Live Q&A - Demystifying Memory Protection Units (MPUs)
Jean Labrosse - Watch Now - Duration: 27:18
19:01:35 From Leandro Pérez : Great talk Jean Labrosse... I have three questions: 1) You say "Code can execute out of RAM... Susceptible to code injection attacks" Could you explain me this point? 2) I have a task that handle the UART messages logger. I create a queue (Object) that all the other task use for send message to the UART logger. The problem is that the object of the QUEUE that store the message consume much memory, because for example save 256 bytes to the message. If I defined a queue of the 200 elements... the queue use 51.2KB from RAM... What you suggest me to reduce this high consumption? 3) How I can document a RTOS project (a tool) that show the relation between task, priorities, sempahores and mutexes? 19:02:44 From Steve Schwartz-Fenwick : Hello, great talk. What recommendations do you have for using the MPU with C++? Is there any benefit we can get from the MPU given that we need the heap for C++? 19:03:19 From Jay : After your presentation, I checked on our codebase to see if we implemented the MPU, but found that MPU support is spotty for our RTOS with SMP architecture. Is this common? What is the reason? 19:03:34 From Gary to Stephane Boucher(Direct Message) : When are the 2020 talks being pulled off the site? 19:03:53 From Charles Miller : All--a round of applause for Jacob and Stephane. A superb conference, guys! Thanks to all the speakers as well. 19:04:48 From javi : In the process table example you saw us there were many unused regions, is there any reason for that? 19:05:12 From Steve Wheeler : It was a great presentation. Lots of fascinating information. I’m a little unclear on how you determine which tasks get grouped into processes - is it functional or a matter of which regions of processor registers they need to access? Also, I imagine the MPU and privileged mode switches adds overhead. Is it at all significant? 19:05:58 From Gerhard : @javi: In the table are just the values to store in the MPU registers. 19:07:37 From javi : @Gerhard, ok.. and he puts the powermeter task stack in the last region because it is the highest priority MPU region, right? 19:07:57 From metty : In the inter-process communications/data sent by value slide, messages should be small to avoid by-copy overhead. What is the maximum message size for the messages to avoid long time for copying? 19:08:19 From metty : @Jean Labrosse 19:09:32 From Sam : Another great presentation. In the weeds, loved it! Thank you. 19:10:13 From Sam : Jacob and Stephane, THANK YOU. In my view, better than DEFCON. 19:10:32 From Stephane Boucher to Gary(Direct Message) : Thank you Sam! 19:11:20 From Gary to Stephane Boucher(Direct Message) : Stephane I think you meant to send your last message to everyone. Not just me. 19:11:22 From Jay : For more on that exploit, check out last year's presentation: https://www.embeddedonlineconference.com/session/Defending_against_Hackers_Exploit_Mitigations_and_Attacks_on_Arm_Cortex-A_Devices 19:11:40 From Gerhard : @javi: I think so, but I don’t know in which order the MCU evaluates the registers. 19:11:46 From Stephane Boucher to Gary(Direct Message) : @Gary, they will stay available at least until EOC 2022 19:12:06 From Stephane Boucher to Gary(Direct Message) : Gary, they will stay available at least until EOC 2022 19:12:12 From Jose E. : Jean mentioned that not using MPU can make it difficult to certify your product. I wanted to ask if he could ellaborate on that please. Great presentation btw! 19:12:22 From Gary to Stephane Boucher(Direct Message) : Thank you. 19:12:39 From Stephane Boucher to Gary(Direct Message) : @Charles Miller, thank you! 19:13:14 From Stephane Boucher : @Charles Miller, Thank you! 19:13:48 From javi : @Gerhard, thanks for the help. I was curious about why he put the stack in the last region 19:13:52 From Charles Miller : Would a bootloader copied from flash to ram so flash can be updated be a legal case of running from RAM? Would modifying the access "on the fly" be a mitigation? That mod might be the start of a hack...? What to do, what to do... 19:14:12 From Stephane Boucher : The 2020 (& 2021) talks will stay available at least until EOC 2022 19:14:28 From Leandro Pérez : Great Stephane 19:14:47 From Stephane Boucher : Thank you Sam! 19:15:04 From Leandro Pérez to Stephane Boucher(Direct Message) : Is my first time in EOC.... Always be online? 