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authorJonathan Austin <jonathan.austin@arm.com>2013-02-22 18:56:04 +0000
committerJonathan Austin <jonathan.austin@arm.com>2013-06-17 15:13:03 +0100
commit801bb21c600161c8626d7d9cb649be869ee4dbbe (patch)
treed4418d0f772af88dbfbaa8a4019acc92c9a79df0
parenteb08375ea66e63c5e11dea69b43c5633d531ce81 (diff)
ARM: mpu: Allow enabling of the MPU via kconfig
Allows the user to select MPU support when compiling for ARM processors that support the PMSAv7. This ensures that CONFIG_SMP depends on the MPU in the case that no MMU is present. CONFIG_SMP_ON_UP is not implemented for nommu, so introduce an MMU dependency there. Signed-off-by: Jonathan Austin <jonathan.austin@arm.com> Reviewed-by: Will Deacon <will.deacon@arm.com>
-rw-r--r--arch/arm/Kconfig4
-rw-r--r--arch/arm/Kconfig-nommu11
2 files changed, 13 insertions, 2 deletions
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 5543d36c2834..ec38cacb3d08 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1414,7 +1414,7 @@ config SMP
depends on CPU_V6K || CPU_V7
depends on GENERIC_CLOCKEVENTS
depends on HAVE_SMP
- depends on MMU
+ depends on MMU || ARM_MPU
select USE_GENERIC_SMP_HELPERS
help
This enables support for systems with more than one CPU. If you have
@@ -1435,7 +1435,7 @@ config SMP
config SMP_ON_UP
bool "Allow booting SMP kernel on uniprocessor systems (EXPERIMENTAL)"
- depends on SMP && !XIP_KERNEL
+ depends on SMP && !XIP_KERNEL && MMU
default y
help
SMP kernels contain instructions which fail on non-SMP processors.
diff --git a/arch/arm/Kconfig-nommu b/arch/arm/Kconfig-nommu
index c859495da480..db597e1c7572 100644
--- a/arch/arm/Kconfig-nommu
+++ b/arch/arm/Kconfig-nommu
@@ -50,3 +50,14 @@ config REMAP_VECTORS_TO_RAM
Otherwise, say 'y' here. In this case, the kernel will require
external support to redirect the hardware exception vectors to
the writable versions located at DRAM_BASE.
+
+config ARM_MPU
+ bool 'Use the ARM v7 PMSA Compliant MPU'
+ default y
+ help
+ Some ARM systems without an MMU have instead a Memory Protection
+ Unit (MPU) that defines the type and permissions for regions of
+ memory.
+
+ If your CPU has an MPU then you should choose 'y' here unless you
+ know that you do not want to use the MPU.