nuttx/arch
Marco Casaroli c9cd9db25f tools/nxflat: Add an Apache-licensed NXFLAT converter.
ldnxflat is the last piece of the NXFLAT toolchain that NuttX cannot carry.
It descends from elf2flt through four sets of copyright holders, so it is GPL
by that descent and not merely by its libbfd dependency.  This is a new
implementation, written from include/nxflat.h, from what binfmt/libnxflat does
with the container, and from the ELF specification.  The relocation arithmetic
is that of libs/libc/machine/arm/armv7-m/arch_elf.c, which the ELF loader runs
on the target for the same relocations, and which brings R_ARM_TARGET1 with
it.

NXFLAT is not an ARM format.  Its loader only adds a base to a 32-bit word, so
the segments, the GOT, the relocation records and the header are common to
every architecture.  An architecture supplies a table entry, an entry-point
convention and a relocation handler; an object for a machine with no entry is
refused by name.

The GOT is built here, because ld -r emits none: one entry per symbol that a
GOT-relative reference names, at the start of D-Space, each with a relocation
record of its own.  An entry may hold a function, which is what makes a
function pointer reached through the GOT work.

Two defects of the out-of-tree tool do not survive.  A GOT entry naming a .bss
object lost its section's address and pointed at the start of D-Space, the GOT
itself, so on lm3s6965-ek:qemu-nxflat the longjmp test panics with PC 0 and
the five tests after it never run.  The alignment gap before .bss went missing
from h_bssend as well, leaving D-Space short.

The tool is built and named like the rest of the toolchain.  Makefile.host
builds it, Unix.mk makes a configuration that sets CONFIG_NXFLAT depend on it
beside mknxflat, and LDNXFLAT points at the tool in the tree rather than one
on PATH.

All eight C modules of apps/examples/nxflat/tests convert and run to
completion under qemu-system-arm -M lm3s6965evb.

Assisted-by: Claude Opus 5 (1M context) <noreply@anthropic.com>
Signed-off-by: Marco Casaroli <marco.casaroli@gmail.com>
2026-09-27 11:25:12 -03:00
..
arm tools/nxflat: Add an Apache-licensed NXFLAT converter. 2026-09-27 11:25:12 -03:00
arm64 arch/arm64/imx9: add an ELE-backed /dev/random driver. 2026-09-27 11:02:13 -03:00
avr arch, boards, cmake: Build C++ ELF modules without __cxa_atexit. 2026-09-04 15:44:24 -03:00
ceva arch/atomic: remove up_testset in spinlock 2026-09-08 08:58:54 +08:00
dummy
hc
mips arch, boards, cmake: Build C++ ELF modules without __cxa_atexit. 2026-09-04 15:44:24 -03:00
misoc arch, boards, cmake: Build C++ ELF modules without __cxa_atexit. 2026-09-04 15:44:24 -03:00
or1k arch, boards, cmake: Build C++ ELF modules without __cxa_atexit. 2026-09-04 15:44:24 -03:00
renesas nuttx/libc: refine the atomic related Kconfig 2026-08-24 13:20:45 +08:00
risc-v arch/risc-v/esp32c2: add ESP32-C2 chip support 2026-09-25 21:08:00 +08:00
sim arch/sim: buffer several mouse reports 2026-09-25 10:36:28 +02:00
sparc arch/atomic: remove up_testset in spinlock 2026-09-08 08:58:54 +08:00
tricore arch/atomic: remove up_testset in spinlock 2026-09-08 08:58:54 +08:00
x86 arch/x86: Add -P to CPP to suppress linemarkers. 2026-09-17 16:21:59 +08:00
x86_64 arch/x86_64: Implement up_addrenv_fork() and provide POSIX fork(). 2026-09-24 18:02:36 -03:00
xtensa arch/xtensa: Provide POSIX fork() on the ESP32-S3. 2026-09-26 11:13:57 -03:00
z16
z80
CMakeLists.txt
Kconfig arch/xtensa: Provide POSIX fork() on the ESP32-S3. 2026-09-26 11:13:57 -03:00