kernel-hardening - Re: [PATCH v2] ARM: mm: flip priority of CONFIG_DEBUG

Follow @Openwall on Twitter for new release announcements and other news

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

Message-ID: <20151224001121.GS2793@atomide.com>
Date: Wed, 23 Dec 2015 16:11:22 -0800
From: Tony Lindgren <tony@...mide.com>
To: Nicolas Pitre <nicolas.pitre@...aro.org>
Cc: Laura Abbott <labbott@...hat.com>, Kees Cook <keescook@...omium.org>,
	Russell King <linux@....linux.org.uk>,
	Arnd Bergmann <arnd@...db.de>,
	Ard Biesheuvel <ard.biesheuvel@...aro.org>,
	Catalin Marinas <catalin.marinas@....com>,
	Will Deacon <will.deacon@....com>,
	LKML <linux-kernel@...r.kernel.org>, Linux-MM <linux-mm@...ck.org>,
	kernel-hardening@...ts.openwall.com,
	linux-arm-kernel@...ts.infradead.org,
	Laura Abbott <labbott@...oraproject.org>
Subject: Re: [PATCH v2] ARM: mm: flip priority of CONFIG_DEBUG_RODATA

* Nicolas Pitre <nicolas.pitre@...aro.org> [151223 13:45]:
> On Wed, 23 Dec 2015, Tony Lindgren wrote:
> 
> > Hi,
> > 
> > * Laura Abbott <labbott@...hat.com> [151223 12:31]:
> > > 
> > > Looks like a case similar to Geert's
> > > 
> > >         adr     r7, kick_counter
> > > wait_dll_lock_timed:
> > >         ldr     r4, wait_dll_lock_counter
> > >         add     r4, r4, #1
> > >         str     r4, [r7, #wait_dll_lock_counter - kick_counter]
> > >         ldr     r4, sdrc_dlla_status
> > >         /* Wait 20uS for lock */
> > >         mov     r6, #8
> > > 
> > > 
> > > kick_counter and wait_dll_lock_counter are in the text section which is marked read only.
> > > They need to be moved to the data section along with a few other variables from what I
> > > can tell (maybe those are read only?).
> > 
> > Thanks for looking, yeah so it seem.
> > 
> > > I suspect this is going to be a common issue with suspend/resume code paths since those
> > > are hand written assembly.
> > 
> > Yes I suspect we have quite a few cases like this.
> 
> We fixed a bunch of similar issues where code was located in the .data 
> section for ease of use from assembly code.  See commit b4e61537 and 
> d0776aff for example.

Thanks hey some assembly fun for the holidays :) I also need to check what
all gets relocated to SRAM here.

In any case, seems like the $subject patch is too intrusive for v4.5 at
this point.

Regards,

Tony

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.