FWIW, the GNU linker can reorder the kernel on i386-current
with 256MB RAM:
# env LD=ld.bfd /usr/libexec/reorder_kernel
---
relink.log:
(SHA256) /bsd: OK
LD="ld.bfd" LDFLAGS="-g" sh makegap.sh 0xcccccccc gapdummy.o
ld.bfd -T ld.script -X --warn-common -nopie -o newbsd ${SYSTEM_HEAD} vers.o
${OBJS}
text data bss dec hex
11916299 262796 1101824 13280919 caa697
mv newbsd newbsd.gdb
ctfstrip -S -o newbsd newbsd.gdb
rm -f bsd.gdb
mv -f newbsd bsd
install -F -m 700 bsd /bsd && sha256 -h /var/db/kernel.SHA256 /bsd
Kernel has been relinked and is active on next reboot.
SHA256 (/bsd) = 3c9cca9da06acdc92270f6f0e68b57447881a01e3e2584a0086291efb5033ba7
---
On Fri, Apr 10, 2020 at 10:52:37AM -0600, Theo de Raadt wrote:
> I am succesfully relinking kernels on a landisk with 128MB of ram.
>
> I think this conversation is ridiculous:
>
> If a machine is too small, then it is too small. Do I have to paypal
> a $0.05 to some users?
>
> Nick Holland <[email protected]> wrote:
>
> >
> >
> >
> > On 2020-04-10 10:10, Stefan Sperling wrote:
> > > On Fri, Apr 10, 2020 at 09:35:16AM -0400, Nick Holland wrote:
> > >> Question about kernel randomization and relinking...
> > >>
> > >> It seems to take a fair amount of RAM, at least for systems that
> > >> are forced to run i386. And I mean real RAM -- swap doesn't seem
> > >> to cut it.
> > >>
> > >> I discovered that several machines I was intending on using for
> > >> minimal purposes just couldn't complete relinking. So I built a
> > >> VM and started playing with the RAM.
> > >>
> > >> Built with 1G RAM, default was a 1.2G swap, worked fine.
> > >> Reduced to 256MB RAM, Kernel failed to relink. As with my old
> > >> junk.
> > >>
> > >> The magic number seemed to be between 320MB (failed) and 384MB
> > >> (worked) of RAM. Ok, fine.
> > >
> > > FWIW, my soekris net5501 with 256MB of RAM and 512MB swap does manage
> > > to relink a kernel (on 6.6 + syspatches).
> >
> > Whoops. Guess I should have mentioned, that was -current, as of
> > yesterday
> > OpenBSD 6.7-beta (GENERIC.MP) #110: Thu Apr 9 01:20:52 MDT 2020
> > [email protected]:/usr/src/sys/arch/i386/compile/GENERIC.MP
> > real mem = 334970880 (319MB)
> > avail mem = 313077760 (298MB)
> >
> > and probably a couple weeks ago for the real (old) hw.
> >
> > I'm curious if your Soekris can handle 6.7-beta.
> >
> > Nick.
> >
> >
> > >
> > > # ls -l relink.log
> > > -rw-r--r-- 1 root wheel - 507B Apr 10 13:33 relink.log
> > > # cat relink.log
> > > (SHA256) /bsd: OK
> > > LD="ld" LDFLAGS="-g" sh makegap.sh 0xcccccccc gapdummy.o
> > > ld -T ld.script -X --warn-common -nopie -o newbsd ${SYSTEM_HEAD} vers.o
> > > ${OBJS}
> > > text data bss dec hex
> > > 11815507 267748 1101824 13185079 c93037
> > > mv newbsd newbsd.gdb
> > > ctfstrip -S -o newbsd newbsd.gdb
> > > rm -f bsd.gdb
> > > mv -f newbsd bsd
> > > install -F -m 700 bsd /bsd && sha256 -h /var/db/kernel.SHA256 /bsd
> > >
> > > Kernel has been relinked and is active on next reboot.
> > >
> > > SHA256 (/bsd) =
> > > a940ce989d708e5b87a1186ee81bd624066baeabe67b8405b52e4fa2988b565
> > >
> > >
> > > # dislabel -pm wd0
> > > # size offset fstype [fsize bsize cpg]
> > > a: 353.0M 64 4.2BSD 2048 16384 5624 # /
> > > b: 511.1M 722944 swap # none
> > > c: 15280.0M 0 unused
> > > d: 444.8M 1769728 4.2BSD 2048 16384 7116 # /tmp
> > > e: 607.7M 2680576 4.2BSD 2048 16384 9685 # /var
> > > f: 1703.0M 3925216 4.2BSD 2048 16384 12958 # /usr
> > > g: 505.8M 7412896 4.2BSD 2048 16384 8060 #
> > > /usr/X11R6
> > > h: 1632.9M 8448736 4.2BSD 2048 16384 12958 #
> > > /usr/local
> > > i: 1381.2M 11792960 4.2BSD 2048 16384 12958 #
> > > /usr/src
> > > j: 5282.4M 14621632 4.2BSD 2048 16384 12958 #
> > > /usr/obj
> > > k: 2850.9M 25439936 4.2BSD 2048 16384 12958 # /home
> > >
> >
