KERNEL CHANGES:
- The kernel only knows about privileges of kernel tasks and the root system
process (now RS).
- Kernel tasks and the root system process are the only processes that are made
schedulable by the kernel at startup. All the other processes in the boot image
don't get their privileges set at startup and are inhibited from running by the
RTS_NO_PRIV flag.
- Removed the assumption on the ordering of processes in the boot image table.
System processes can now appear in any order in the boot image table.
- Privilege ids can now be assigned both statically or dynamically. The kernel
assigns static privilege ids to kernel tasks and the root system process. Each
id is directly derived from the process number.
- User processes now all share the static privilege id of the root user
process (now INIT).
- sys_privctl split: we have more calls now to let RS set privileges for system
processes. SYS_PRIV_ALLOW / SYS_PRIV_DISALLOW are only used to flip the
RTS_NO_PRIV flag and allow / disallow a process from running. SYS_PRIV_SET_SYS /
SYS_PRIV_SET_USER are used to set privileges for a system / user process.
- boot image table flags split: PROC_FULLVM is the only flag that has been
moved out of the privilege flags and is still maintained in the boot image
table. All the other privilege flags are out of the kernel now.
RS CHANGES:
- RS is the only user-space process who gets to run right after in-kernel
startup.
- RS uses the boot image table from the kernel and three additional boot image
info table (priv table, sys table, dev table) to complete the initialization
of the system.
- RS checks that the entries in the priv table match the entries in the boot
image table to make sure that every process in the boot image gets schedulable.
- RS only uses static privilege ids to set privileges for system services in
the boot image.
- RS includes basic memory management support to allocate the boot image buffer
dynamically during initialization. The buffer shall contain the executable
image of all the system services we would like to restart after a crash.
- First step towards decoupling between resource provisioning and resource
requirements in RS: RS must know what resources it needs to restart a process
and what resources it has currently available. This is useful to tradeoff
reliability and resource consumption. When required resources are missing, the
process cannot be restarted. In that case, in the future, a system flag will
tell RS what to do. For example, if CORE_PROC is set, RS should trigger a
system-wide panic because the system can no longer function correctly without
a core system process.
PM CHANGES:
- The process tree built at initialization time is changed to have INIT as root
with pid 0, RS child of INIT and all the system services children of RS. This
is required to make RS in control of all the system services.
- PM no longer registers labels for system services in the boot image. This is
now part of RS's initialization process.
Kernel:
o Remove s_ipc_sendrec, instead using s_ipc_to for all send primitives
o Centralize s_ipc_to bit manipulation,
- disallowing assignment of bits pointing to unused priv structs;
- preventing send-to-self by not setting bit for own priv struct;
- preserving send mask matrix symmetry in all cases
o Add IPC send mask checks to SENDA, which were missing entirely somehow
o Slightly improve IPC stats accounting for SENDA
o Remove SYSTEM from user processes' send mask
o Half-fix the dependency between boot image order and process numbers,
- correcting the table order of the boot processes;
- documenting the order requirement needed for proper send masks;
- warning at boot time if the order is violated
RS:
o Add support in /etc/drivers.conf for servers that talk to user processes,
- disallowing IPC to user processes if no "ipc" field is present
- adding a special "USER" label to explicitly allow IPC to user processes
o Always apply IPC masks when specified; remove -i flag from service(8)
o Use kernel send mask symmetry to delay adding IPC permissions for labels
that do not exist yet, adding them to that label's process upon creation
o Add VM to ipc permissions list for rtl8139 and fxp in drivers.conf
Left to future fixes:
o Removal of the table order vs process numbers dependency altogether,
possibly using per-process send list structures as used for SYSTEM calls
o Proper assignment of send masks to boot processes;
some of the assigned (~0) masks are much wider than necessary
o Proper assignment of IPC send masks for many more servers in drivers.conf
o Removal of the debugging warning about the now legitimate case where RS's
add_forward_ipc cannot find the IPC destination's label yet
mainly in the kernel and headers. This split based on work by
Ingmar Alting <iaalting@cs.vu.nl> done for his Minix PowerPC architecture
port.
. kernel does not program the interrupt controller directly, do any
other architecture-dependent operations, or contain assembly any more,
but uses architecture-dependent functions in arch/$(ARCH)/.
. architecture-dependent constants and types defined in arch/$(ARCH)/include.
. <ibm/portio.h> moved to <minix/portio.h>, as they have become, for now,
architecture-independent functions.
. int86, sdevio, readbios, and iopenable are now i386-specific kernel calls
and live in arch/i386/do_* now.
. i386 arch now supports even less 86 code; e.g. mpx86.s and klib86.s have
gone, and 'machine.protected' is gone (and always taken to be 1 in i386).
If 86 support is to return, it should be a new architecture.
. prototypes for the architecture-dependent functions defined in
kernel/arch/$(ARCH)/*.c but used in kernel/ are in kernel/proto.h
. /etc/make.conf included in makefiles and shell scripts that need to
know the building architecture; it defines ARCH=<arch>, currently only
i386.
. some basic per-architecture build support outside of the kernel (lib)
. in clock.c, only dequeue a process if it was ready
. fixes for new include files
files deleted:
. mpx/klib.s - only for choosing between mpx/klib86 and -386
. klib86.s - only for 86
i386-specific files files moved (or arch-dependent stuff moved) to arch/i386/:
. mpx386.s (entry point)
. klib386.s
. sconst.h
. exception.c
. protect.c
. protect.h
. i8269.c
any number of kernel calls.
Allowed kernel calls are stored in table.c for every image process as a
variably-sized array of allowed calls. This is used to fill the bitmap
of size determined at compile time by the number of kernel calls. This
filling is done by main.c. There is a special call called SYS_ALL_CALLS
which fills the bitmap of allowed calls completely, if that is the only
entry in the array.
enforced. If a call is denied, this will be kprinted. Please report any such
errors, so that I can adjust the mask before returning errors instead of
warnings.
Wrote CMOS driver. All CMOS code from FS has been removed. Currently the
driver only supports get time calls. Set time is left out as an exercise
for the book readers ... startup scripts were updated because the CMOS driver
is needed early on. (IS got same treatment.) Don't forget to run MAKEDEV cmos
in /dev/, otherwise the driver cannot be loaded.
to provide an index (0 .. 31) that is passed in the HARD_INT message when an
interrupt occurs. The NOTIFY_ARG field contains a bitmap with all indexes for
which an interrupt occured.
- reinstalled priority changing, now in sched() and unready()
- reinstalled check on message buffer in sys_call()
- reinstalled check in send masks in sys_call()
- changed do_fork() to get new privilege structure for SYS_PROCs
- removed some processes from boot image---will be dynamically started later
- fixed bug that caused IDLE to panic (irq hook inconsistency);
- kprintf() now accepts multiple arguments; moved to utility.c;
- prepare_shutdown() signals system processes with SIGKSTOP;
- phys_fill() renamed to phys_memset(), argument order changed;
- kmemset() removed in favor of phys_kmemset();
- kstrncpy() removed in favor of phys_copy();
- katoi, kstrncmp replaced by normal library procedure again;
- rm_irq_handler() interface changed (simply pass hook pointer);
that passes signal map along. This mechanisms is also used for nonuser signals
like SIGKMESS, SIGKSTOP, SIGKSIG.
Revised comments of many system call handlers. Renamed setpriority to nice.
