nuttx/libs/libc/misc/lib_nxflat.c
Marco Casaroli 08c0cce0d9 libs/libc: Define the NXFLAT ABI marker in libc.
Every NXFLAT module imports __nxflat_abi_v2, and the loader resolves it
against the symbol table exec() is given, like any other import.  It was
defined in binfmt/libnxflat, which is enough for a flat build, where the
firmware and the applications are one image.

In a protected build the table comes from the application, in the user
image, which cannot see a kernel symbol: the user image fails to link with
an undefined reference to __nxflat_abi_v2 as soon as an application
generates its table from the modules' imports, as examples/nxflat does.  A
kernel build is the same, with one image per process.

libc is linked into each of those images, so the marker is defined there
now.  Nothing else changes: its value is still never used.

On mps3-an547:knsh under QEMU with CONFIG_NXFLAT and examples/nxflat, the
user image links, and errno, hello, mutex, pthread and struct run.
lm3s6965-ek:qemu-nxflat still runs every module to the end.

Assisted-by: Claude Code:claude-opus-5-5
Signed-off-by: Marco Casaroli <marco.casaroli@gmail.com>
2026-09-28 16:45:48 -03:00

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1.8 KiB
C

/****************************************************************************
* libs/libc/misc/lib_nxflat.c
*
* SPDX-License-Identifier: Apache-2.0
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <nxflat.h>
/****************************************************************************
* Public Data
****************************************************************************/
/* The module ABI marker. Every module built by mknxflat imports it, so it
* must be in whatever image supplies the symbol table to exec(): in libc,
* both halves of a protected or kernel build have it. Only its presence
* matters.
*/
void *NXFLAT_ABI_MARKER;
/****************************************************************************
* Public Functions
****************************************************************************/