Work In Progress

NuttX 9.1 has not been released yet. These Release Notes are a work-in-progress in preparation for the next release of NuttX.

What's New In This Release

Major Changes to Core OS

New Features

Bug Fixes

Major Changes to the Build System

Architectural Support

New Architecture Support

Architectures With Significant Improvements

Driver Support

New Driver Support

Drivers With Significant Improvements

Networking

Applications

Improvements

Bug Fixes

Security Issues Fixed In This Release

Compatibility Concerns

Changes to Build System

If you have are building NuttX for a custom board, you may need to make some of the following changes in build-related files for your board:

Rename EXTRADEFINES to EXTRAFLAGS

In your custom board's scripts/Make.defs file, rename EXTRADEFINES to EXTRAFLAGS.

For example, these lines:

CFLAGS = $(ARCHCFLAGS) $(ARCHWARNINGS) $(ARCHOPTIMIZATION) $(ARCHCPUFLAGS) $(ARCHINCLUDES) $(ARCHDEFINES) $(EXTRADEFINES) -pipe
...
CXXFLAGS = $(ARCHCXXFLAGS) $(ARCHWARNINGSXX) $(ARCHOPTIMIZATION) $(ARCHCPUFLAGS) $(ARCHXXINCLUDES) $(ARCHDEFINES) $(EXTRADEFINES) -pipe
...
CPPFLAGS = $(ARCHINCLUDES) $(ARCHDEFINES) $(EXTRADEFINES)

would change as follows:

CFLAGS = $(ARCHCFLAGS) $(ARCHWARNINGS) $(ARCHOPTIMIZATION) $(ARCHCPUFLAGS) $(ARCHINCLUDES) $(ARCHDEFINES) $(EXTRAFLAGS) -pipe
...
CXXFLAGS = $(ARCHCXXFLAGS) $(ARCHWARNINGSXX) $(ARCHOPTIMIZATION) $(ARCHCPUFLAGS) $(ARCHXXINCLUDES) $(ARCHDEFINES) $(EXTRAFLAGS) -pipe
...
CPPFLAGS = $(ARCHINCLUDES) $(ARCHDEFINES) $(EXTRAFLAGS)

See git commit # 459ad9937377a42785692098ff0d73baaa9551e6 in the main NuttX repository.

If you forget to do this, memory allocations on the heap probably won't work and your user tasks won't start.

To see why, tools/Config.mk assigns a value to KDEFINE such that the preprocessor symbol __KERNEL__ will be defined when certain source files are compiled. KDEFINE is passed to nested invocations of 'make' as EXTRAFLAGS. If your board's scripts/Make.defs still attempts to use EXTRADEFINES, the preprocessor symbol __KERNEL__ will not be defined in some of the places that it should be. Suppose you're building a FLAT build. In this case, include/nuttx/mm/mm.h will not define MM_KERNEL_USRHEAP_INIT like it should, which will cause nx_start.c not to call up_allocate_heap() at startup. Therefore, any attempt to allocate memory on the heap will fail.

Rename src/Makefile to src/Make.defs and Modify

This item pertains only to custom boards that are developed in-tree, meaning under the NuttX boards/ subdirectory. Out-of-tree boards are not affected.

If your custom board directory is in-tree and in a board family that uses a 'boards/ARCH/FAMILY/common' directory (such as boards/arm/stm32/common, boards/arm/cxd56xx/common, etc), then you'll need to make two minor changes to your custom board's src/Makefile:

(1) Rename it from src/Makefile to src/Make.defs, and

(2) Near the end of that file, replace this line, which usually appears at the end:

include $(TOPDIR)/boards/Board.mk

with these three lines:

DEPPATH += --dep-path board
VPATH += :board
CFLAGS += $(shell $(INCDIR) $(INCDIROPT) "$(CC)" $(TOPDIR)$(DELIM)arch$(DELIM)$(CONFIG_ARCH)$(DELIM)src$(DELIM)board$(DELIM)board)

See git commit # 6ca46520df38854bf660f9be54957cceede39ded in the main NuttX repository.

