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>
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