.h>
> > >  
> > >  /* Basic configuration for ACPI */
> > > @@ -100,4 +101,17 @@ static inline bool acpi_psci_use_hvc(void) { return false; }
> > >  static inline void acpi_init_cpus(void) { }
> > >  #endif /* CONFIG_ACPI */
> > >  
> > > +/*
> > > + * ACPI table mapping
> > > + */
> > > +static inline void __iomem *acpi_os_ioremap(acpi_physical_address phys,
> > > +					    acpi_size size)
> > > +{
> > > +	if (!page_is_ram(phys >> PAGE_SHIFT))
> > > +		return ioremap(phys, size);
> > > +
> > > +       return ioremap_cache(phys, size);
> > > +}
> > > +#define acpi_os_ioremap acpi_os_ioremap
> > 
> > If you want to do it this way, use __weak.  You won't need the #define then.
> > Otherwise, please use a proper CONFIG_ARCH_ symbol.
> 
> How does __weak work with inline functions?  I don't believe it does.

It doesn't work with inline funtions, but the function here doesn't have to be
inline.

> Moreover, __weak is positively harmful when you consider it adds bloat
> and dead code - the overriden __weak function is left behind in the
> resulting final image.

Fair enough.


-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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