Commit graph

5 commits

Author SHA1 Message Date
Ben Gras
0b79eac642 mmap: accept non-PROT_WRITE MAP_SHARED mappings
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
2014-07-28 17:05:20 +02:00
Ben Gras
aa6ee31737 test74: add mmap-related regression tests
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
2014-07-28 17:05:14 +02:00
Ben Gras
dda632a24f drop the minix_ prefixes for mmap and munmap
also cleanup of various minix-specific changes, cleanup of
mmap-related testing.

Change-Id: I289a4fc50cf8a13df4a6082038d860853a4bd024
2014-03-03 20:47:03 +01:00
Ben Gras
274fdff60c VM bugfix & regression test
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
2014-01-09 18:28:11 +01:00
Ben Gras
49b9165251 vm: mmap support
. 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
2013-05-31 15:42:01 +00:00