Commit graph

454 commits

Author SHA1 Message Date
Keith Packard
2200861b96 lib/libc/picolibc: Use SDK picolibc by default
When using the Zephyr SDK toolchain, prefer the pre-built version of
picolibc over using the picolibc module. This will reduce the time it takes
to build applications.

Signed-off-by: Keith Packard <keithp@keithp.com>
2023-05-25 13:33:04 +00:00
Lucian Zala
2fae5e86b8 libc: minimal: strtoll: Remove typo in SPDX-License-Identifier
BSD-3-Clause-UC is not a valid license name and spdx validator
generates a Warning! when detected. Most probably a typo from
old version of strtoll.c licenced as BSD-4-Clause-UC.

see commit: 570ed08

Signed-off-by: Lucian Zala <zala.lucian@gmail.com>
2023-05-11 06:04:30 -04:00
Keith Packard
5279acba9d libc/common: Make sure malloc arena is PoT aligned on Risc-V
The malloc arena needs to be aligned to a suitable size on Risc-V, and the
Z_RISCV_STACK_GUARD_SIZE variable is a helpful proxy for what size that
is. However, that is not always a power of two, so round it up to make the
linker capable of performing the necessary allocation.

Signed-off-by: Keith Packard <keithp@keithp.com>
2023-05-11 01:25:01 +09:00
Keith Packard
69f4f39aef libc/common: Always build aligned_alloc
This function may be used by system libraries (like libstdc++), so instead
of gating compile on target language, always build this function and gate
API visibility in header files instead.

Signed-off-by: Keith Packard <keithp@keithp.com>
2023-05-11 01:25:01 +09:00
Keith Packard
f74455127d libc/common: Refine check for xtensa _heap_sentry
Not all xtensa targets define the top of usable RAM via the _heap_sentry
address; it looks like the list is limited to esp32, esp32s2, esp32s3 and
intel parts. The first three all define HAS_ESPRESSIF_HAL, so key the test
using that or SOC_FAMILY_INTEL_ADSP.

Signed-off-by: Keith Packard <keithp@keithp.com>
2023-05-11 01:25:01 +09:00
Keith Packard
706d9f6db2 libc/common: Use static initializer for z_malloc_heap_mutex
Instead of explicitly initializing the mutex at runtime, use
SYS_MUTEX_DEFINE to initialize it at build time instead.

Signed-off-by: Keith Packard <keithp@keithp.com>
2023-05-11 01:25:01 +09:00
Keith Packard
9b90f2a351 libc/picolibc: Switch to common malloc implementation
Enable the common malloc implementation when using picolibc. Support
existing Picolibc configurations by respecting existing PICOLIBC_HEAP_SIZE
settings.

When PICOLIBC_HEAP_SIZE is set to a value other than -2, then
*always* set COMMON_LIBC_MALLOC_ARENA_SIZE to that value.

Signed-off-by: Keith Packard <keithp@keithp.com>
2023-05-09 01:29:16 +09:00
Keith Packard
0a44b419ab libc/common: Allocate default malloc arena for non-minimal-libc uses
When using the common malloc implementation on systems not using the
minimal C library, allocate a reasonable default malloc heap according to
the following rules (adopted from the Picolibc heap size defaults):

* When an MMU is available, allocate 16kB.
* When USERSPACE is enabled for a device with an MPU require PoT alignment,
  allocate 1024 bytes
* Otherwise, use all available memory.

Signed-off-by: Keith Packard <keithp@keithp.com>
2023-05-09 01:29:16 +09:00
Keith Packard
420bf1e444 libc/common: Change how legacy malloc setting works
Change the default value of MINIMAL_LIBC_MALLOC_ARENA_SIZE from 0 to an
otherwise invalid value of -2. This allows the common malloc code to
distinguish between an application which explicitly sets the malloc arena
to zero bytes from an application which does not set the variable at all.

When MINIMAL_LIBC_MALLOC_ARENA_SIZE is set to a value other than -2, then
*always* set COMMON_LIBC_MALLOC_ARENA_SIZE to that value. Emit a compile
warning to let the developer know that their application is using a
deprecated Kconfig variable.

This means that MINIMAL_LIBC_MALLOC_ARENA_SIZE now always overrides
COMMON_LIBC_MALLOC_ARENA_SIZE, but an application setting both will already
be getting a configuration warning for setting the DEPRECATED value
anyways, which should serve as an adequate indication to the user.

