[PATCH v6 5/6] arm/mpu: Introduce utility functions for the pr_t type

[Luca Fancellu <luca.fancellu@xxxxxxx>]

Introduce a few utility functions to manipulate and handle the
pr_t type.

Signed-off-by: Luca Fancellu <luca.fancellu@xxxxxxx>
---
v6 changes:
 - constify pointer arguments when needed, code style fix,
   add clarification comment in pr_set_limit
v5 changes:
 - Don't rely on bitfield and use the mask MPU_REGION_RES0 for
   pr_set_base and pr_set_limit to make it explicit. Fixed typos
   in commit message.
v4 changes:
 - Modify comment on top of the helpers. Clarify pr_set_limit
   takes exclusive address.
   Protected common code with #ifdef Arm64 until Arm32 is ready
   with pr_t
---
 xen/arch/arm/include/asm/mpu.h | 66 ++++++++++++++++++++++++++++++++++
 1 file changed, 66 insertions(+)

diff --git a/xen/arch/arm/include/asm/mpu.h b/xen/arch/arm/include/asm/mpu.h
index fb93b8b19d24..8f06ddac0fb1 100644
--- a/xen/arch/arm/include/asm/mpu.h
+++ b/xen/arch/arm/include/asm/mpu.h
@@ -23,6 +23,72 @@
 #define NUM_MPU_REGIONS_MASK    (NUM_MPU_REGIONS - 1)
 #define MAX_MPU_REGION_NR       NUM_MPU_REGIONS_MASK
 
+#ifndef __ASSEMBLY__
+
+#ifdef CONFIG_ARM_64
+/*
+ * Set base address of MPU protection region.
+ *
+ * @pr: pointer to the protection region structure.
+ * @base: base address as base of the protection region.
+ */
+static inline void pr_set_base(pr_t *pr, paddr_t base)
+{
+    pr->prbar.reg.base = ((base & ~MPU_REGION_RES0) >> MPU_REGION_SHIFT);
+}
+
+/*
+ * Set limit address of MPU protection region.
+ *
+ * @pr: pointer to the protection region structure.
+ * @limit: exclusive address as limit of the protection region.
+ */
+static inline void pr_set_limit(pr_t *pr, paddr_t limit)
+{
+    /* PRLAR_ELx.LIMIT expects inclusive limit */
+    pr->prlar.reg.limit = (((limit - 1) & ~MPU_REGION_RES0)
+                           >> MPU_REGION_SHIFT);
+}
+
+/*
+ * Access to get base address of MPU protection region.
+ * The base address shall be zero extended.
+ *
+ * @pr: pointer to the protection region structure.
+ * @return: Base address configured for the passed protection region.
+ */
+static inline paddr_t pr_get_base(const pr_t *pr)
+{
+    return (paddr_t)(pr->prbar.reg.base << MPU_REGION_SHIFT);
+}
+
+/*
+ * Access to get limit address of MPU protection region.
+ * The limit address shall be concatenated with 0x3f.
+ *
+ * @pr: pointer to the protection region structure.
+ * @return: Inclusive limit address configured for the passed protection 
region.
+ */
+static inline paddr_t pr_get_limit(const pr_t *pr)
+{
+    return (paddr_t)((pr->prlar.reg.limit << MPU_REGION_SHIFT)
+                     | ~MPU_REGION_MASK);
+}
+
+/*
+ * Check if the protection region is valid (enabled).
+ *
+ * @pr: pointer to the protection region structure.
+ * @return: True if the region is valid (enabled), false otherwise.
+ */
+static inline bool region_is_valid(const pr_t *pr)
+{
+    return pr->prlar.reg.en;
+}
+#endif /* CONFIG_ARM_64 */
+
+#endif /* __ASSEMBLY__ */
+
 #endif /* __ARM_MPU_H__ */
 
 /*
-- 
2.34.1