[PATCH master] Documentation: migration-2025.08.0: add note about W^X

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

CONFIG_ARM_MMU_PERMISSIONS was a relatively invasive change, so it
should be pointed out specifically to avoid users running into issues
with it.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 .../migration-guides/migration-2025.08.0.rst         | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/Documentation/migration-guides/migration-2025.08.0.rst b/Documentation/migration-guides/migration-2025.08.0.rst
index b40119ac672b..86412f25c36e 100644
--- a/Documentation/migration-guides/migration-2025.08.0.rst
+++ b/Documentation/migration-guides/migration-2025.08.0.rst
@@ -1,6 +1,18 @@
 Release v2025.08.0
 ==================
 
+W^X on ARM
+----------
+
+``CONFIG_ARM_MMU_PERMISSIONS=y`` is now the default and instructs barebox to map
+its memory regions with more restricted permissions: Data is no longer executable
+and code as well as read-only data is no longer writable.
+
+This can lead to breakage in code that had invalid assumptions beforehand,
+e.g. code expecting on-chip SRAMs to be executable or bogus code casting away
+const. Please report to upstream any issues that are resolved by disabling
+``CONFIG_ARM_MMU_PERMISSIONS``, so they can be properly fixed.
+
 Bootchooser
 -----------
 
-- 
2.47.3