Signed-off-by: Keith Packard <keithp@keithp.com>
2023-05-09 01:29:16 +09:00
Keith Packard
32a437cbc8 libc/common: Handle MMU/MPU/USERSPACE and alignment requirements in malloc
When CONFIG_COMMON_LIBC_MALLOC_ARENA_SIZE is set to -1, make the malloc
arena use all remaining RAM. When an MMU exists, allocate the arena at
startup using k_mem_map. Otherwise, compute the available memory
automatically and use that.

When an MPU is being used to manage the malloc arena, make sure the heap
respects any MPU alignment requirements. Otherwise, align the heap to
sizeof(double).

Signed-off-by: Keith Packard <keithp@keithp.com>
2023-05-09 01:29:16 +09:00
Kumar Gala
161e4a05a2 libc: Move abort into common
Move the abort implementation into common so its shared among the
libc.  As part of this start using the common abort on newlib.

Signed-off-by: Kumar Gala <kumar.gala@intel.com>
2023-05-08 09:59:27 +02:00
Kumar Gala
ca4dc50ec1 libc: Move strnlen into common
Move the strnlen implementation into common so its available to any
libc that may not implement strnlen.

Signed-off-by: Kumar Gala <kumar.gala@intel.com>
2023-05-08 09:59:27 +02:00
Keith Packard
e0b540d432 lib/libc: Mark picolibc as providing full C library support
Select FULL_LIBC_SUPPORTED when picolibc is available.

Add picolibc as a secondary default C library when REQUIRES_FULL_LIBC is
selected. This is necessary as tests gated on FULL_LIBC_SUPPORTED need to
be sure that a full C library will be selected -- if only picolibc is
available, those tests will need to select that.

This should permit use of a picolibc-only crosstool-ng toolchain in
testing.

Signed-off-by: Keith Packard <keithp@keithp.com>
2023-04-27 20:18:11 +09:00
Keith Packard
214a3c5fa8 lib/libc: Add FULL_LIBC_SUPPORTED helper Kconfig symbol
This symbol is selected when the target has any full libc available. This
allows tests to filter on this condition. It doesn't depend on whether the
application actually selects that library, only whether requesting a full C
library would work.

Signed-off-by: Keith Packard <keithp@keithp.com>
2023-04-27 20:18:11 +09:00
Keith Packard
3ffde85895 lib/libc: newlib use depends upon newlib being supported
Before allowing newlib to be selected as the C library, ensure that it is
available for the target.

Signed-off-by: Keith Packard <keithp@keithp.com>
2023-04-27 20:18:11 +09:00
Keith Packard
45733aa925 lib/libc: Add NEWLIB_LIBC_SUPPORTED
This reflects whether newlib is available in the environment. This
symbol should be used in place of TOOLCHAIN_HAS_NEWLIB.

Signed-off-by: Keith Packard <keithp@keithp.com>
2023-04-27 20:18:11 +09:00
Keith Packard
02262d7367 lib/libc: Replace SUPPORT_MINIMAL_LIBC with MINIMAL_LIBC_SUPPORTED
Clean up libc-related symbols to use a common pattern.

Signed-off-by: Keith Packard <keithp@keithp.com>
2023-04-27 20:18:11 +09:00
Keith Packard
2d1efd5b41 lib/libc: Allow REQUIRES_FULL_LIBC to be selected by applications
Add a prompt to the Kconfig symbol so that applications can select this in
their configuration to guide C library selection away from the minimal C
library.

Signed-off-by: Keith Packard <keithp@keithp.com>
2023-04-27 20:18:11 +09:00
Keith Packard
6a698f482a lib/libc: Move helper symbols above C library menu
Restructure the file so that the only elements within 'menu "C Library"'
are the library choices.

Signed-off-by: Keith Packard <keithp@keithp.com>
2023-04-27 20:18:11 +09:00
Keith Packard
a9c62caab7 lib/libc: Move malloc from minimal to common library
This will (eventually) permit use of a common malloc implementation with
other C libraries, reducing the amount of Zephyr-specific code required
to support each C library.

Signed-off-by: Keith Packard <keithp@keithp.com>
2023-04-27 20:17:24 +09:00
Keith Packard
52e57ef17f lib/libc: Allow common library to be empty
This allows the C library common library to be empty if no pieces are
needed, eliminating cmake warnings.

