diff --git a/configs/sabre-6quad/README.txt b/configs/sabre-6quad/README.txt
index beb140cd8b1..e784bae7356 100644
--- a/configs/sabre-6quad/README.txt
+++ b/configs/sabre-6quad/README.txt
@@ -503,10 +503,6 @@ Open Issues:
    handling logic must also take the spinlock.  This will cause the interrupt handlers
    on other CPUs to spin until leave_critical_section() is called.
 
-   NOTE: Currently enter_critical section takes the spinlock before disabling
-   (local) interrupts.  That orderwould have to change or you could potentially get
-   deadlocks if the interrupt handler on the same CPU tries to take the spinlock.
-
 2. Cache Concurency.  This is a complex problem.  There is logic in place now to
    clean CPU0 D-cache before starting a new CPU and for invalidating the D-Cache
    when the new CPU is started.  REVISIT:  Seems that this should not be necessary.
diff --git a/configs/sabre-6quad/nsh/defconfig b/configs/sabre-6quad/nsh/defconfig
index ee0f2839127..dfc9ef8d6f4 100644
--- a/configs/sabre-6quad/nsh/defconfig
+++ b/configs/sabre-6quad/nsh/defconfig
@@ -64,10 +64,13 @@ CONFIG_ARCH_ARM=y
 # CONFIG_ARCH_AVR is not set
 # CONFIG_ARCH_HC is not set
 # CONFIG_ARCH_MIPS is not set
+# CONFIG_ARCH_MISOC is not set
 # CONFIG_ARCH_RGMP is not set
 # CONFIG_ARCH_RENESAS is not set
+# CONFIG_ARCH_RISCV is not set
 # CONFIG_ARCH_SIM is not set
 # CONFIG_ARCH_X86 is not set
+# CONFIG_ARCH_XTENSA is not set
 # CONFIG_ARCH_Z16 is not set
 # CONFIG_ARCH_Z80 is not set
 CONFIG_ARCH="arm"
@@ -260,11 +263,11 @@ CONFIG_ARCH_HAVE_BUTTONS=y
 CONFIG_ARCH_BUTTONS=y
 CONFIG_ARCH_HAVE_IRQBUTTONS=y
 CONFIG_ARCH_IRQBUTTONS=y
-CONFIG_NSH_MMCSDMINOR=0
 
 #
 # Board-Specific Options
 #
+# CONFIG_BOARD_CRASHDUMP is not set
 CONFIG_LIB_BOARDCTL=y
 # CONFIG_BOARDCTL_UNIQUEID is not set
 # CONFIG_BOARDCTL_TSCTEST is not set
@@ -289,6 +292,7 @@ CONFIG_DISABLE_OS_API=y
 CONFIG_USEC_PER_TICK=10000
 # CONFIG_SYSTEM_TIME64 is not set
 # CONFIG_CLOCK_MONOTONIC is not set
+# CONFIG_ARCH_HAVE_TIMEKEEPING is not set
 # CONFIG_JULIAN_TIME is not set
 CONFIG_START_YEAR=2016
 CONFIG_START_MONTH=3
@@ -301,6 +305,7 @@ CONFIG_PREALLOC_TIMERS=4
 #
 # Tasks and Scheduling
 #
+# CONFIG_SMP is not set
 # CONFIG_INIT_NONE is not set
 CONFIG_INIT_ENTRYPOINT=y
 # CONFIG_INIT_FILEPATH is not set
@@ -386,6 +391,7 @@ CONFIG_PTHREAD_STACK_DEFAULT=2048
 # CONFIG_DISABLE_POLL is not set
 CONFIG_DEV_NULL=y
 CONFIG_DEV_ZERO=y
+# CONFIG_DEV_URANDOM is not set
 # CONFIG_DEV_LOOP is not set
 
 #
@@ -401,12 +407,16 @@ CONFIG_DEV_ZERO=y
 # CONFIG_ARCH_HAVE_I2CRESET is not set
 # CONFIG_I2C is not set
 # CONFIG_SPI is not set
+# CONFIG_ARCH_HAVE_SPI_CRCGENERATION is not set
+# CONFIG_ARCH_HAVE_SPI_CS_CONTROL is not set
+# CONFIG_ARCH_HAVE_SPI_BITORDER is not set
 # CONFIG_I2S is not set
 
