linux-kernel - Re: [PATCH v1 04/47] pci: add pci_ioremap_wc

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20150325200636.GC12247@wotan.suse.de>
Date:	Wed, 25 Mar 2015 21:06:36 +0100
From:	"Luis R. Rodriguez" <mcgrof@...e.com>
To:	Andy Lutomirski <luto@...capital.net>
Cc:	"Luis R. Rodriguez" <mcgrof@...not-panic.com>,
	Ingo Molnar <mingo@...hat.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	"H. Peter Anvin" <hpa@...or.com>, Juergen Gross <jgross@...e.com>,
	Jan Beulich <JBeulich@...e.com>, Borislav Petkov <bp@...e.de>,
	Suresh Siddha <suresh.b.siddha@...el.com>,
	venkatesh.pallipadi@...el.com, Dave Airlie <airlied@...hat.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Linux Fbdev development list <linux-fbdev@...r.kernel.org>,
	X86 ML <x86@...nel.org>,
	"xen-devel@...ts.xenproject.org" <xen-devel@...ts.xenproject.org>,
	Ingo Molnar <mingo@...e.hu>,
	Daniel Vetter <daniel.vetter@...ll.ch>,
	Antonino Daplas <adaplas@...il.com>,
	Jean-Christophe Plagniol-Villard <plagnioj@...osoft.com>,
	Tomi Valkeinen <tomi.valkeinen@...com>
Subject: Re: [PATCH v1 04/47] pci: add pci_ioremap_wc_bar()

On Fri, Mar 20, 2015 at 04:50:32PM -0700, Andy Lutomirski wrote:
> On Fri, Mar 20, 2015 at 4:17 PM, Luis R. Rodriguez
> <mcgrof@...not-panic.com> wrote:
> > From: "Luis R. Rodriguez" <mcgrof@...e.com>
> >
> > This lets drivers take advanate of PAT when available. This
> > should help with the transition of converting video drivers over
> > to ioremap_wc() to help with the goal of eventually using
> > _PAGE_CACHE_UC over _PAGE_CACHE_UC_MINUS on x86 on
> > ioremap_nocache() (de33c442e)
> >
> > Cc: Suresh Siddha <suresh.b.siddha@...el.com>
> > Cc: Venkatesh Pallipadi <venkatesh.pallipadi@...el.com>
> > Cc: Ingo Molnar <mingo@...e.hu>
> > Cc: Thomas Gleixner <tglx@...utronix.de>
> > Cc: Juergen Gross <jgross@...e.com>
> > Cc: Daniel Vetter <daniel.vetter@...ll.ch>
> > Cc: Andy Lutomirski <luto@...capital.net>
> > Cc: Dave Airlie <airlied@...hat.com>
> > Cc: Antonino Daplas <adaplas@...il.com>
> > Cc: Jean-Christophe Plagniol-Villard <plagnioj@...osoft.com>
> > Cc: Tomi Valkeinen <tomi.valkeinen@...com>
> > Cc: linux-fbdev@...r.kernel.org
> > Cc: linux-kernel@...r.kernel.org
> > Signed-off-by: Luis R. Rodriguez <mcgrof@...e.com>
> > ---
> >  drivers/pci/pci.c   | 14 ++++++++++++++
> >  include/linux/pci.h |  1 +
> >  2 files changed, 15 insertions(+)
> >
> > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> > index 81f06e8..6afd507 100644
> > --- a/drivers/pci/pci.c
> > +++ b/drivers/pci/pci.c
> > @@ -137,6 +137,20 @@ void __iomem *pci_ioremap_bar(struct pci_dev *pdev, int bar)
> >                                      pci_resource_len(pdev, bar));
> >  }
> >  EXPORT_SYMBOL_GPL(pci_ioremap_bar);
> > +
> > +void __iomem *pci_ioremap_wc_bar(struct pci_dev *pdev, int bar)
> > +{
> > +       /*
> > +        * Make sure the BAR is actually a memory resource, not an IO resource
> > +        */
> > +       if (!(pci_resource_flags(pdev, bar) & IORESOURCE_MEM)) {
> > +               WARN_ON(1);
> > +               return NULL;
> > +       }
> 
> if (WARN_ON(...))?

Sure, they are equivalent however this follows the same exact style as
pci_ioremap_bar() so if we change this one might as well change the style of
pci_ioremap_bar() as well. Let me know if there is any preference. I personally
don't mind the extra line as it shortens the check.

 Luis
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/