Signed-off-by: Keith Packard <keithp@keithp.com>
2023-04-27 20:17:24 +09:00
Kumar Gala
48cd295a7f armstdc: add limits.h header
Add limits.h header that defines PATH_MAX as this is not defined
by the toolchain headers.

The value of 256 for PATH_MAX is based on how it is set in
lib/libc/minimal/include/limits.h.

Signed-off-by: Kumar Gala <kumar.gala@intel.com>
2023-04-25 12:18:55 +02:00
Keith Packard
25b2db74e0 libc/minimal: Add -fno-builtin option
This ensures that the compiler won't end up recognizing patterns in code
that map to known built-in functions, like noticing that the memcpy
implementation looks a lot like a memory copy operation that could be
replaced by a call to ... memcpy.

When built with -ffreestanding, this has no effect as that option always
enables -fno-builtin.

Signed-off-by: Keith Packard <keithp@keithp.com>
2023-04-25 06:18:26 -04:00
Keith Packard
bc2075e31b libc/minimal: Use CODE_UNREACHABLE in abort()
This allows this function to build without -ffreestanding for testing.

Signed-off-by: Keith Packard <keithp@keithp.com>

fixup
2023-04-25 06:18:26 -04:00
Keith Packard
27b7ace9fd libc/minimal: Create "real" functions for putc and putchar
When gcc is building without -fno-builtin, it will optimize calls like
printf("\n") into a call to putchar('\n'), but it won't use a static inline
in that case, instead insisting on a real function.

To make this a bit easier, adopt the usual C library practice of making
putc and putchar macros instead of static inline functions. There's no loss
of typechecking as the parameters are directly passed to underlying
functions with the same parameter types.

Signed-off-by: Keith Packard <keithp@keithp.com>
2023-04-25 06:18:26 -04:00
Keith Packard
b5caccb2ba lib/picolibc: Use zephyr_libc_link_libraries to find toolchain lib
When using the toolchain C library, that must be added to the link command
after all other libraries and modules in the system to resolve undefined
symbols.

Signed-off-by: Keith Packard <keithp@keithp.com>
2023-04-17 11:13:17 +02:00
Keith Packard
6c5d806bcb toolchain: Add COMPILER_FREESTANDING to control use of -ffreestanding
Add an explicit compiler configuration, COMPILER_FREESTANDING, which
controls whether the compiler should operate in freestanding or hosted mode
(according to the C and C++ language specifications.

This depends on having a C library which conforms with the language
specification, and the minimal C library does not. Have the minimal C
library select COMPILER_FREESTANDING to continue using freestanding mode
with that library.

For other C libraries, leave this disabled by default while allowing users
to enable it if they want to go back to the previous configuration.

Signed-off-by: Keith Packard <keithp@keithp.com>
2023-04-14 21:36:31 +09:00
Gerard Marull-Paretas
a5fd0d184a init: remove the need for a dummy device pointer in SYS_INIT functions
The init infrastructure, found in `init.h`, is currently used by:

- `SYS_INIT`: to call functions before `main`
- `DEVICE_*`: to initialize devices

They are all sorted according to an initialization level + a priority.
`SYS_INIT` calls are really orthogonal to devices, however, the required
function signature requires a `const struct device *dev` as a first
argument. The only reason for that is because the same init machinery is
used by devices, so we have something like:

```c
struct init_entry {
	int (*init)(const struct device *dev);
	/* only set by DEVICE_*, otherwise NULL */
	const struct device *dev;
}
```

As a result, we end up with such weird/ugly pattern:

```c
static int my_init(const struct device *dev)
{
	/* always NULL! add ARG_UNUSED to avoid compiler warning */
	ARG_UNUSED(dev);
	...
}
```

This is really a result of poor internals isolation. This patch proposes
a to make init entries more flexible so that they can accept sytem
initialization calls like this:

```c
static int my_init(void)
{
	...
}
```

This is achieved using a union:

```c
union init_function {
	/* for SYS_INIT, used when init_entry.dev == NULL */
	int (*sys)(void);
	/* for DEVICE*, used when init_entry.dev != NULL */
	int (*dev)(const struct device *dev);
};

struct init_entry {
	/* stores init function (either for SYS_INIT or DEVICE*)
	union init_function init_fn;
	/* stores device pointer for DEVICE*, NULL for SYS_INIT. Allows
	 * to know which union entry to call.
	 */
	const struct device *dev;
}
```

This solution **does not increase ROM usage**, and allows to offer clean
public APIs for both SYS_INIT and DEVICE*. Note that however, init
machinery keeps a coupling with devices.