 #
 # Timer Driver Support
 #
 # CONFIG_TIMER is not set
+# CONFIG_ONESHOT is not set
 # CONFIG_RTC is not set
 # CONFIG_WATCHDOG is not set
 # CONFIG_ANALOG is not set
@@ -414,7 +424,12 @@ CONFIG_DEV_ZERO=y
 # CONFIG_VIDEO_DEVICES is not set
 # CONFIG_BCH is not set
 # CONFIG_INPUT is not set
+
+#
+# IO Expander/GPIO Support
+#
 # CONFIG_IOEXPANDER is not set
+# CONFIG_DEV_GPIO is not set
 
 #
 # LCD Driver Support
@@ -488,9 +503,12 @@ CONFIG_UART1_2STOP=0
 # CONFIG_UART1_IFLOWCONTROL is not set
 # CONFIG_UART1_OFLOWCONTROL is not set
 # CONFIG_UART1_DMA is not set
+# CONFIG_PSEUDOTERM is not set
 # CONFIG_USBDEV is not set
 # CONFIG_USBHOST is not set
+# CONFIG_HAVE_USBTRACE is not set
 # CONFIG_DRIVERS_WIRELESS is not set
+# CONFIG_DRIVERS_CONTACTLESS is not set
 
 #
 # System Logging
@@ -511,6 +529,7 @@ CONFIG_RAMLOG_SYSLOG=y
 # CONFIG_SYSLOG_NONE is not set
 # CONFIG_SYSLOG_FILE is not set
 # CONFIG_CONSOLE_SYSLOG is not set
+# CONFIG_SYSLOG_CHARDEV is not set
 
 #
 # Networking Support
@@ -606,6 +625,8 @@ CONFIG_LIB_HOMEDIR="/"
 # CONFIG_LIBC_FLOATINGPOINT is not set
 CONFIG_LIBC_LONG_LONG=y
 # CONFIG_LIBC_IOCTL_VARIADIC is not set
+# CONFIG_LIBC_WCHAR is not set
+# CONFIG_LIBC_LOCALE is not set
 CONFIG_LIB_RAND_ORDER=1
 # CONFIG_EOL_IS_CR is not set
 # CONFIG_EOL_IS_LF is not set
@@ -633,6 +654,7 @@ CONFIG_ARCH_HAVE_TLS=y
 # CONFIG_LIB_CRC64_FAST is not set
 # CONFIG_LIB_KBDCODEC is not set
 # CONFIG_LIB_SLCDCODEC is not set
+# CONFIG_LIB_HEX2BIN is not set
 
 #
 # Basic CXX Support
@@ -663,10 +685,11 @@ CONFIG_BUILTIN_PROXY_STACKSIZE=1024
 #
 # Examples
 #
+# CONFIG_EXAMPLES_ARCHBUTTONS is not set
 # CONFIG_EXAMPLES_BUTTONS is not set
+# CONFIG_EXAMPLES_CCTYPE is not set
 # CONFIG_EXAMPLES_CHAT is not set
 # CONFIG_EXAMPLES_CONFIGDATA is not set
-# CONFIG_EXAMPLES_CPUHOG is not set
 # CONFIG_EXAMPLES_CXXTEST is not set
 # CONFIG_EXAMPLES_DHCPD is not set
 # CONFIG_EXAMPLES_ELF is not set
@@ -695,9 +718,9 @@ CONFIG_EXAMPLES_NSH_CXXINITIALIZE=y
 # CONFIG_EXAMPLES_NXTEXT is not set
 # CONFIG_EXAMPLES_OSTEST is not set
 # CONFIG_EXAMPLES_PCA9635 is not set
-# CONFIG_EXAMPLES_PIPE is not set
 # CONFIG_EXAMPLES_POSIXSPAWN is not set
 # CONFIG_EXAMPLES_PPPD is not set
+# CONFIG_EXAMPLES_RFID_READUID is not set
 # CONFIG_EXAMPLES_RGBLED is not set
 # CONFIG_EXAMPLES_RGMP is not set
 # CONFIG_EXAMPLES_SENDMAIL is not set
@@ -740,6 +763,7 @@ CONFIG_EXAMPLES_NSH_CXXINITIALIZE=y
 # CONFIG_INTERPRETERS_BAS is not set
 # CONFIG_INTERPRETERS_FICL is not set
 # CONFIG_INTERPRETERS_MICROPYTHON is not set
+# CONFIG_INTERPRETERS_MINIBASIC is not set
 # CONFIG_INTERPRETERS_PCODE is not set
 
