If we are configured to use a kernel stack while in SYSCALL handling, then we need to switch back to the user stack to deliver a signal

Fix a typo in system call when fetching parameter from the stack:  regs[REG_PC]+4 is the address, not regs[REG_PC+4]

execl() is not a system interface.  It belongs in libc and should not have a system call associated with it.

execv() is a basic system interface.  It should not be in libc/ but rather in sched/task.  Its symboltable helper logic also belongs in the kernel but belings in binfmt/ with the other symbol table logic

execv() is a basic system interface.  It should not be in libc/ but rather in sched/task.  Its symboltable helper logic also belongs in the kernel but belings in binfmt/ with the other symbol table logic

execv() is a basic system interface.  It should not be in libc/ but rather in sched/task.  Its symboltable helper logic also belongs in the kernel but belings in binfmt/ with the other symbol table logic

In kernel mode, we have to duplicate the callers argv[] buffer when exec'ing new tasks.  When the argv[] buffer is needed, the caller's address environment will not longer be in place

Add the initial implementation of the process kernel stack logic.  Not yet integrated into the main OS logic nor tested.

Rename everything associated with the dynamic process stack to ustack to make room in the name space for a kstack

Move static helper routines from arm_addrenv.c and may them global so that they can be shared both forthcoming stack address environment logic.

Add the network enabled NSH configuration for the STM32F4Discovery board with the STM32F4DIS-BB base board