**NOTE**: This is a breaking change! All `SYS_INIT` functions will need
to be converted to the new signature. See the script offered in the
following commit.

Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>

init: convert SYS_INIT functions to the new signature

Conversion scripted using scripts/utils/migrate_sys_init.py.

Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>

manifest: update projects for SYS_INIT changes

Update modules with updated SYS_INIT calls:

- hal_ti
- lvgl
- sof
- TraceRecorderSource

Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>

tests: devicetree: devices: adjust test

Adjust test according to the recently introduced SYS_INIT
infrastructure.

Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>

tests: kernel: threads: adjust SYS_INIT call

Adjust to the new signature: int (*init_fn)(void);

Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
2023-04-12 14:28:07 +00:00
Kumar Gala
af79019146 armstdc: add string.h & strings.h header
Add string.h header that declerates prototype for strnlen()
as this is not provided by the toolchain headers.

Add strings.h to allow anything that expects strncasecmp() to
be defined there to build correctly.  The arm toolchain actually
defines strncasecmp() in <string.h> so we just have <strings.h>
include <string.h>.

Signed-off-by: Kumar Gala <kumar.gala@intel.com>
2023-04-10 16:32:10 -05:00
Kumar Gala
20b21091cc armstdc: Fixup headers as needed by posix
* Move 'struct _timespec' into sys/_timespec.h as expected by
  <posix/time.h>.

* Introduce 'struct timeval' in sys/_timeval.h as expected by
  <posix/time.h>.

* Add mode_t to <sys/types.h> as expected by <posix/stat.h>

Signed-off-by: Kumar Gala <kumar.gala@intel.com>
2023-04-10 16:32:10 -05:00
Kumar Gala
82538a2d28 armclang: add empty sys/cdefs.h
Various headers include <sys/cdefs.h> like zephyr/posix/sys/stat.h.
When building with the arm-clang toolchain we utilize armstdc
so we need an empty cdefs.h similar to what minimal libc has so
things will build.

Signed-off-by: Kumar Gala <kumar.gala@intel.com>
2023-04-10 16:32:10 -05:00
Kumar Gala
0e43b8861b libc: fix armclang compiler warnings with is*() functions
We get compile warnings of the form:

error: converting the result of
'<<' to a boolean; did you mean
'((__aeabi_ctype_table_ + 1)[(byte)] << 28) != 0'?
 [-Werror,-Wint-in-bool-context]
                if (!isprint(byte)) {
                     ^

Since isprint (and the other is* functions) return an int, change check
to an explicit test against the return value.

Signed-off-by: Kumar Gala <kumar.gala@intel.com>
2023-04-04 13:47:34 +02:00
Kumar Gala
672aeace88 libc: share time() between minimal libc and armclang libc
Introduce a place to share implementations of libc functions that
are needed by different libc versions.  Place time() in this common
location so it can be shared when building for either minimal libc or
armclang libc.

Signed-off-by: Kumar Gala <kumar.gala@intel.com>
2023-03-27 09:49:40 +02:00
Anas Nashif
0e0f878ddc picolibc: picolibc support still not complete with many toolchains
Clang support still work in progress in zephyr. So for now enable only
on gcc based toolchains.

We should enable this back for more toolchains once we have full clang
support and are able to verify.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
2023-02-07 18:16:10 +01:00
Keith Packard
9a0aebc5fd lib/libc: Enable picolibc on qemu_x86_tiny
With all of the test suite issues on this board fixed, qemu_x86_tiny should
now be usable with picolibc.

Signed-off-by: Keith Packard <keithp@keithp.com>
2023-01-30 23:46:55 +00:00
Keith Packard
67ca25467b libc: Add remaining picolibc-supported targets
Picolibc now supports all of the Zephyr SDK target architectures for C.

qemu_x86_tiny needs fixes to get the libc partition linked
into the right spot. See issue #54148

Signed-off-by: Keith Packard <keithp@keithp.com>
2023-01-27 06:27:43 -05:00
Keith Packard
13dfbaebd1 libc/picolibc: Clean up Picolibc Kconfig for C++
libstdc++ is supported with Picolibc only when the toolchain version of
Picolibc is use -- libstdc++ must be built using a specific Picolibc build
and libstdc++ is included with the toolchain.

