linker: correct linker script _flash_used calculation
Linker scripts contains a `.last_section` section that is placed in rom
region as NOLOAD for the purpose of retrieve the actual number of bytes
contained in the image. See d85efe0b10f1f8ed4b854717f994062a4bbffe26
However, a previous section may cause the location counter to be
incremented for alignment purposes. This can result in the size of the
image to be 0x10FA but location counter to be 0x1100 because it has been
aligned for next section placement.
Therefore, two new Kconfig settings are introduced.
Those settings request the linker to will write a pattern in
`.last_section`. Together with removing NOLOAD and writing a patten to
the section then we ensure that data is written after alignment of
location counter, and thereby forces the image size to be in sync with
the location counter.
The default pattern used will be 0xE015 (end of last section).
Some systems may fill up the flash completely, or simply write data at
the end of the flash, which in both cases can result in overflow.
Therefore, the new settings can be disabled.
Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>
6 files changed