19:15:23 From Michael Kirkhart : The first RTOS I used was uC/OS 19:15:31 From Stephane Boucher to Leandro Pérez(Direct Message) : Probably, I'd say... 19:16:19 From Leandro Pérez to Stephane Boucher(Direct Message) : I hope in the future meet all in real world 19:16:49 From Stephane Boucher to Leandro Pérez(Direct Message) : Maybe one day, we'll organize an hybrid conference 19:17:37 From Charles Miller : I like Enterprise Architect for documentation. A good UML tool. 19:19:23 From Leandro Pérez to Stephane Boucher(Direct Message) : Thanks @Jean 19:19:36 From Leandro Pérez to Stephane Boucher(Direct Message) : I like document all 19:19:50 From Leandro Pérez to Stephane Boucher(Direct Message) : Thanks 19:21:15 From Leandro Pérez : Thanks @Jean I like document all Thanks 19:22:49 From Dave Nadler : MPUs haven't been available all that long.... 19:23:40 From Jay : My impression was that it was related to SMP 19:24:03 From afwaanquadri : Thanks Jean! 19:24:59 From Rocco Brandi : one commercial RTOS that uses MPU extensively is Integrity from Green Hills https://ghs.com/products/rtos/integrity.html 19:25:16 From javi : Great, thanks Jean 19:27:42 From Steve Wheeler : Thank you. That answers my question. 19:29:50 From Stefan Petersen : You talk about processes consists of several task. Can you elaborate on your definition on processes and task? 19:29:57 From metty : Thanks @Jean Labrosse, @Beningo 19:30:24 From Bob Dowling : Thanks, Stephane & Jacob! 19:30:37 From Steve Wheeler : Jacob, will recordings of the Q&A sessions be available? 19:30:51 From afwaanquadri : Thanks Jacob and Stephane. 19:30:54 From Nikola Jovanovic : great job guys, thank you! 19:30:56 From Konstantin : Thanks, great job! 19:31:46 From Gary : HUGE thanks to Jacob and Stephane. You have both done a tremendous job. I hope to be back next year 19:32:06 From Stephane Boucher : Yes, all Q&A have been uploaded and are now available 'on-demand', other than this one that you are in right now! 19:32:26 From Stefan Petersen : Thanks! Very nice talk and explanation! 19:32:40 From afwaanquadri : I will be looking forward to next year's conference. 19:32:46 From Rob Meades : Thank you Jean, I was actually implementing MPU support on a new processor today and pondering how far I should look into proper RTOS support; you have answered EVERYTHING! 19:32:49 From metty : Thanks, Stephane & Jacob! 19:32:53 From javi : Does the MPU influence ianyhow in the debugging? 19:33:08 From David Kanceruk : Thanks Jean, Jacob and Stephane. Great conclusion to a very informative conference. 19:34:07 From Keith J : Thanks for doing this Stephane and Jacob. Love the accessibility of the online conference format... miss the personal interaction with attendees though. But nothing you can do there. 19:35:04 From Will Hsiung : Thanks Jean for the presentation and to Jacob and Stephane for the online conference! 19:35:18 From Stephane Boucher : I recognize many names here that showed up to many of the Q&A sessions. Thank you to you guys, you made that conference very interesting and vibrant! 19:35:41 From javi : Thanks, great answer 19:35:55 From Keith J : Thanks for taking the time Jean!!! 19:36:04 From Erwin : Thanks to all speakers and the organizers! You did a great job! So much useful information. Like a perfectly designed embedded System. 19:36:14 From Sam : thank you. 19:36:47 From Raul Pando : Thanks a lot, I thoroughly enjoyed the conference. Can't wait until next year :) 19:36:58 From Leandro Pérez : Thanks @Jacob, @Stephane and all the conferences.... Was a superb event!!! I will be in the event on 2022 19:37:03 From Rob Meades : Thank you Jacob and Stephane! 19:37:08 From Gerhard : Thanks! 19:37:10 From dayolawa : Thank you! 19:37:12 From Bruce Lueckenhoff : Thanks to Jacob, Stephane, and all the speakers! 19:37:32 From Steve Wheeler : I’ve really enjoyed the conference. And it’s inexpensive enough that I can afford it now that I’m retired :-) Looking forward to next year! 19:37:44 From javi : thanks, this conference has exceeded my expectations. Great job 19:38:23 From javi : Where do we go now for the beers? 19:38:48 From Dave Nadler : JJacob, do you have a beer Zoom? 19:38:52 From Yuriy Kozhynov : Many-many thanks!!! 19:38:56 From Rostifer : Thanks to all the presenters and organizers! 19:38:59 From Sam : This was my first EOC. Better than DEFCON that I attended. More in depth. 19:39:19 From Leandro Pérez : lol 19:39:54 From Leandro Pérez : Regards from Latam… It was a great resource 19:39:56 From Jay : thanks!! 19:39:58 From Rocco Brandi : thanks! 19:39:58 From Keith J : To a better 2021 all 19:40:01 From Jose E. : thanks!