Ideally, we'd allow the use of the Picolibc module whenever we weren't
using the GNU libstdc++, including when using the minimal libc++. However,
the obvious dependency settings create a loop:

config PICOLIBC
    depends on PICOLIBC_SUPPORTED

config PICOLIBC_SUPPORTED
    depends on !(GLIBCXX_LIBCPP && "$(ZEPHYR_TOOCHAIN_VARIANT" = "zephyr")

config GLIBCXX_LIBCPP
    depends on NEWLIB_LIBC || PICOLIBC

To break this loop, we replace GLIBCXX_LIBCPP in the second block with
CPP:

config PICOLIBC_SUPPORTED
    depends on !(CPP && "$(ZEPHYR_TOOCHAIN_VARIANT" = "zephyr")

This means that picolibc cannot be used with any C++ apps when using the
Zephyr SDK, even when not using the GNU libstdc++. However, Zephyr SDK 0.16
will come with an additional Kconfig file that includes:

config PICOLIBC_SUPPORTED
    def_bool y
    depends on "$(ZEPHYR_TOOLCHAIN_VARIANT)" = "zephyr"

This will override the Kconfig bits included in Zephyr and allow use of the
Picolibc module with C++ code, including using the minimal libc++ bits.

Signed-off-by: Keith Packard <keithp@keithp.com>
2023-01-20 09:03:25 +01:00
Chris Friedt
addbec9591 libc: minimal: stdio.h: define SEEK_SET, SEEK_CUR, SEEK_END
The `SEEK_SET`, `SEEK_CUR`, and `SEEK_END` constants are defined
in `<stdio.h>`, not in `<sys/stat.h>`.

Signed-off-by: Chris Friedt <cfriedt@meta.com>
2023-01-10 09:02:21 +09:00
Chris Friedt
8659e2f69e libc: minimal: include: move fcntl.h to posix
The `fcntl.h` header has never been a part of ISO C so move it to
`include/zephyr/posix`.

To ensure a smooth migration, a header was left in
`lib/libc/minimal/include` that prints a deprecation warning.

Users should either include `<zephyr/posix/fcntl.h>` or switch to
`CONFIG_POSIX_API=y`.

Signed-off-by: Chris Friedt <cfriedt@meta.com>
2023-01-10 09:02:21 +09:00
Chris Friedt
6f4e96bc24 libc: minimal: include: move sys/stat.h to posix
The `sys/stat.h` header has never been a part of ISO C so move it
to `zephyr/include/posix/sys/`.

To ensure a smooth migration, leave a stub header in
`lib/libc/minimal/include/sys/` that prints a deprecation warning
suggesting developers either include `<zephyr/posix/sys/stat.h>`
or use `CONFIG_POSIX_API=y`.

Signed-off-by: Chris Friedt <cfriedt@meta.com>
2023-01-10 09:02:21 +09:00
Stephanos Ioannidis
997f5edf1a lib: libc: picolibc: Clean up Kconfig configurations
This commit updates the Picolibc configurations to remove any
unnecessary defaults and dependencies and conform to the de-facto
standard convention across the Zephyr repository.

Signed-off-by: Stephanos Ioannidis <stephanos.ioannidis@nordicsemi.no>
2022-12-08 15:09:55 -05:00
Stephanos Ioannidis
c9c40d9465 lib: libc: Move newlib libc configs to lib/libc/newlib/Kconfig
This commit relocates the newlib libc configurations under the top-
level libc Kconfig to a new Kconfig under `lib/libc/newlib` for
improved organisation of the libc configurations.

Signed-off-by: Stephanos Ioannidis <stephanos.ioannidis@nordicsemi.no>
2022-12-08 15:09:55 -05:00
Stephanos Ioannidis
5efc0d51c8 lib: libc: Move minimal libc configs to lib/libc/minimal/Kconfig
This commit relocates the minimal libc configurations under the top-
level libc Kconfig to a new Kconfig under `lib/libc/minimal` for
improved organisation of the libc configurations.

