CVS commit: src/sys/kern

["Maxime Villard" <maxv%netbsd.org@localhost>]

Module Name:    src
Committed By:   maxv
Date:           Wed Jul 20 13:11:58 UTC 2016

Modified Files:
        src/sys/kern: subr_kobj.c

Log Message:
Change the protection of the kernel modules segments once we are done
relocating them. The text is allocated as RWX, and then mprotected to RW.

There is a bug that prevents us from doing RW->RX on amd64 and perhaps
sparc64. On x86, the pmap waits for the page to fault before granting it
the X permission. But in the trap handler, such a page is considered as
belonging to kernel_map, while it actually belongs to module_map. The
kernel then finds out the page is not present in kernel_map, and panics.
In all cases, module_map is non pageable, so even if the trap were handled
properly, it still wouldn't work.

Therefore, there is a small window in which the segment is RWX. But that's
fine enough, for now.


To generate a diff of this commit:
cvs rdiff -u -r1.55 -r1.56 src/sys/kern/subr_kobj.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.