Globally configurable stack checks, R10 is always fixed

makefiles/toolchain_gnu-arm-eabi.mk

@@ -80,20 +80,18 @@ ARCHCPUFLAGS_CORTEXM3	 = -mcpu=cortex-m3 \
 			   -march=armv7-m \
 			   -mfloat-abi=soft
 
-ARCHINSTRUMENTATIONDEFINES_CORTEXM4F = -ffixed-r10
-
-ARCHINSTRUMENTATIONDEFINES_CORTEXM4 = -ffixed-r10
-
-ARCHINSTRUMENTATIONDEFINES_CORTEXM3 =
-
 # Enabling stack checks if requested
 #
 ENABLE_STACK_CHECKS ?= 0
 ifneq ($(ENABLE_STACK_CHECKS),0)
 $(info Stack checks enabled)
-ARCHINSTRUMENTATIONDEFINES_CORTEXM4F += -finstrument-functions
-ARCHINSTRUMENTATIONDEFINES_CORTEXM4  += -finstrument-functions
-ARCHINSTRUMENTATIONDEFINES_CORTEXM3  +=
+ARCHINSTRUMENTATIONDEFINES_CORTEXM4F = -finstrument-functions -ffixed-r10
+ARCHINSTRUMENTATIONDEFINES_CORTEXM4  = -finstrument-functions -ffixed-r10
+ARCHINSTRUMENTATIONDEFINES_CORTEXM3  =
+else
+ARCHINSTRUMENTATIONDEFINES_CORTEXM4F = -ffixed-r10
+ARCHINSTRUMENTATIONDEFINES_CORTEXM4  = -ffixed-r10
+ARCHINSTRUMENTATIONDEFINES_CORTEXM3  =
 endif
 
 # Pick the right set of flags for the architecture.

nuttx-configs/px4fmu-v2/nsh/Make.defs

@@ -62,8 +62,14 @@ ARCHCPUFLAGS		 = -mcpu=cortex-m4 \
 
 
 # enable precise stack overflow tracking
+ENABLE_STACK_CHECKS ?= 0
+ifneq ($(ENABLE_STACK_CHECKS),0)
+$(info Stack checks enabled)
 INSTRUMENTATIONDEFINES	 = -finstrument-functions \
 			   -ffixed-r10
+else
+INSTRUMENTATIONDEFINES	 = -ffixed-r10
+endif
 
 # pull in *just* libm from the toolchain ... this is grody
 LIBM			 = "${shell $(CC) $(ARCHCPUFLAGS) -print-file-name=libm.a}"

src/modules/uavcan/module.mk

@@ -40,9 +40,6 @@ MODULE_COMMAND = uavcan
 
 MAXOPTIMIZATION = -O3
 
-# Instrumentation makes the CPU load about 3 times higher, see https://github.com/PX4/Firmware/issues/1417
-INSTRUMENTATIONDEFINES += -fno-instrument-functions
-
 # Main
 SRCS += uavcan_main.cpp              \
         uavcan_clock.cpp             \