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# ====================================================================
#
#      thread.cdl
#
#      configuration data related to the kernel threads
#
# ====================================================================
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# ====================================================================
######DESCRIPTIONBEGIN####
#
# Author(s):      jskov
# Original data:  nickg
# Contributors:
# Date:           1999-07-05
#
#####DESCRIPTIONEND####
#
# ====================================================================

cdl_option CYGFUN_KERNEL_THREADS_TIMER {
    display       "Allow per-thread timers"
    requires      CYGVAR_KERNEL_COUNTERS_CLOCK
    default_value 1
    description   "
        This option controls whether or not the kernel should support
        per-thread clock and alarm related functions. Also some of
        the synchronization primitives such as semaphore and
        condition variable timed wait operations require per-thread
        timer support. If none of these facilities are required then
        the option can be disabled."
}

cdl_option CYGVAR_KERNEL_THREADS_NAME {
    display       "Support optional name for each thread"
    default_value 1
    description   "
        Threads may optionally be supplied with a name string that is
        used to identify them during debugging. This name is only
        present if `this option is defined. Disabling it reduces both
        code and data size."
}

cdl_option CYGVAR_KERNEL_THREADS_LIST {
    display       "Keep track of all threads using a linked list"
    default_value 1
    description   "
        Threads may optionally be placed on a housekeeping list so
        that all threads may be located easily. This is useful mainly
        in conjunction with source-level debugging."
}

cdl_option CYGFUN_KERNEL_THREADS_STACK_LIMIT {
    display       "Keep track of the base of each thread's stack"
    default_value 1
    description   "
        This option makes the kernel keep track of the lower limit on
        each thread's stack. It allows the kernel to adjust the lower
        limit, thus making space for per-thread data. Note that it
        does not imply any form of run-time stack overflow checking."
}

cdl_component CYGFUN_KERNEL_THREADS_STACK_CHECKING {
    display       "Check thread stacks for overflows"
    active_if     CYGPKG_INFRA_DEBUG
    active_if     CYGDBG_USE_ASSERTS
    default_value 1
    description   "
        This option enables a variety of checks for stack overflow
        including signatures at the top and base of thread stacks,
        which are asserted for correctness whenever a thread switches."

    cdl_option CYGFUN_KERNEL_ALL_THREADS_STACK_CHECKING {
        display   "Check all threads whenever possible"
        requires  CYGVAR_KERNEL_THREADS_LIST
        default_value 0
        description "
        This option enables more active checking of all threads for
        wrongdoing.  In theory, checking threads other than the old and new
        executing threads in a thread-switch is pointless, because no other
        thread has run, so no other stack can be exceeded.  But errors such
        as memory scribbling, dangling pointers, overlapping use of store
        or errors accessing objects adjacent to a stack which can be very
        hard to find can be detected this way, saving debug time."
    }

    cdl_option CYGNUM_KERNEL_THREADS_STACK_CHECK_DATA_SIZE {
        display   "Signature size in bytes, at stack top and bottom"
        flavor data
        default_value 32
        legal_values 8 to 512
        description "
        This is the size of the area reserved for a signature at the top
        and bottom of all stacks.  It also provides a buffer zone for
        detecting overflow before external objects are corrupted, hence the
        ability to vary it here.  But if you are short of stack, increasing
        this value will make the overflow more, not less likely, of course."
    }
}

cdl_component CYGFUN_KERNEL_THREADS_STACK_MEASUREMENT {
    display            "Measure stack usage"
    default_value      { 0 != CYGPKG_INFRA_DEBUG }
    description "
        This option allows measurement of each thread's stack by initializing
        it to a predefined value at thread creation time. Later use of the
        cyg_thread_measure_stack_usage() function allows the maximum stack
        usage of the thread so far to be obtained. Note that this is not
        necessarily the true maximum stack usage that the thread will ever
        use since all that has been measured is the stack usage corresponding
        to the code path followed this time, and not the code path that may
        be followed in future."

    cdl_option CYGDBG_KERNEL_THREADS_STACK_MEASUREMENT_VERBOSE_EXIT {
        display        "Output stack usage on thread exit"
        default_value  0
        description    "
            This will output the measured stack usage on the diagnostic
            output when a thread exits."
    }
}

cdl_component CYGVAR_KERNEL_THREADS_DATA {
    display            "Support for per-thread data"
    requires           CYGFUN_KERNEL_THREADS_STACK_LIMIT
    doc                ref/kernel-thread-data.html
    default_value      1
    description "
        It is possible for the kernel to support per-thread data, in
        other words an area of memory specific to each thread which
        can be used to store data for that thread. This per-thread
        data can be used by applications or by other packages such as
        the ISO C library."