 #
@@ -806,12 +830,12 @@ CONFIG_NSH_DISABLE_LOSMART=y
 # CONFIG_NSH_DISABLE_LS is not set
 # CONFIG_NSH_DISABLE_MB is not set
 # CONFIG_NSH_DISABLE_MKDIR is not set
-# CONFIG_NSH_DISABLE_MKFIFO is not set
 # CONFIG_NSH_DISABLE_MKRD is not set
 # CONFIG_NSH_DISABLE_MH is not set
 # CONFIG_NSH_DISABLE_MOUNT is not set
 # CONFIG_NSH_DISABLE_MV is not set
 # CONFIG_NSH_DISABLE_MW is not set
+CONFIG_NSH_DISABLE_PRINTF=y
 # CONFIG_NSH_DISABLE_PS is not set
 # CONFIG_NSH_DISABLE_PUT is not set
 # CONFIG_NSH_DISABLE_PWD is not set
@@ -828,6 +852,7 @@ CONFIG_NSH_DISABLE_LOSMART=y
 # CONFIG_NSH_DISABLE_USLEEP is not set
 # CONFIG_NSH_DISABLE_WGET is not set
 # CONFIG_NSH_DISABLE_XD is not set
+CONFIG_NSH_MMCSDMINOR=0
 
 #
 # Configure Command Options
@@ -869,7 +894,7 @@ CONFIG_NSH_ARCHINIT=y
 # CONFIG_SYSTEM_CLE is not set
 # CONFIG_SYSTEM_CUTERM is not set
 # CONFIG_SYSTEM_FREE is not set
-# CONFIG_LIB_HEX2BIN is not set
+# CONFIG_SYSTEM_HEX2BIN is not set
 # CONFIG_SYSTEM_HEXED is not set
 # CONFIG_SYSTEM_INSTALL is not set
 # CONFIG_SYSTEM_RAMTEST is not set
@@ -879,6 +904,8 @@ CONFIG_READLINE_ECHO=y
 # CONFIG_READLINE_TABCOMPLETION is not set
 # CONFIG_READLINE_CMD_HISTORY is not set
 # CONFIG_SYSTEM_SUDOKU is not set
+# CONFIG_SYSTEM_SYSTEM is not set
+# CONFIG_SYSTEM_TEE is not set
 # CONFIG_SYSTEM_UBLOXMODEM is not set
 # CONFIG_SYSTEM_VI is not set
 # CONFIG_SYSTEM_ZMODEM is not set
diff --git a/configs/sabre-6quad/smp/defconfig b/configs/sabre-6quad/smp/defconfig
index 4205d007810..23afd07fe96 100644
--- a/configs/sabre-6quad/smp/defconfig
+++ b/configs/sabre-6quad/smp/defconfig
@@ -64,10 +64,13 @@ CONFIG_ARCH_ARM=y
 # CONFIG_ARCH_AVR is not set
 # CONFIG_ARCH_HC is not set
 # CONFIG_ARCH_MIPS is not set
+# CONFIG_ARCH_MISOC is not set
 # CONFIG_ARCH_RGMP is not set
 # CONFIG_ARCH_RENESAS is not set
+# CONFIG_ARCH_RISCV is not set
 # CONFIG_ARCH_SIM is not set
 # CONFIG_ARCH_X86 is not set
+# CONFIG_ARCH_XTENSA is not set
 # CONFIG_ARCH_Z16 is not set
 # CONFIG_ARCH_Z80 is not set
 CONFIG_ARCH="arm"
@@ -263,11 +266,11 @@ CONFIG_ARCH_HAVE_BUTTONS=y
 CONFIG_ARCH_BUTTONS=y
 CONFIG_ARCH_HAVE_IRQBUTTONS=y
 CONFIG_ARCH_IRQBUTTONS=y
-CONFIG_NSH_MMCSDMINOR=0
 
 #
 # Board-Specific Options
 #
+# CONFIG_BOARD_CRASHDUMP is not set
 CONFIG_LIB_BOARDCTL=y
 # CONFIG_BOARDCTL_UNIQUEID is not set
 # CONFIG_BOARDCTL_TSCTEST is not set
@@ -292,6 +295,7 @@ CONFIG_DISABLE_OS_API=y
 CONFIG_USEC_PER_TICK=10000
 # CONFIG_SYSTEM_TIME64 is not set
 # CONFIG_CLOCK_MONOTONIC is not set
+# CONFIG_ARCH_HAVE_TIMEKEEPING is not set
 # CONFIG_JULIAN_TIME is not set
 CONFIG_START_YEAR=2016
 CONFIG_START_MONTH=3
@@ -393,6 +397,7 @@ CONFIG_PTHREAD_STACK_DEFAULT=2048
 # CONFIG_DISABLE_POLL is not set
 CONFIG_DEV_NULL=y
 CONFIG_DEV_ZERO=y
+# CONFIG_DEV_URANDOM is not set
 # CONFIG_DEV_LOOP is not set
 
