linux-kernel - Re: [RFC 1/3] x86: Add this_cpu_sp0() to read sp0 for the current cpu

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 for Android: free password hash cracker in your pocket

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

Date:	Wed, 4 Mar 2015 09:02:10 +0100
From:	Ingo Molnar <mingo@...nel.org>
To:	Andy Lutomirski <luto@...capital.net>
Cc:	x86@...nel.org, linux-kernel@...r.kernel.org,
	Borislav Petkov <bp@...en8.de>,
	Oleg Nesterov <oleg@...hat.com>,
	Denys Vlasenko <dvlasenk@...hat.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [RFC 1/3] x86: Add this_cpu_sp0() to read sp0 for the current cpu


* Andy Lutomirski <luto@...capital.net> wrote:

> We currently store references to the top of the kernel stack in 
> multiple places: kernel_stack (with an offset) and 
> init_tss.x86_tss.sp0 (no offset).  The latter is defined by hardware 
> and is a clean canonical way to find the top of the stack.  Add an

Btw., 'per_cpu(init_tss)' is a somewhat misleading name these days, as 
there's nothing 'init' about it anymore - we load it during CPU init 
and then manually maintain its contents. A better name would be 
'current_tss' - referring to both the current CPU and the current 
task?

> This needs minor paravirt tweaks to ensure that On native, sp0

nit: s/On/on/

> defines the top of the kernel stack.  On Xen and lguest, the 
> hypervisor tracks it, but we want to start reading sp0 in the 
> kernel.  Fixing this is simple: just update our local copy of sp0 as 
> well as the hypervisor's copy on task switches.

Thanks,

	Ingo
--
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/