    cdl_option CYGNUM_KERNEL_THREADS_DATA_MAX {
        display            "Number of words of per-thread data"
        flavor             data
        legal_values       4 to 32
        default_value      6
        description "
        It is possible for the kernel to support per-thread data, in
        other words an area of memory specific to each thread which
        can be used to store data for that thread. This per-thread
        data can be used by applications or by other packages such as
        the ISO C library. This configuration option controls the
        number of words of per-thread data that the kernel will
        allow. In the current implementation a bitmask is used to identify
        used per-thread data slots and so the maximum legal value must
        remain 32."
    }

    cdl_component CYGNUM_KERNEL_THREADS_DATA_ALL {
        display       "Bitmap of preallocated slots of thread data"
        flavor        data
        calculated    15
        description   "
        Per thread data options. Per thread data support is based loosely
        on that defined by POSIX. Each thread has an array of slots, up to
        CYGNUM_KERNEL_THREADS_DATA_MAX, that may contain data. Some of the
        slots have been preallocated to specific packages. Others may be
        allocated dynamically."

        cdl_option CYGNUM_KERNEL_THREADS_DATA_KERNEL {
            display       "Slot 0 preallocated for the kernel"
            flavor        data
            calculated    0
            description "
                This option defines the index of a per-thread data
                slot which is reserved by
                the eCos kernel
                for private use."
        }
        cdl_option CYGNUM_KERNEL_THREADS_DATA_ITRON {
            display       "Slot 1 preallocated for uITRON"
            flavor        data
            calculated    1
            description "
                This option defines the index of a per-thread data
                slot which is reserved by
                the uITRON compatibility layer
                for private use."
        }
        cdl_option CYGNUM_KERNEL_THREADS_DATA_ERRNO {
            display       "Slot 2 preallocated for errno"
            flavor        data
            calculated    2
            description "
                This option defines the index of a per-thread data
                slot which is reserved for use by an errno variable."
        }
        cdl_option CYGNUM_KERNEL_THREADS_DATA_POSIX {
            display       "Slot 3 preallocated for POSIX"
            flavor        data
            calculated    3
            description "
                This option defines the index of a per-thread data
                slot which is reserved by
                POSIX
                for private use."
        }
    }
}

cdl_component CYGPKG_KERNEL_THREADS_DESTRUCTORS {
    display       "Thread destructors"
    doc           ref/kernel-thread-destructors.html
    default_value 0
    description   "
        This option enables support for registered destructor functions to
        be called on thread exit."
    

    cdl_option CYGNUM_KERNEL_THREADS_DESTRUCTORS {
        display        "Number of possible destructors"
        flavor         data
        legal_values   1 to 65535
        default_value  8
        description    "
                This option gives the number of possible destructors allowed.
                Increasing this will increase the size of every
                thread control structure if per-thread destructors are
                enabled."
    }
    
    cdl_option CYGSEM_KERNEL_THREADS_DESTRUCTORS_PER_THREAD {
        display        "Per-thread destructors"
        default_value  1
        description    "
                Enabling this option makes the thread destructors a per-thread
                property, with each thread having its own list of destructors.
                Disabling this option makes the thread destructor list
                global so all threads have the same destructors."
    }
    
}

cdl_option CYGNUM_KERNEL_THREADS_IDLE_STACK_SIZE {
    display       "Stack size for the idle thread"
    flavor        data
    legal_values  512 to 65536
    default_value 2048
    description   "
        This configuration option specifies the stack size in bytes
        for the idle thread. Unless the HAL is configured to use a
        separate interrupt stack this size must be sufficient to meet
        the requirements of all interrupt handlers - these
        requirements are cumulative if nested interrupted are
        enabled. Depending on the target architecture, the stack size
        typically has to be a multiple of eight or sixteen bytes.
        This will be overridden where it is used if the
        architectural HAL requires a minimum stack size
        to handle interrupts correctly."
}

# ---------------------------------------------------------------------
# Thread-related miscellania.

cdl_option CYGNUM_KERNEL_MAX_SUSPEND_COUNT_ASSERT {
    display       "Maximal suspend count"
    flavor        data
    default_value 500
    description   "
        This option provides for an assertion that the count value for
        counted thread suspends do not exceed set limits.  This is to help
        with debugging, to allow a runaway loop, for example, to be
        detected more easily.
    
        If the option is not defined, no assert is included.  Whether asserts
        are themselves included depends on infrastructure configury in
        infra.h"
}

cdl_option CYGNUM_KERNEL_MAX_COUNTED_WAKE_COUNT_ASSERT {
    display       "Maximal wake count"
    flavor        data
    default_value 500
    description   "
        This option provides for an assertion that the count value for
        counted thread wakeups do not exceed set limits.  This is to
        help with debugging, to allow a runaaway loop, for example, to
        be detected more easily.
    
        If the option is not defined, no assert is included.  Whether asserts
        are themselves included depends on infrastructure configury in
        infra.h"
}     


#if CYGNUM_KERNEL_SCHED_PRIORITIES == 1
#  define CYGIMP_IDLE_THREAD_YIELD
#endif
cdl_option CYGIMP_IDLE_THREAD_YIELD {
    display       "Idle thread must always yield"
    calculated    1
    active_if     (CYGNUM_KERNEL_SCHED_PRIORITIES == 1)
    description   "
        If the scheduler configuration only has a single priority
        level, then the idle thread must yield each time around its loop."
}

# EOF thread.cdl