linux-kernel - Re: [PATCH v3 2/3] hwmon: xgene: Add hwmon driver

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]

Date:   Fri, 09 Sep 2016 17:38:15 +0200
From:   Arnd Bergmann <arnd@...db.de>
To:     Guenter Roeck <linux@...ck-us.net>
Cc:     Hoan Tran <hotran@....com>, Jean Delvare <jdelvare@...e.com>,
        Jonathan Corbet <corbet@....net>,
        Rob Herring <robh+dt@...nel.org>,
        Jassi Brar <jassisinghbrar@...il.com>,
        Ashwin Chaugule <ashwin.chaugule@...aro.org>,
        Duc Dang <dhdang@....com>, lho@....com,
        linux-hwmon@...r.kernel.org, linux-doc@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        devicetree@...r.kernel.org
Subject: Re: [PATCH v3 2/3] hwmon: xgene: Add hwmon driver

On Wednesday, September 7, 2016 3:37:05 PM CEST Guenter Roeck wrote:
> On Wed, Sep 07, 2016 at 11:41:44PM +0200, Arnd Bergmann wrote:
> > On Thursday, July 21, 2016 1:55:56 PM CEST Hoan Tran wrote:
> > > +               ctx->comm_base_addr = cppc_ss->base_address;
> > > +               if (ctx->comm_base_addr) {
> > > +                       ctx->pcc_comm_addr =
> > > +                                       acpi_os_ioremap(ctx->comm_base_addr,
> > > +                                                       cppc_ss->length);
> > > 
> > 
> > This causes the arm64 allmodconfig build to fail now, according to
> > kernelci:
> > 
> >       1  ERROR: "memblock_is_memory" [drivers/hwmon/xgene-hwmon.ko] undefined!
> > 
> > Should this perhaps call ioremap() or memremap() instead?
> > 
> Hmmm ... almost sounds to me like blaming the messenger. e7cd190385d1 ("arm64:
> mark reserved memblock regions explicitly in iomem") starts using a function
> in acpi_os_ioremap() which is not exported. On top of that, memblock_is_memory()
> is declared as __init_memblock, which makes me really uncomfortable.
> If acpi_os_ioremap() must not be used by modules, and possibly only during
> early (?) initialization, maybe its declaration should state those limitations ?

I think there is more wrong with it, the driver also accesses a shared
memory area with kernel pointers using readl_relaxed/writel_relaxed,
which are only valid on MMIO registers.

I've prepared a patch, please have a look at the follow-up email.

	Arnd