 #
@@ -408,12 +413,16 @@ CONFIG_DEV_ZERO=y
 # CONFIG_ARCH_HAVE_I2CRESET is not set
 # CONFIG_I2C is not set
 # CONFIG_SPI is not set
+# CONFIG_ARCH_HAVE_SPI_CRCGENERATION is not set
+# CONFIG_ARCH_HAVE_SPI_CS_CONTROL is not set
+# CONFIG_ARCH_HAVE_SPI_BITORDER is not set
 # CONFIG_I2S is not set
 
 #
 # Timer Driver Support
 #
 # CONFIG_TIMER is not set
+# CONFIG_ONESHOT is not set
 # CONFIG_RTC is not set
 # CONFIG_WATCHDOG is not set
 # CONFIG_ANALOG is not set
@@ -421,7 +430,12 @@ CONFIG_DEV_ZERO=y
 # CONFIG_VIDEO_DEVICES is not set
 # CONFIG_BCH is not set
 # CONFIG_INPUT is not set
+
+#
+# IO Expander/GPIO Support
+#
 # CONFIG_IOEXPANDER is not set
+# CONFIG_DEV_GPIO is not set
 
 #
 # LCD Driver Support
@@ -495,9 +509,12 @@ CONFIG_UART1_2STOP=0
 # CONFIG_UART1_IFLOWCONTROL is not set
 # CONFIG_UART1_OFLOWCONTROL is not set
 # CONFIG_UART1_DMA is not set
+# CONFIG_PSEUDOTERM is not set
 # CONFIG_USBDEV is not set
 # CONFIG_USBHOST is not set
+# CONFIG_HAVE_USBTRACE is not set
 # CONFIG_DRIVERS_WIRELESS is not set
+# CONFIG_DRIVERS_CONTACTLESS is not set
 
 #
 # System Logging
@@ -518,6 +535,7 @@ CONFIG_RAMLOG_SYSLOG=y
 # CONFIG_SYSLOG_NONE is not set
 # CONFIG_SYSLOG_FILE is not set
 # CONFIG_CONSOLE_SYSLOG is not set
+# CONFIG_SYSLOG_CHARDEV is not set
 
 #
 # Networking Support
@@ -614,6 +632,8 @@ CONFIG_LIB_HOMEDIR="/"
 # CONFIG_LIBC_FLOATINGPOINT is not set
 CONFIG_LIBC_LONG_LONG=y
 # CONFIG_LIBC_IOCTL_VARIADIC is not set
+# CONFIG_LIBC_WCHAR is not set
+# CONFIG_LIBC_LOCALE is not set
 CONFIG_LIB_RAND_ORDER=1
 # CONFIG_EOL_IS_CR is not set
 # CONFIG_EOL_IS_LF is not set
@@ -641,6 +661,7 @@ CONFIG_ARCH_HAVE_TLS=y
 # CONFIG_LIB_CRC64_FAST is not set
 # CONFIG_LIB_KBDCODEC is not set
 # CONFIG_LIB_SLCDCODEC is not set
+# CONFIG_LIB_HEX2BIN is not set
 
 #
 # Basic CXX Support
@@ -671,10 +692,11 @@ CONFIG_BUILTIN_PROXY_STACKSIZE=1024
 #
 # Examples
 #
+# CONFIG_EXAMPLES_ARCHBUTTONS is not set
 # CONFIG_EXAMPLES_BUTTONS is not set
+# CONFIG_EXAMPLES_CCTYPE is not set
 # CONFIG_EXAMPLES_CHAT is not set
 # CONFIG_EXAMPLES_CONFIGDATA is not set
-# CONFIG_EXAMPLES_CPUHOG is not set
 # CONFIG_EXAMPLES_CXXTEST is not set
 # CONFIG_EXAMPLES_DHCPD is not set
 # CONFIG_EXAMPLES_ELF is not set
@@ -703,9 +725,9 @@ CONFIG_EXAMPLES_NSH_CXXINITIALIZE=y
 # CONFIG_EXAMPLES_NXTEXT is not set
 # CONFIG_EXAMPLES_OSTEST is not set
 # CONFIG_EXAMPLES_PCA9635 is not set
-# CONFIG_EXAMPLES_PIPE is not set
 # CONFIG_EXAMPLES_POSIXSPAWN is not set
 # CONFIG_EXAMPLES_PPPD is not set
+# CONFIG_EXAMPLES_RFID_READUID is not set
 # CONFIG_EXAMPLES_RGBLED is not set
 # CONFIG_EXAMPLES_RGMP is not set
 # CONFIG_EXAMPLES_SENDMAIL is not set
@@ -748,6 +770,7 @@ CONFIG_EXAMPLES_NSH_CXXINITIALIZE=y
 # CONFIG_INTERPRETERS_BAS is not set
 # CONFIG_INTERPRETERS_FICL is not set
 # CONFIG_INTERPRETERS_MICROPYTHON is not set
+# CONFIG_INTERPRETERS_MINIBASIC is not set
 # CONFIG_INTERPRETERS_PCODE is not set
 
