linux-kernel - Re: [Xen-devel] [PATCH 3/3] xen: use correct type for physical addresses

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: <54AFDE2B0200007800053248@mail.emea.novell.com>
Date:	Fri, 09 Jan 2015 12:56:59 +0000
From:	"Jan Beulich" <JBeulich@...e.com>
To:	"David Vrabel" <david.vrabel@...rix.com>,
	"Juergen Gross" <JGross@...e.com>
Cc:	"xen-devel" <xen-devel@...ts.xenproject.org>,
	<boris.ostrovsky@...cle.com>, <linux-kernel@...r.kernel.org>
Subject: Re: [Xen-devel] [PATCH 3/3] xen: use correct type for physical
 addresses

>>> On 09.01.15 at 13:51, <david.vrabel@...rix.com> wrote:
> On 09/01/15 09:57, Jan Beulich wrote:
>>>>> On 08.01.15 at 18:01, <JGross@...e.com> wrote:
>>> @@ -284,7 +286,7 @@ static void __init xen_update_mem_tables(unsigned long pfn, unsigned long mfn)
>>>  	}
>>>  
>>>  	/* Update kernel mapping, but not for highmem. */
>>> -	if ((pfn << PAGE_SHIFT) >= __pa(high_memory))
>>> +	if (PFN_PHYS(pfn) >= (u64)(__pa(high_memory)))
>> 
>> I don't think you really need the cast on the right side - __pa()
>> should be returning a value of suitable type (and unsigned long
>> would be sufficient for anything up to and including high_memory).
> 
> I'd prefer:
> 
>     if (pfn >= PFN_DOWN(__pa(high_memory))

Even better indeed. Just one more point: Strictly speaking
__pa(high_memory) is invalid, as __pa() is defined for low
memory only. Hence perhaps PFN_UP(__pa(high_memory - 1))?

Jan

--
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/