If you forget to do this, 'make' will report an error, "no rule to make libboard.a," and the build will fail.

Rename WINTOOL to CONFIG_CYGWIN_WINTOOL

In your custom board's scripts/Make.defs file, rename any instances of WINTOOL to CONFIG_CYGWIN_WINTOOL.

For example, change this line:

ifeq ($(WINTOOL),y)

to this:

ifeq ($(CONFIG_CYGWIN_WINTOOL),y)

See git commit # bd656888f26c92e8832f0e76b395a5ece7704530 in the main NuttX repository.

Remove INCDIROPT

In your custom board's src/Make.defs file, remove INCDIROPT from CFLAGS.

For example, change this line:

CFLAGS += $(shell $(INCDIR) $(INCDIROPT) "$(CC)" $(TOPDIR)$(DELIM)arch$(DELIM)$(CONFIG_ARCH)$(DELIM)src$(DELIM)board$(DELIM)board)

to this:

CFLAGS += $(shell $(INCDIR) "$(CC)" $(TOPDIR)$(DELIM)arch$(DELIM)$(CONFIG_ARCH)$(DELIM)src$(DELIM)board$(DELIM)board)

This option, which resolves to -w when CONFIG_CYGWIN_WINTOOL is configured, is now appended to INCDIR in tools/Config.mk.

See git commit # 5eae32577e5d5226e5d3027c169eeb369f83f77d in the main NuttX repository.

Remove Unnecessary Variables

In your custom board's scripts/Make.defs file, It is no longer necessary to define the following variables unless your build requires that you assign special values to them:

These variables have been refactored into tools/Config.mk.

See these git commits in the main NuttX repository:

Change ${TOPDIR} to $(TOPDIR)

In your custom board's scripts/Make.defs file, it is recommended to change ${TOPDIR} to $(TOPDIR) for consistency (change curly braces to parenthesis).

See git commit # 7faf3c0254bb63af89f9eb59beefacb4cba26dd9 in the main NuttX repository.

Remove Workaround For Missing $(TOPDIR)/Make.defs

In src/Make.defs or src/Makefile for your custom board or custom apps, the workaround for missing $(TOPDIR)/.config and/or $(TOPDIR)/Make.defs is no longer needed. To remove the workaround, delete the minus sign in front of include .config. This is now handled in the main Makefile and, if those files are missing, will print an error message with hint to run tools/configure.sh <target>.

Change this line, located near the top of the file:

-include $(TOPDIR)/Make.defs

to this:

include $(TOPDIR)/Make.defs

See git commit # 1a95cce1a3c3ed8b04d1d86b7bd744352cca45a2 in the main NuttX repository, and git commit # ead498a7883a654b1d542da94a5fab3ce163361e in the apps repository.

Known Problems In This Release

More Information

How to Download

Release artifacts for all current and past NuttX releases can be downloaded at:

How to Clone the Git Repository

The Apache NuttX project uses Git SCM as its version control system.

There are two primary repositories:

The main "Single Source of Truth" repositories are hosted by the ASF:

These are synchronized with repositories hosted at GitHub:

How to Contact the Community

The main forum for project communication, to ask a question, get involved, or contribute to NuttX, is our mailing list, dev@nuttx.apache.org. The list is publicly archived and searchable at https://lists.apache.org/list.html?dev@nuttx.apache.org. For more information, see NuttX Community.

Enthusiastic Contributors Welcome!

NuttX is a free open-source project. If you'd like to participate, whether it's to enhance documentation (even these release notes) or dive into the nitty gritty of some low-level drivers, please join us! You can join the conversation at our dev mailing list by emailing dev-subscribe@nuttx.apache.org. The mailing list is open to the public and archived. You can browse older messages at https://lists.apache.org/list.html?dev@nuttx.apache.org.