linux-user: provide fallback pgd_find_hole for bare chroots
When running QEMU out of a chroot environment we may not have access
to /proc/self/maps. As there is no other "official" way to introspect
our memory map we need to fall back to the original technique of
repeatedly trying to mmap an address range until we find one that
works.
Fortunately it's not quite as ugly as the original code given we
already re-factored the complications of dealing with the
ARM_COMMPAGE. We do make an attempt to skip over brk() which is about
the only concrete piece of information we have about the address map
at this moment.
Fixes:
ee9474303
Reported-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <
20200605154929.26910-12-alex.bennee@linaro.org>