Fix two memory allocation bugs in label_boot_extension():

1. When label->fdtdir is not set, overlay_dir was used without any
   memory allocation.

2. When label->fdtdir is set, the allocation size was incorrect,
   using 'len' (just the fdtdir length) instead of 'dir_len' (which
   includes the trailing slash and null terminator).

Resolve both issues by moving the memory allocation and string
formatting outside the conditional block, resulting in clearer code
flow and correct sizing in all cases.

Closes: https://lists.denx.de/pipermail/u-boot/2025-November/602892.html
Addresses-Coverity-ID: 638558 Memory - illegal accesses (UNINIT)
Fixes: 935109cd9e97 ("boot: pxe_utils: Add extension board devicetree overlay support")
Signed-off-by: Kory Maincent (TI.com) <kory.maincent@bootlin.com>
Tested-by: Surkov Kirill <fanra3.tk@gmail.com>

Add support for scanning and applying extension board devicetree
overlays during PXE boot. After loading the main board devicetree,
the system now scans for available extension boards and applies their
overlays automatically.

This enables dynamic hardware configuration for systems with extension
boards during boot scenarios which are using pxe_utils.

Signed-off-by: Kory Maincent (TI.com) <kory.maincent@bootlin.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

In the case where parse_sliteral returns an error then label_name
will not have been assigned to. In order to prevent evaluating
label_name in this case add a check for the return value of parse_sliteral.

Signed-off-by: Andrew Goodbody <andrew.goodbody@linaro.org>

Add a file-type parameter to this function and update all users. Add a
proper comment to the function which we are here.

This will allow tracking of the file types loaded by the extlinux
bootmeth.

Signed-off-by: Simon Glass <sjg@chromium.org>

This function is exported, so document it in the header file. Drop the
duplicate comment in the C file.

Signed-off-by: Simon Glass <sjg@chromium.org>

This patch adds a new callback named need_reprint for menu.
The need_reprint will be called before printing the menu. If the
callback exists and returns FALSE, menu printing will be canceled.

This is very useful if the menu was not changed. It can save time
for serial-based menu to handle more input data.

Signed-off-by: Weijie Gao <weijie.gao@mediatek.com>
Reviewed-by: Daniel Golle <daniel@makrotopia.org>
Tested-by: Daniel Golle <daniel@makrotopia.org>

The "fallback" extlinux config option allows us to set an alternative
default boot option for when it has been detected that the default is
failing. Implement the logic required to boot from this option when
desired.

Signed-off-by: Martyn Welch <martyn.welch@collabora.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

When configured correctly, we can detect when boot fails after the boot
process has been handed over to the kernel through the use of U-Boot's
bootcount support. In some instances, such as when we are performing
atomic updates via a system such as OSTree, it is desirable to provide a
fallback option so that we can return to a previous (hopefully working)
state.

Add a "fallback" option to the supported extlinux configuration options
that points to a label like "default" so that we can utilise this in
later commits.

Signed-off-by: Martyn Welch <martyn.welch@collabora.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

Drop all duplicate newlines. No functional change.

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>

Tim Harvey <tharvey@gateworks.com> says:

This series will automatically add /chosen/kaslr-seed to the dt if
DM_RNG is enabled
during the boot process.

If RANDOMIZE_BASE is enabled in the Linux kernel instructing it to
randomize the virtual address at which the kernel image is loaded, it
expects entropy to be provided by the bootloader by populating
/chosen/kaslr-seed with a 64-bit value from source of entropy at boot.

If we have DM_RNG enabled populate this value automatically when
fdt_chosen is called. We skip this if ARMV8_SEC_FIRMWARE_SUPPORT
is enabled as its implementation uses a different source of entropy
that is not yet implemented as DM_RNG. We also skip this if
MEASURED_BOOT is enabled as in that case any modifications to the
dt will cause measured boot to fail (although there are many other
places the dt is altered).

As this fdt node is added elsewhere create a library function and
use it to deduplicate code. We will provide a parameter to overwrite
the node if present.

For our automatic injection, we will use the first rng device and
not overwrite if already present with a non-zero value (which may
have been populated by an earlier boot stage). This way if a board
specific ft_board_setup() function wants to customize this behavior
it can call fdt_kaslrseed with a rng device index of its choosing and
set overwrite true.

Note that the kalsrseed command (CMD_KASLRSEED) is likely pointless now
but left in place in case boot scripts exist that rely on this command
existing and returning success. An informational message is printed to
alert users of this command that it is likely no longer needed.

Note that the Kernel's EFI STUB only relies on EFI_RNG_PROTOCOL for
randomization and completely ignores the kaslr-seed for its own
randomness needs (i.e the randomization of the physical placement of
the kernel). It gets weeded out from the DTB that gets handed over via
efi_install_fdt() as it would also mess up the measured boot DTB TPM
measurements as well.