fdcavalcanti commented on code in PR #20125:
URL: https://github.com/apache/nuttx/pull/20125#discussion_r4004812692
##########
arch/risc-v/src/common/espressif/Kconfig:
##########
@@ -238,6 +251,84 @@ config ESPRESSIF_REGION_PROTECTION
---help---
Configure the MPU to disable access to invalid memory regions.
+ Must be disabled in a protected build; esp_start.c fails the
build
+ if it is not. It only adds a second, redundant call to
+ esp_cpu_configure_region_protection() late in esp_start() -- the
+ regions have already been programmed from bootloader_init() by
then
+ -- and in a protected build the kernel owns the PMP and
re-describes
+ it during userspace initialisation, so the extra call is
pointless
+ at best and racy against that setup at worst.
+
+ This is enforced with a compile-time check rather than
+ "depends on !BUILD_PROTECTED". This symbol selects
ARCH_USE_MPU and
+ BUILD_PROTECTED depends on ARCH_USE_MPU, so a dependency on the
+ build type closes a loop that Kconfig resolves by making
+ BUILD_PROTECTED unsatisfiable -- which silently collapses the
whole
+ "Memory organization" choice for every board in the tree.
+
+config ESPRESSIF_KERNEL_OWNS_PMP
+ bool "Kernel owns the PMP configuration"
+ depends on ARCH_CHIP_ESP32P4
+ default n
+ select ARCH_USE_MPU
+ ---help---
+ Drop the HAL's esp_cpu_configure_region_protection() from the
build
+ and supply a NuttX build of the same code with the PMP lock bit
+ cleared. The region layout, and the PMA setup the SoC needs in
+ order to run at all, are unchanged; only the lock bit differs.
+
+ The HAL version sets the lock bit on every entry it writes, and
runs
+ from bootloader_init() before NuttX can intervene. PMP lock
bits
+ are irreversible without the Smepmp extension, which the
ESP32-P4
+ does not implement, so a protected build has to prevent the
locking
+ rather than undo it.
+
+ A protected build requires this and must set it explicitly in
its
+ defconfig; esp_start.c fails the build if the two disagree. It
is
+ deliberately not "default y if BUILD_PROTECTED": this symbol
selects
+ ARCH_USE_MPU, BUILD_PROTECTED depends on ARCH_USE_MPU, and a
default
+ conditioned on BUILD_PROTECTED closes that loop. Kconfig
resolves
+ the circularity by making BUILD_PROTECTED unsatisfiable, which
+ silently collapses the whole "Memory organization" choice for
every
+ board in the tree.
+
+ Enabling it on its own is legitimate only for bring-up: unlocked
+ entries do not constrain machine mode, so a flat build ends up
with
+ less protection than it would otherwise have.
+
+if BUILD_PROTECTED
+
+config ESPRESSIF_USER_IMAGE_OFFSET
Review Comment:
How is the MCUboot support?
This could clash against MCUboot similar option.
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