kernel (sys task). The main reason is that these would have to become
cpu local variables on SMP. Once the system task is not a task but a
genuine part of the kernel there is even less reason to have these
extra variables as proc_ptr will already contain all neccessary
information. In addition converting who_e to the process pointer and
back again all the time will be avoided.
Although proc_ptr will contain all important information, accessing it
as a cpu local variable will be fairly expensive, hence the value
would be assigned to some on stack local variable. Therefore it is
better to add the 'caller' argument to the syscall handlers to pass
the value on stack anyway. It also clearly denotes on who's behalf is
the syscall being executed.
This patch also ANSIfies the syscall function headers.
Last but not least, it also fixes a potential bug in virtual_copy_f()
in case the check is disabled. So far the function in case of a
failure could possible reuse an old who_p in case this function had
not been called from the system task.
virtual_copy_f() takes the caller as a parameter too. In case the
checking is disabled, the caller must be NULL and non NULL if it is
enabled as we must be able to suspend the caller.
instance numbers, encoded and decoded using macros in <minix/endpoint.h>.
proc number -> endpoint migration
. proc_nr in the interrupt hook is now an endpoint, proc_nr_e.
. m_source for messages and notifies is now an endpoint, instead of
proc number.
. isokendpt() converts an endpoint to a process number, returns
success (but fails if the process number is out of range, the
process slot is not a living process, or the given endpoint
number does not match the endpoint number in the process slot,
indicating an old process).
. okendpt() is the same as isokendpt(), but panic()s if the conversion
fails. This is mainly used for decoding message.m_source endpoints,
and other endpoint numbers in kernel data structures, which should
always be correct.
. if DEBUG_ENABLE_IPC_WARNINGS is enabled, isokendpt() and okendpt()
get passed the __FILE__ and __LINE__ of the calling lines, and
print messages about what is wrong with the endpoint number
(out of range proc, empty proc, or inconsistent endpoint number),
with the caller, making finding where the conversion failed easy
without having to include code for every call to print where things
went wrong. Sometimes this is harmless (wrong arg to a kernel call),
sometimes it's a fatal internal inconsistency (bogus m_source).
. some process table fields have been appended an _e to indicate it's
become and endpoint.
. process endpoint is stored in p_endpoint, without generation number.
it turns out the kernel never needs the generation number, except
when fork()ing, so it's decoded then.
. kernel calls all take endpoints as arguments, not proc numbers.
the one exception is sys_fork(), which needs to know in which slot
to put the child.
