On Thu, Apr 21, 2022 at 08:52:59AM +0200, Geert Uytterhoeven wrote: > On Thu, Apr 21, 2022 at 1:53 AM Greg Ungerer <gerg@xxxxxxxxxxxxxx> wrote: > > On 21/4/22 00:58, Eric W. Biederman wrote: > > > In a recent discussion[1] it was reported that the binfmt_flat library > > > support was only ever used on m68k and even on m68k has not been used > > > in a very long time. > > > > > > The structure of binfmt_flat is different from all of the other binfmt > > > implementations becasue of this shared library support and it made > > > life and code review more effort when I refactored the code in fs/exec.c. > > > > > > Since in practice the code is dead remove the binfmt_flat shared libarary > > > support and make maintenance of the code easier. > > > > > > [1] https://lkml.kernel.org/r/81788b56-5b15-7308-38c7-c7f2502c4e15@xxxxxxxxxxxxxx > > > Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> > > > --- > > > > > > Can the binfmt_flat folks please verify that the shared library support > > > really isn't used? > > > > I can definitely confirm I don't use it on m68k. And I don't know of > > anyone that has used it in many years. > > > > > > > Was binfmt_flat being enabled on arm and sh the mistake it looks like? > > I think the question was intended to be > > Was *binfmt_flat_shared_flat* being enabled on arm and sh the > mistake it looks like? Early in my work on j2, I tried to research the history of shared flat support on sh, and it turned out the mainline tooling never even supported it, and the out-of-line tooling I eventually found was using all sorts of wrong conditionals for how it did the linking and elf2flt conversion, e.g. mere presence of any PIC-like relocation in any file made it assume the whole program was PIC-compatible. There's no way that stuf was ever used in any meaningful way. It just didn't work. Quickly dropped that and got plain ELF (no shared text/xip, but no worse than the existing flat support) working, and soon after, FDPIC. The whole binfmt_flat ecosystem is a mess with no good reason to exist. Rich
