Squashed commit of the following:
configs/: The few configurations that formerly set CONFIG_NFILE_DESCRIPTORS=0 should not default, rather they should set the number of descriptors to 3.
fs/: Remove all conditional logic based on CONFIG_NFILE_DESCRIPTORS == 0
tools/: Tools updates for changes to usage of CONFIG_NFILE_DESCRIPTORS.
syscall/: Remove all conditional logic based on CONFIG_NFILE_DESCRIPTORS == 0
libs/: Remove all conditional logic based on CONFIG_NFILE_DESCRIPTORS == 0
include/: Remove all conditional logic based on CONFIG_NFILE_DESCRIPTORS == 0
drivers/: Remove all conditional logic based on CONFIG_NFILE_DESCRIPTORS == 0
Documentation/: Remove all references to CONFIG_NFILE_DESCRIPTORS == 0
binfmt/: Remove all conditional logic based on CONFIG_NFILE_DESCRIPTORS == 0
arch/: Remove all conditional logic based on CONFIG_NFILE_DESCRIPTORS == 0
net/: Remove all conditional logic based on CONFIG_NFILE_DESCRIPTORS == 0
sched/: Remove all conditional logic based on CONFIG_NFILE_DESCRIPTORS == 0
sched/Kconfig: CONFIG_NFILE_DESCRIPTORS may no longer to set to a value less than 3
configs/: Remove all settings for CONFIG_NFILE_DESCRIPTORS < 3
sched/init/nx_bringup.c: Fix a naming collision.
sched/init: Rename os_start() to nx_start()
sched/init: Rename os_smp* to nx_smp*
sched/init: Rename os_bringup to nx_bringup
sched/init: rename all internal static functions to begin with nx_ vs os_
Provide a user defined callback context for irq's, such that when
registering a callback users can provide a pointer that will get
passed back when the isr is called.
For AVR chips (Atmega2560) Program Counter register larger than 16 bits
EIND represents the most significant byte that is used for EICALL and EIJMP
instructions.
Setting of EIND is normally managed by compiler, but I have seen a situation
when for first 64K flash segment compiler didn't set EINT explicitly. Thus
setting EIND at system startup makes sure we are safe.
Disabling interrupts at the very beginning of system init does not
make sense after reset since interrupts are disabled anyway. But
it is very convenient for debugging purposes, in situations when the
system misbehaves and ocassionally jumps to zero.
This is for forthcoming Atmega2560 support. The Atmega2560 has 24-bit PC
thus, PCH and PCL would become PCH, PCM and PCL (M for Middle). The problem
that in this notation PCM is equivalent to former PCH. This makes compatable
porting kind of difficult, at least for my taste.
Instead PCH becomes PC0 and PCL becomes PC1 (think of the index as order of
bytes pushed to stack when call is performed, PC0 as MSB goes first, PC1
goes to stack second, and for 24-bit PC, PC2 as LDB goes last).
Modify Kconfig to be aware of the new chip.
Add all the interrupt hanler constants and vectors where needed.
Move contsatnts from generic to specific headers when needed.
