Re: proposal for meltdown-workaround with low overhead

2018-01-05 Thread Alexander Kleinsorge
together if the read attempt in step 2 is itself only speculative)" Thanks for further comments, Alexander Am 2018-01-05 00:09, schrieb Tony Luck: On Thu, Jan 4, 2018 at 11:45 AM, Alexander Kleinsorge wrote: As Meltdown-Issue depends on allowing to cause many exceptions (usually :

proposal for meltdown-workaround with low overhead

2018-01-04 Thread Alexander Kleinsorge
Hi all, This is my first post here and I hope it is fine. I will subscribe tomorrow to this list, so please take me in CC for answers now. As Meltdown-Issue depends on allowing to cause many exceptions (usually : accessing an invalid address), we could restrict this misusage easy. My rough

Aw: Re: new module to check constant memory for corruption

2014-04-14 Thread Alexander . Kleinsorge
Hi Andi, I would like to ask for your help. Is there a central kernel function that enables/disables write-protection for kernel memory? I only know the place, where its write protected at booting for x86/x64. If there is one place, it would be much easier, as to hook into many places (e.g. ftra

Aw: Re: Re: new module to check constant memory for corruption

2014-04-13 Thread Alexander . Kleinsorge
of a message to majord...@vger.kernel.org > More majordomo info at > http://vger.kernel.org/majordomo-info.html[http://vger.kernel.org/majordomo-info.html] > Please read the FAQ at http://www.tux.org/lkml/[http://www.tux.org/lkml/] -- Thanks, //richard/* ramcheck.c - checks predefined

Aw: Re: Re: new module to check constant memory for corruption

2014-04-13 Thread Alexander . Kleinsorge
Hi Andi,   1. I build in a check if ftrace is enabled. (like: cat /debug/tracing/tracing_enabled != 1) 2. Main goal is to detect: real ram errors (non crc systems = normal pc). This happens more often than you think: DRAM Errors in the Wild: A Large-Scale Field Study, Mai 2009 (http://www.cs.to

Aw: Re: new module to check constant memory for corruption

2014-04-13 Thread Alexander . Kleinsorge
Hi Andi, the module considers only the adress range between: kallsyms_lookup_name("_text") .. kallsyms_lookup_name("__end_rodata"). this range has a typical size of 10..20 mb (depending on kernel-version and arch).  see files: linux-3.*\arch\x86\mm\init_32.c + init_64.c function: void mark_rodat

new module to check constant memory for corruption

2014-04-12 Thread Alexander . Kleinsorge
st other arch. see: ramcheck.tgz ramcheck.tgz Description: Binary data /* ramcheck.c - checks predefined kernel memory region * * KernelRamCheck by * * Copyright 2014 Alexander Kleinsorge * Copyright 2014 Benjamin Schroedl * * This program is free software; you can redistribute it and/or modify