On Mon, Nov 17, 2003 at 01:54:55PM +0100, Gerard Milmeister wrote:
Some software, among them clisp, scm and mit-scheme don't work
with FC1. One problem seems to be that on FC1 stack and malloced memory
is no longer executable, at least not without using mprotect.
Interpreters and compilers like the above commonly allocate a piece of
memory and fill it with executable code. I am sure they can be adapted
to work on FC1, but I would have preferred that the FC1 kernel would
behave in the same way as the RH9 one. Is there any way to disable this
behaviour. Trying to get the problem fixed by the upstream developers
will probably take a long time, and it seems that other Linux distros
don't show this problem...
If they need executable stack in a way which is not known to the compiler,
the programmer has to tell it to the toolchain.
If a program say takes address of a nested function, GCC knows it needs
executable stack and arranges things automatically.
Otherwise, either an object file can be marked as needing executable
stack (with -Wa,--execstack; at least one such object will make the whole
shared library or binary requiring executable stack), or during link
time with -Wl,-z,execstack or after it using execstack(8) utility.
The defaults are such that programs and/or libraries compiled/linked
on <= RHL9 are always assumed to potentially require executable stack,
but if you build a new program on FC1, you really need to tell the toolchain