diff --git a/arch/riscv/core/pmp.c b/arch/riscv/core/pmp.c
index ca5e5a49d5a74..d91b43e884051 100644
--- a/arch/riscv/core/pmp.c
+++ b/arch/riscv/core/pmp.c
@@ -335,11 +335,13 @@ static void write_pmp_entries(unsigned int start, unsigned int end,
 	ARRAY_SIZE(thread->arch.u_mode_pmpaddr_regs)
 
 /*
- * This is used to seed thread PMP copies with global m-mode cfg entries
- * sharing the same cfg register. Locked entries aren't modifiable but
+ * Stores the initial values of the pmpcfg CSRs, covering all global
+ * m-mode PMP entries. This array is sized to hold all pmpcfg registers
+ * necessary for CONFIG_PMP_SLOTS. It is used to seed the per-thread
+ * PMP configuration copies. Locked entries aren't modifiable but
  * we could have non-locked entries here too.
  */
-static unsigned long global_pmp_cfg[1];
+static unsigned long global_pmp_cfg[CONFIG_PMP_SLOTS / PMPCFG_STRIDE];
 static unsigned long global_pmp_last_addr;
 
 /* End of global PMP entry range */
@@ -432,12 +434,12 @@ void z_riscv_pmp_init(void)
 	/* Make sure secondary CPUs produced the same values */
 	if (global_pmp_end_index != 0) {
 		__ASSERT(global_pmp_end_index == index, "");
-		__ASSERT(global_pmp_cfg[0] == pmp_cfg[0], "");
+		__ASSERT(memcmp(pmp_cfg, global_pmp_cfg, sizeof(global_pmp_cfg)) == 0, "");
 		__ASSERT(global_pmp_last_addr == pmp_addr[index - 1], "");
 	}
 #endif
 
-	global_pmp_cfg[0] = pmp_cfg[0];
+	memcpy(global_pmp_cfg, pmp_cfg, sizeof(pmp_cfg));
 	global_pmp_last_addr = pmp_addr[index - 1];
 	global_pmp_end_index = index;
 
@@ -457,9 +459,9 @@ static inline unsigned int z_riscv_pmp_thread_init(unsigned long *pmp_addr,
 	ARG_UNUSED(index_limit);
 
 	/*
-	 * Retrieve pmpcfg0 partial content from global entries.
+	 * Retrieve the pmpcfg register with partial content from global entries.
 	 */
-	pmp_cfg[0] = global_pmp_cfg[0];
+	memcpy(pmp_cfg, global_pmp_cfg, sizeof(global_pmp_cfg));
 
 	/*
 	 * Retrieve the pmpaddr value matching the last global PMP slot.
@@ -520,7 +522,7 @@ void z_riscv_pmp_stackguard_enable(struct k_thread *thread)
 
 	/* Write our m-mode MPP entries */
 	write_pmp_entries(global_pmp_end_index, thread->arch.m_mode_pmp_end_index,
-			  false /* no need to clear to the end */,
+			  true,
 			  PMP_M_MODE(thread));
 
 	if (PMP_DEBUG_DUMP) {
diff --git a/include/zephyr/arch/riscv/thread.h b/include/zephyr/arch/riscv/thread.h
index 08f14b61cebf7..c6ca4d7ae4162 100644
--- a/include/zephyr/arch/riscv/thread.h
+++ b/include/zephyr/arch/riscv/thread.h
@@ -81,8 +81,8 @@ struct _thread_arch {
 #endif
 #ifdef CONFIG_PMP_STACK_GUARD
 	unsigned int m_mode_pmp_end_index;
-	unsigned long m_mode_pmpaddr_regs[PMP_M_MODE_SLOTS];
-	unsigned long m_mode_pmpcfg_regs[PMP_M_MODE_SLOTS / sizeof(unsigned long)];
+	unsigned long m_mode_pmpaddr_regs[CONFIG_PMP_SLOTS];
+	unsigned long m_mode_pmpcfg_regs[CONFIG_PMP_SLOTS / sizeof(unsigned long)];
 #endif
 };