Date: Tue, 16 Apr 2019 08:26:39 -0700 From: Conrad Meyer <cem@freebsd.org> To: Justin Hibbits <chmeeedalf@gmail.com> Cc: src-committers <src-committers@freebsd.org>, svn-src-all <svn-src-all@freebsd.org>, svn-src-head <svn-src-head@freebsd.org> Subject: Re: svn commit: r346250 - in head: share/man/man4 share/man/man9 sys/dev/random sys/kern sys/libkern sys/sys Message-ID: <CAG6CVpX0TtO48UZU0y7p_H5oQE35kyUQnJi8EWViTxiYphALeg@mail.gmail.com> In-Reply-To: <20190416092402.4288bc90@titan.knownspace> References: <201904151840.x3FIeaEQ009242@repo.freebsd.org> <CAPyFy2D9NQQKwVx5MhCfasQ82x7C9s6mj5kXuDE1oogrQeoJ5A@mail.gmail.com> <CAHSQbTAfwYcLenBxg4ZB13P03S%2BTYEM1-xy3BYsSWJ49hBWLZA@mail.gmail.com> <CAG6CVpXwOhSpmCT1SShvEOZAdjbQSk5xSzk%2BLk8c5fMpnhSKQw@mail.gmail.com> <20190416092402.4288bc90@titan.knownspace>
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On Tue, Apr 16, 2019 at 7:24 AM Justin Hibbits <chmeeedalf@gmail.com> wrote: > > Hi Conrad, > ... > [Power] does use bsdinstall to install. How is entropy loaded at startup, > which causes the problem noted in github? There are a couple very early load sources. loader(8) will load early-boot entropy from /boot/entropy and pass it to the kernel as a fake module (entropy_cache_load in loader.conf(5)), similar to cpu_microcode early load. The fallback option is random(4) itself groping into the filesystem during early auto-conf (SI_SUB_RANDOM:SI_ORDER_FOURTH, IIRC) to access /boot/entropy directly. > If it's loaded before > filesystems get mounted, that could be a problem for us, because /boot > is on a different filesystem (msdosfs, to be read by petitboot). > Petitboot also does not have a way to preload modules, so all we have > at startup, until spawning init, is the kernel. Yes, that seems potentially problematic. Can the Power kernel access the non-msdosfs root filesystem? Let's follow-up offline about PPC-specific early entropy seeding. I would much prefer we figure out a way to provide early entropy to Power than disabling or crippling every early random consumer on the arch. Do you know what the Linux folks do? On Power with darn, we could probably just spin in SI_ORDER_FOURTH until we have enough darn output to seed random. Similar for x86 CI images, I guess; though they do not have the loader problem, some people have non-bsdinstall installation methods. Thanks, Conrad
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