Re: [PATCH] Xen: EFI: Parse DT parameters for Xen specific UEFI

From: Matt Fleming <matt@codeblueprint.co.uk>
To: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	sstabellini@kernel.org, ard.biesheuvel@linaro.org,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	xen-devel@lists.xen.org, stefano@aporeto.com,
	julien.grall@arm.com, linux-efi@vger.kernel.org,
	shannon.zhao@linaro.org, Shannon Zhao <zhaoshenglong@huawei.com>,
	peter.huangpeng@huawei.com,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] Xen: EFI: Parse DT parameters for Xen specific UEFI
Date: Wed, 11 May 2016 13:29:48 +0100	[thread overview]
Message-ID: <20160511122948.GV2839__25636.0253006735$1462969919$gmane$org@codeblueprint.co.uk> (raw)
In-Reply-To: <CANLsYkxUyiUfdjm39SvhKSvmddPLFP3JFAeHpYuxgPyZfexw6w@mail.gmail.com>

On Fri, 06 May, at 09:52:42AM, Mathieu Poirier wrote:
> > +static int __init efi_remap_init(void)
> > +{
> > +       u64 mapsize;
> > +
> > +       pr_info("Remapping and enabling EFI services.\n");
> > +
> > +       mapsize = memmap.map_end - memmap.map;
> > +       memmap.map = (__force void *)ioremap_cache(memmap.phys_map,
> > +                                                  mapsize);
> > +       if (!memmap.map) {
> > +               pr_err("Failed to remap EFI memory map\n");
> > +               return -ENOMEM;
> > +       }
> > +       memmap.map_end = memmap.map + mapsize;
> > +       efi.memmap = &memmap;
> > +
> > +       efi.systab = (__force void *)ioremap_cache(efi_system_table,
> > +                                                  sizeof(efi_system_table_t));
> > +       if (!efi.systab) {
> 
> Is there a reason why memmap.map isn't iounmap() in the error path?
> The original code didn't have it either, hence the question.

I suspect that is a bug.

In reality, if you can't access the EFI System Table because you fail
to map it I would guess you are going to crash very, very quickly
anyhow.

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel