Hi Linus, > Including Alexander Sverdlin, Lukasz Majewski and Jonas > Jensen here, they may or may not be able to share some of > their industrial IoT experience. (Contract terms with vendors > may make it necessary to stay silent sometimes.) Thank you for putting me on CC. > > On Mon, Sep 10, 2018 at 11:41 PM Arnd Bergmann wrote: > > On Mon, Sep 10, 2018 at 5:35 PM Linus Walleij > > wrote: > > > > My ARMv4 is another example, but I can point at new devices > > > beging deployed as we speak, using that ISA, even though it is > > > from 1999. So it has many active users (and maintainers). > > > > Note that even though gcc is dropping ARMv4 support from new > > compilers, you can still use old toolchains, and there are tricks to > > make ARMv4T binary code work on ARMv4. However, if gcc > > ever stops supporting ARMv4T, this becomes a problem. My guess > > is that will take another 10 years though, and we might have > > removed some or all of the individual ARMv4 platforms by then. > > ARMv4 is becoming a trouble, not that it is hard to maintain, > actually we're on top of things there. The problem is that among > the FA526 systems from Faraday and the ARMv4T in EP93xx > there are very serious IoT deployments that have been going > on for soon 15 years and continuing. The ARMv4T shall be supported. The 15 years may be a bare minimum for some "heavy duty/industrial" systems... It may happen that the same HW (certified already) will be used for 30+ years (with the SW BSP replaced a few times). > > New MOXA ART ARMv4 FA526 systems are being deployed > in buildings across the planet as we speak. They just replaced > one in the office block where I sit, that is how I got to know. > > These are mostly for ventilation and > similar systems but also heavy duty from Liebherr controlling > unspecified hydraulic systems. The ventilation systems are > definately Internet-connected, I don't know about the others. The "unspecified hydraulic systems" do have a way to update the SW (which is already done). > > These pose an increasing security threat, and for that reason > I personally feel it is irresponsible to remove the option to > create new kernels and upgrade these devices. Frankly speaking the possibility to have the new kernel in a relatively easy (and cheap) way was a strong motivator to add support to mainline. > > I think for depreciation one has to be aware that some archs > used in IoT deployments have life cycles of 20-30 or more years, > whereas some tablet or handset SoCs may be something like > 5 years maximum before maintainers get annoyed that you > even use them. > > Sometimes I get the feeling that people focused on desktops > or servers suffer from velocitate (speed blindness) and think > everybody is like them. (Well don't we all.) I do must agree here. In general ARM9 (v4T) will stay with us for a long, long time. In the kernel community we pose a lot of attention to security (for example the prompt reaction on meltdown/spectre), but in the same time we tend to forget about the "long lived" devices and force their maintainers to use 2.6.x kernels..... (or even 2.4.x). > > With all the hoopla about IoT in the business right now since > a year or two back, the question of their extremely long life > cycle and effect on development has not really been > considered AFAICT those are some of the most important > systems to keep maintained. +1 > > Yours, > Linus Walleij Best regards, Lukasz Majewski -- DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd@denx.de