linux-kernel - Re: [v4,1/2] arch/powerpc: Implement Optprobes

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: <3vN27w1vFGz9s74@ozlabs.org>
Date:   Tue, 14 Feb 2017 23:40:28 +1100 (AEDT)
From:   Michael Ellerman <patch-notifications@...erman.id.au>
To:     Anju T <anju@...ux.vnet.ibm.com>, linux-kernel@...r.kernel.org,
        linuxppc-dev@...ts.ozlabs.org
Cc:     ananth@...ibm.com, mahesh@...ux.vnet.ibm.com, paulus@...ba.org,
        mhiramat@...nel.org, naveen.n.rao@...ux.vnet.ibm.com,
        hemant@...ux.vnet.ibm.com, srikar@...ux.vnet.ibm.com
Subject: Re: [v4,1/2] arch/powerpc: Implement Optprobes

On Wed, 2017-02-08 at 09:50:51 UTC, Anju T wrote:
> Current infrastructure of kprobe uses the unconditional trap instruction
> to probe a running kernel. Optprobe allows kprobe to replace the trap with
> a branch instruction to a detour buffer. Detour buffer contains instructions
> to create an in memory pt_regs. Detour buffer also has a call to
> optimized_callback() which in turn call the pre_handler().
> After the execution of the pre-handler, a call is made for instruction
> emulation. The NIP is determined in advanced through dummy instruction
> emulation and a branch instruction is created to the NIP at the end of
> the trampoline.
> 
> To address the limitation of branch instruction in POWER architecture,
> detour buffer slot is allocated from a reserved area. For the time being,
> 64KB is reserved in memory for this purpose.
> 
> Instructions which can be emulated using analyse_instr() are the candidates
> for optimization. Before optimization ensure that the address range
> between the detour buffer allocated and the instruction being probed
> is within +/- 32MB.
> 
> Signed-off-by: Anju T Sudhakar <anju@...ux.vnet.ibm.com>
> Signed-off-by: Naveen N. Rao <naveen.n.rao@...ux.vnet.ibm.com>
> Acked-by: Masami Hiramatsu <mhiramat@...nel.org>

Series applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/51c9c0843993528bffc920c54c2121

cheers