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  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, 15 Feb 2008 10:52:33 +0800
From:	"Huang, Ying" <ying.huang@...el.com>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	Andi Kleen <andi@...stfloor.org>, torvalds@...l.org,
	tglx@...utronix.de, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Fix left over EFI cache mapping problems

On Thu, 2008-02-14 at 19:38 +0100, Ingo Molnar wrote:
> * Andi Kleen <andi@...stfloor.org> wrote:
> 
> > > this is indeed a bug (we change the attributes for a larger area 
> > > than needed), but your fix is unclean. Find below a cleaner 
> > > solution.
> > 
> > You're still ignoring the other problem of set_memory_uc() not 
> > handling fixmap and ioremap correctly. [...]
> 
> No, we did not ignore it, and yes, you are wrong.
> 
> One thing that you miss is that the 64-bit EFI runtime has to be marked 
> uncacheable only if it the EFI image attribute signals an uncacheable 
> area:
> 
>                 if (!(md->attribute & EFI_MEMORY_WB))
>                         set_memory_uc(md->virt_addr, md->num_pages);
> 
> and Linux EFI does not support device EFI runtimes. So your observation, 
> while correct for non-RAM 64-bit EFI images, is theoretical at the 
> moment and has no practical relevance.

On my test machine, there is EFI runtime memory area with EFI_MEMORY_UC
attribute. The following is cut from the dmesg:

EFI: mem75: type=4, attr=0xf, range=[0x000000007f4ff000-0x000000007f500000) (0MB)
EFI: mem76: type=11, attr=0x8000000000000001, range=[0x00000000fed1c000-0x00000000fed20000) (0MB)
EFI: mem77: type=11, attr=0x8000000000000001, range=[0x00000000fffb0000-0x00000000fffb4000) (0MB)

Where:

attr is md->attribute,
#define EFI_MEMORY_RUNTIME 0x8000000000000000
#define EFI_MEMORY_UC 0x0000000000000001

But because end_pfn_map contains the above UC memory area, efi_ioremap()
is not used on EFI 64.

Best Regards,
Huang Ying

--
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/

Powered by blists - more mailing lists