- use PAGE_RSRV bit (originally only for blinkenlights),
rather than PAGE_V bit, to indicate that a virtual address
page has been reserved — this should allow a program to
create & reserve inaccessible "guard pages"
- mark page table entries for non-code pages with PAGE_XD bit,
which should be supported on (circa) post-2004 x86-64 CPUs
- correctly check that virtual region we want to use is
unmapped, rather than accidentally clobbering existing pages
- avoid placing mmap'd memory at null virtual address
This change fixes#496 where ASAN spotted a race condition that could
happen in multithreaded programs, with more than OPEN_MAX descriptors
when using ZipOS or Windows NT, which require tracking open file info
and this change fixes that table so it never relocates, thus allowing
us to continue to enjoy the benefits of avoiding locks while reading.
2022-09-09 16:54:28 -07:00
Renamed from libc/calls/directmap-metal.c (Browse further)
