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arch: arm: mpu: no dynamic MPU re-program in swap if not required

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Dynamic MPU regions are used in build configurations with User
mode or MPU-based stack-overflow guards. If these features are
disabled, we skip calling the ARM function for re-programming
the MPU peripheral during context-switch. We also skip doing
this when jumping to main thread (although this brings limited
performace gain as it is called once in the boot cycle)

Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
This commit is contained in:
Ioannis Glaropoulos 2020-01-30 18:45:23 +01:00 • committed by Carles Cufí
commit 8345434a24
2 changed files with 3 additions and 3 deletions
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4
arch/arm/core/aarch32/swap_helper.S
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@ -198,7 +198,7 @@ out_fp_endif:
cpsie i
_thread_irq_disabled:
#if defined(CONFIG_ARM_MPU)
#if defined(CONFIG_MPU_STACK_GUARD) || defined(CONFIG_USERSPACE)
/* Re-program dynamic memory map */
push {r2,lr}
mov r0, r2
@ -278,7 +278,7 @@ in_fp_endif:
isb
#endif
#if defined (CONFIG_ARM_MPU)
#if defined(CONFIG_MPU_STACK_GUARD) || defined(CONFIG_USERSPACE)
/* Re-program dynamic memory map */
push {r2,lr}
mov r0, r2 /* _current thread */

2
arch/arm/core/aarch32/thread.c
View file

@ -404,7 +404,7 @@ void arch_switch_to_main_thread(struct k_thread *main_thread,
/* the ready queue cache already contains the main thread */
#ifdef CONFIG_ARM_MPU
#if defined(CONFIG_MPU_STACK_GUARD) || defined(CONFIG_USERSPACE)
/*
* If stack protection is enabled, make sure to set it
* before jumping to thread entry function