I'm very grateful to Charles Forsyth for creating most of Jehanne's kernel
and to 9front's guys for all the code and ideas they freely share.
Here I make their copyrights explicit as they had been erroneusly omitted
or messed up before. Sorry.
This large commit address several issues
- removed 386 directory: Jehanne is 64bit only
- simplified kernel options management
- rewritten boot process
- ported memory related stuff from 9front's 9/pc64
- removed devacpi
- removed old code
- deep refactor of awake syscall
- removed MCACHE support for mount
- fix libc's setjmp/longjmp
This commit introduce a special rendezvous point at (void*)~0 that
cannot be reached by any process, since it's not added to the
rendezvous group.
This turns the rendezvous syscall to a cheap way to block until
either a note or a wakeup from awake(2) occurs.
This new feature is used in libc's sleep: the test qa/kern/fork_chain
has shown that using a stack address as rendezvous point is not safe enougth
for sleep, since two different process forked from the same function can
call sleep with the same base pointer. This lead the wakeup variable in
jehanne_sleep to have the same address on both process.
TODO add a test that show this behaviour in the old code.
Awake can now interrupt several blocking syscalls (even
during note handling).
Among others, it can interrupt await, pread and pwrite.
It cannot interrupt several others for different reasons:
- awake cannot be interrupted by awake;
- syscalls like remove and create can be used for kernel comunication
and it would be hard to know if the effect occurred in the
receiving fs if they were interrupted;
- other syscalls do not need awake since they just provide access
to kernel infos (eg seek or fd2path)
NOTE: awakes registered before a note cannot occur during the note
handling and will be deferred till the next call to noted.
With this commit all functions declared in libc.h have been renamed
with the "jehanne_" prefix. This is done for several reason:
- it removes conflicts during symbol resolution when linking
standard C libraries like newlib or musl
- it allows programs depending on a standard C library to directly
link to a library depending on our non standard libc (eg libsec).
To ease transiction two files are provided:
- sys/include/lib9.h that can be included instead of <libc.h> to use
the old names (via a simple set of macros)
- sys/src/lib/c/lib9.c that can be compiled with a program where the
macro provided by lib9.h are too dumb (see for example rc or grep).
In the kernel port/lib.h has been modified accordingly and some of
the functions it directly provides has been renamed too (eg malloc
in qmalloc.c and print in devcons.c).
Giacomo Tesio