CONFIG_SRAM_REGION_PERMISSIONS
Assign appropriate permissions to kernel areas in SRAM
Type: bool
Help
This option indicates that memory protection hardware
is present, enabled, and regions have been configured at boot for memory
ranges within the kernel image.
If this option is turned on, certain areas of the kernel image will
have the following access policies applied for all threads, including
supervisor threads:
1) All program text will be have read-only, execute memory permission
2) All read-only data will have read-only permission, and execution
disabled if the hardware supports it.
3) All other RAM addresses will have read-write permission, and
execution disabled if the hardware supports it.
Options such as USERSPACE or HW_STACK_PROTECTION may additionally
impose additional policies on the memory map, which may be global
or local to the current running thread.
This option may consume additional memory to satisfy memory protection
hardware alignment constraints.
If this option is disabled, the entire kernel will have default memory
access permissions set, typically read/write/execute. It may be desirable
to turn this off on MMU systems which are using the MMU for demand
paging, do not need memory protection, and would rather not use up
RAM for the alignment between regions.
Default
y
Kconfig definition
At <Zephyr>/arch/Kconfig:812
Included via <Zephyr>/Kconfig:8 → <Zephyr>/Kconfig.zephyr:39
Menu path: (Top)
config SRAM_REGION_PERMISSIONS
bool "Assign appropriate permissions to kernel areas in SRAM"
default y
depends on MMU || MPU
help
This option indicates that memory protection hardware
is present, enabled, and regions have been configured at boot for memory
ranges within the kernel image.
If this option is turned on, certain areas of the kernel image will
have the following access policies applied for all threads, including
supervisor threads:
1) All program text will be have read-only, execute memory permission
2) All read-only data will have read-only permission, and execution
disabled if the hardware supports it.
3) All other RAM addresses will have read-write permission, and
execution disabled if the hardware supports it.
Options such as USERSPACE or HW_STACK_PROTECTION may additionally
impose additional policies on the memory map, which may be global
or local to the current running thread.
This option may consume additional memory to satisfy memory protection
hardware alignment constraints.
If this option is disabled, the entire kernel will have default memory
access permissions set, typically read/write/execute. It may be desirable
to turn this off on MMU systems which are using the MMU for demand
paging, do not need memory protection, and would rather not use up
RAM for the alignment between regions.
(The ‘depends on’ condition includes propagated dependencies from ifs and menus.)