coredump: add VM_NODUMP, MADV_NODUMP, MADV_CLEAR_NODUMP

Since we no longer need the VM_ALWAYSDUMP flag, let's use the freed bit
for 'VM_NODUMP' flag.  The idea is is to add a new madvise() flag:
MADV_DONTDUMP, which can be set by applications to specifically request
memory regions which should not dump core.

The specific application I have in mind is qemu: we can add a flag there
that wouldn't dump all of guest memory when qemu dumps core.  This flag
might also be useful for security sensitive apps that want to absolutely
make sure that parts of memory are not dumped.  To clear the flag use:
MADV_DODUMP.

[[email protected]: s/MADV_NODUMP/MADV_DONTDUMP/, s/MADV_CLEAR_NODUMP/MADV_DODUMP/, per Roland]
[[email protected]: fix up the architectures which broke]
Signed-off-by: Jason Baron <[email protected]>
Acked-by: Roland McGrath <[email protected]>
Cc: Chris Metcalf <[email protected]>
Cc: Avi Kivity <[email protected]>
Cc: Ralf Baechle <[email protected]>
Cc: Richard Henderson <[email protected]>
Cc: Ivan Kokshaysky <[email protected]>
Cc: Matt Turner <[email protected]>
Cc: "James E.J. Bottomley" <[email protected]>
Cc: Helge Deller <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions