xtensa: mpu: make sure write to MPU regions is atomic (5d466aad) · Commits · Wenxi XU / zephyr

This adds a spinlock to make sure writing to hardware MPU regions is atomic, and cannot be interrupted until all regions are written to hardware. Signed-off-by:

Daniel Leung <daniel.leung@intel.com> (cherry picked from commit )

arch/xtensa/core/mpu.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -33,6 +33,9 @@ extern char _heap_start[];
		/** MPU foreground map for kernel mode. */
		static struct xtensa_mpu_map xtensa_mpu_map_fg_kernel;

		/** Make sure write to the MPU region is atomic. */
		static struct k_spinlock xtensa_mpu_lock;

		/*
		* Additional information about the MPU maps: foreground and background
		* maps.
		@@ -629,6 +632,9 @@ void xtensa_mpu_map_write(struct xtensa_mpu_map *map)
		#endif
		{
		int entry;
		k_spinlock_key_t key;

		key = k_spin_lock(&xtensa_mpu_lock);

		#ifdef CONFIG_USERSPACE
		struct xtensa_mpu_map *map = thread->arch.mpu_map;
		@@ -652,6 +658,8 @@ void xtensa_mpu_map_write(struct xtensa_mpu_map *map)
		__asm__ volatile("wptlb %0, %1\n\t"
		: : "a"(map->entries[entry].at), "a"(map->entries[entry].as));
		}

		k_spin_unlock(&xtensa_mpu_lock, key);
		}

		/**

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