Currently we don't accept writable file mmap()s, as there is no
system in place to guarantee dirty buffers would make it back to
disk. But we can actually accept MAP_SHARED for PROT_READ mappings,
meaning the ranges aren't writable at all (and no private copy is
made as with MAP_PRIVATE), as it turns out a fairly large class of
usage.
. fail writable MAP_SHARED mappings at runtime
. reduces some minix-specific patches
. lets binutils gold build on minix without further patching
Change-Id: If2896c0a555328ac5b324afa706063fc6d86519e
tests many complex system/process memory interaction cases.
has to run as root so it can flush the FS cache; needed to
force FS cache misses for unmapped pages.
See the comment in test74.c for a full description of what the tested
cases are.
also re-enable filemap on arm
The bug in the offset correction code for the 'shrink region from
below' case can easily case an assert(foundregion->offset == offset)
to trigger (if the blocks are touched afterwards, e.g. on fork())
as the offsets become wrong. This commit is a fix & regression test.
Change-Id: I28ed403e3891362a2dea674a49e786d3450d2983
. test74 for mmap functionality
. vm: add a mem_file memory type that specifies an mmap()ped
memory range, backed by a file
. add fdref, an object that keeps track of FD references within
VM per process and so knows how to de-duplicate the use of FD's
by various mmap()ped ranges; there can be many more than there can
be FD's
. turned off for now, enable with 'filemap=1' as boot option
Change-Id: I640b1126cdaa522a0560301cf6732b7661555672
