arch/riscv: Refactor PMP configuration reading

Factor out the logic for reading PMP configuration registers (pmpcfgX)
from dump_pmp_regs into a new static inline helper function,
z_riscv_pmp_read_config.

This new function encapsulates the architecture-specific (RV32/RV64)
and slot-count-specific reads of the pmpcfg CSRs, improving code
organization and potential reusability.

Signed-off-by: Firas Sammoura <[email protected]>

Author: fsammoura1980

arch/riscv/core/pmp.c

@@ -104,34 +104,53 @@ static void print_pmp_entries(unsigned int pmp_start, unsigned int pmp_end,
 	}
 }
 
-static void dump_pmp_regs(const char *banner)
+/**
+ * @brief Reads the PMP configuration CSRs (pmpcfgX) based on architecture and slot count.
+ *
+ * This helper function abstracts the logic required to read the correct CSRs
+ * (pmpcfg0, pmpcfg1, pmpcfg2, pmpcfg3) depending on whether the system is
+ * 32-bit or 64-bit and the total number of PMP slots configured.
+ *
+ * @param pmp_cfg Pointer to the array where the CSR contents will be stored.
+ * @param pmp_cfg_size The size of the pmp_cfg array, measured in unsigned long entries.
+ */
+static inline void z_riscv_pmp_read_config(unsigned long *pmp_cfg, size_t pmp_cfg_size)
 {
-	unsigned long pmp_addr[CONFIG_PMP_SLOTS];
-	unsigned long pmp_cfg[CONFIG_PMP_SLOTS / PMPCFG_STRIDE];
-
-#define PMPADDR_READ(x) pmp_addr[x] = csr_read(pmpaddr##x)
-
-	FOR_EACH(PMPADDR_READ, (;), 0, 1, 2, 3, 4, 5, 6, 7);
-#if CONFIG_PMP_SLOTS > 8
-	FOR_EACH(PMPADDR_READ, (;), 8, 9, 10, 11, 12, 13, 14, 15);
-#endif
-
-#undef PMPADDR_READ
+	__ASSERT(num_slots == (size_t)(CONFIG_PMP_SLOTS / PMPCFG_STRIDE),
+		 "Invalid PMP config array size");
 
 #ifdef CONFIG_64BIT
+	/* RV64: pmpcfg0 holds entries 0-7; pmpcfg2 holds entries 8-15. */
 	pmp_cfg[0] = csr_read(pmpcfg0);
 #if CONFIG_PMP_SLOTS > 8
 	pmp_cfg[1] = csr_read(pmpcfg2);
 #endif
 #else
+	/* RV32: Each pmpcfg register holds 4 entries. */
 	pmp_cfg[0] = csr_read(pmpcfg0);
 	pmp_cfg[1] = csr_read(pmpcfg1);
 #if CONFIG_PMP_SLOTS > 8
 	pmp_cfg[2] = csr_read(pmpcfg2);
 	pmp_cfg[3] = csr_read(pmpcfg3);
 #endif
 #endif
+}
+
+static void dump_pmp_regs(const char *banner)
+{
+	unsigned long pmp_addr[CONFIG_PMP_SLOTS];
+	unsigned long pmp_cfg[CONFIG_PMP_SLOTS / PMPCFG_STRIDE];
+
+#define PMPADDR_READ(x) pmp_addr[x] = csr_read(pmpaddr##x)
+
+	FOR_EACH(PMPADDR_READ, (;), 0, 1, 2, 3, 4, 5, 6, 7);
+#if CONFIG_PMP_SLOTS > 8
+	FOR_EACH(PMPADDR_READ, (;), 8, 9, 10, 11, 12, 13, 14, 15);
+#endif
+
+#undef PMPADDR_READ
 
+	z_riscv_pmp_read_config(pmp_cfg, (size_t)(CONFIG_PMP_SLOTS / PMPCFG_STRIDE));
 	print_pmp_entries(0, CONFIG_PMP_SLOTS, pmp_addr, pmp_cfg, banner);
 }