 #
@@ -814,12 +837,12 @@ CONFIG_NSH_DISABLE_LOSMART=y
 # CONFIG_NSH_DISABLE_LS is not set
 # CONFIG_NSH_DISABLE_MB is not set
 # CONFIG_NSH_DISABLE_MKDIR is not set
-# CONFIG_NSH_DISABLE_MKFIFO is not set
 # CONFIG_NSH_DISABLE_MKRD is not set
 # CONFIG_NSH_DISABLE_MH is not set
 # CONFIG_NSH_DISABLE_MOUNT is not set
 # CONFIG_NSH_DISABLE_MV is not set
 # CONFIG_NSH_DISABLE_MW is not set
+CONFIG_NSH_DISABLE_PRINTF=y
 # CONFIG_NSH_DISABLE_PS is not set
 # CONFIG_NSH_DISABLE_PUT is not set
 # CONFIG_NSH_DISABLE_PWD is not set
@@ -836,6 +859,7 @@ CONFIG_NSH_DISABLE_LOSMART=y
 # CONFIG_NSH_DISABLE_USLEEP is not set
 # CONFIG_NSH_DISABLE_WGET is not set
 # CONFIG_NSH_DISABLE_XD is not set
+CONFIG_NSH_MMCSDMINOR=0
 
 #
 # Configure Command Options
@@ -877,7 +901,7 @@ CONFIG_NSH_ARCHINIT=y
 # CONFIG_SYSTEM_CLE is not set
 # CONFIG_SYSTEM_CUTERM is not set
 # CONFIG_SYSTEM_FREE is not set
-# CONFIG_LIB_HEX2BIN is not set
+# CONFIG_SYSTEM_HEX2BIN is not set
 # CONFIG_SYSTEM_HEXED is not set
 # CONFIG_SYSTEM_INSTALL is not set
 # CONFIG_SYSTEM_RAMTEST is not set
@@ -887,6 +911,8 @@ CONFIG_READLINE_ECHO=y
 # CONFIG_READLINE_TABCOMPLETION is not set
 # CONFIG_READLINE_CMD_HISTORY is not set
 # CONFIG_SYSTEM_SUDOKU is not set
+# CONFIG_SYSTEM_SYSTEM is not set
+# CONFIG_SYSTEM_TEE is not set
 # CONFIG_SYSTEM_UBLOXMODEM is not set
 # CONFIG_SYSTEM_VI is not set
 # CONFIG_SYSTEM_ZMODEM is not set
diff --git a/sched/irq/irq_csection.c b/sched/irq/irq_csection.c
index 4cc2412ae74..115b717a187 100644
--- a/sched/irq/irq_csection.c
+++ b/sched/irq/irq_csection.c
@@ -86,6 +86,21 @@ volatile cpu_set_t g_cpu_irqset;
 irqstate_t enter_critical_section(void)
 {
   FAR struct tcb_s *rtcb;
+  irqstate_t ret;
+
+  /* Disable interrupts.
+   *
+   * NOTE 1: Ideally this should disable interrupts on all CPUs, but most
+   * architectures only support disabling interrupts on the local CPU.
+   * NOTE 2: Interrupts may already be disabled, but we call up_irq_save()
+   * unconditionally because we need to return valid interrupt status in any
+   * event.
+   * NOTE 3: We disable local interrupts BEFORE taking the spinlock in order
+   * to prevent possible waits on the spinlock from interrupt handling on
+   * the local CPU.
+   */
+
+  ret = up_irq_save();
 
   /* Check if we were called from an interrupt handler and that the tasks
    * lists have been initialized.
@@ -133,11 +148,9 @@ irqstate_t enter_critical_section(void)
         }
     }
 
-  /* Then disable interrupts (they may already be disabled, be we need to
-   * return valid interrupt status in any event).
-   */
+  /* Return interrupt status */
 
-  return up_irq_save();
+  return ret;
 }
 #else /* defined(CONFIG_SCHED_INSTRUMENTATION_CSECTION) */
 irqstate_t enter_critical_section(void)