Signed-off-by: Stephanos Ioannidis <stephanos.ioannidis@nordicsemi.no>
2022-12-08 15:09:55 -05:00
Stephanos Ioannidis
c3db8dc9e7 lib: libc: Clean up CMake script to use add_subdirectory_ifdef
This commit cleans up the top `CMakeLists.txt` for the libc directory
to use `add_subdirectory_ifdef` in order to make the code more
readable.

Signed-off-by: Stephanos Ioannidis <stephanos.ioannidis@nordicsemi.no>
2022-12-08 15:09:55 -05:00
Stephanos Ioannidis
82a902e5ea lib: newlib: Define _ANSI_SOURCE
This commit updates the Newlib integration to define `_ANSI_SOURCE`
in order to prevent Newlib from defining POSIX primitives in its
headers when GNU dialect is used (`-std=gnu*`).

Newlib `features.h` defines `_DEFAULT_SOURCE` when `__STRICT_ANSI__`
is not defined by GCC (i.e. when `-std=gnu*`), which results in the
Newlib headers defining POSIX primitives that are in conflict with the
POSIX primitives defined by Zephyr.

Newlib must not define POSIX primitives unless the feature test macros
such as `_POSIX_SOURCE`, `_GNU_SOURCE` and `_DEFAULT_SOURCE` are
explicitly defined.

Note that `-std=gnu` does not imply `_GNU_SOURCE` or `_DEFAULT_SOURCE`
because it is only supposed to instruct the compiler to use the GNU C
language dialect (i.e. GNU C language extensions).

Refer to the GitHub issue #52739 for more details.

Signed-off-by: Stephanos Ioannidis <stephanos.ioannidis@nordicsemi.no>
2022-12-05 11:02:36 +01:00
Keith Packard
d8d81c4a09 libc/picolibc: Remove unused POSIX-ish hooks
While reviewing the dependency between Picolibc POSIX APIs and Zephyr, I
found that the picolibc libc-hooks code copied a bunch of functions from
the newlib version which weren't needed. This required replacing a few
calls to the (now removed) '_write' hook with printk instead.

Signed-off-by: Keith Packard <keithp@keithp.com>
2022-11-02 06:49:32 -04:00
Keith Packard
25c378461e libc/picolibc: Set __LINUX_ERRNO_EXTENSIONS__ for picolibc
This makes sure extra errno values from Linux that Zephyr uses are
available.

Signed-off-by: Keith Packard <keithp@keithp.com>
2022-10-31 17:17:42 +09:00
Daniel Leung
cf23b312c3 lib: picolib: put stdio variables into libc partition
This adds the necessary modifier to the stdin/stdout/stderr
variables in picolib, and putting into the z_libc_partition.
This allows userspace applications to utilize these variables
for console I/O.

Fixes #51343

Signed-off-by: Daniel Leung <daniel.leung@intel.com>
2022-10-20 09:59:42 +02:00
Daniel Leung
6ee7294ac2 lib: picolib: move static to be the first modifier
Compliance check complains about static not being the first
modifier. So move them so there are no more complains
in the future.

Signed-off-by: Daniel Leung <daniel.leung@intel.com>
2022-10-20 09:59:42 +02:00
Stephanos Ioannidis
28b22b276a lib: libc: newlib: Make newlib nano variant optional
The newlib nano variant is currently enabled by default when
`CONFIG_NEWLIB_LIBC=y` and the selected toolchain-architecture
combination includes the newlib nano variant support, even if
`CONFIG_NEWLIB_LIBC_NANO` is not selected by the user.

When `CONFIG_NEWLIB_LIBC=y`, this results in the newlib nano variant
being selected for some architectures (e.g. ARC, ARM and RISC-V), while
the full variant is selected for the rest of the architectures.

The above behaviour is problematic because there exist functional
differences between the newlib full and nano variants (e.g. C99 format
modifiers such as `hh`, `ll`, `z`, `j` and `t` are not available in the
newlib nano variant), and this effectively leads to different level of
C standard support across different architectures when
`CONFIG_NEWLIB_LIBC=y`.

This commit fixes this problem by making the `CONFIG_NEWLIB_LIBC_NANO`
not `default y` and requiring its user to explicitly set this symbol to
`y` when they want to use the newlib nano variant.

Signed-off-by: Stephanos Ioannidis <stephanos.ioannidis@nordicsemi.no>
2022-10-19 16:02:51 +02:00