Initialize global PMP configuration state

Adds centralized management of PMP hardware state through a global
configuration instance. This enables the memory protection subsystem
to track and coordinate PMP register usage across the kernel without
requiring each component to maintain its own state.

Provides controlled access to the configuration through a dedicated
accessor function, maintaining encapsulation while supporting dynamic
region allocation and eviction during task switching.

Author: HeatCrab

arch/riscv/pmp.c

@@ -29,6 +29,14 @@ static const mempool_t kernel_mempools[] = {
 #define KERNEL_MEMPOOL_COUNT \
     (sizeof(kernel_mempools) / sizeof(kernel_mempools[0]))
 
+/* Global PMP configuration (shadow of hardware state) */
+static pmp_config_t pmp_global_config;
+
+pmp_config_t *pmp_get_config(void)
+{
+    return &pmp_global_config;
+}
+
 /* Initialize PMP from Memory Pools
  *
  * Configures PMP regions based on static memory pool definitions.

arch/riscv/pmp.h

@@ -6,11 +6,9 @@
 
 #pragma once
 
+#include <sys/memprot.h>
 #include <types.h>
 
-/* Forward declaration */
-typedef struct mempool mempool_t;
-
 /* PMP Region Priority Levels (lower value = higher priority)
  *
  * Used for eviction decisions when hardware PMP regions are exhausted.
@@ -43,6 +41,9 @@ typedef struct {
 
 /* PMP Management Functions */
 
+/* Returns pointer to global PMP configuration */
+pmp_config_t *pmp_get_config(void);
+
 /* Initializes the PMP hardware and configuration state.
  * @config : Pointer to pmp_config_t structure to be initialized.
  * Returns 0 on success, or negative error code on failure.