IEE: arm64: mmu: Improve IEE data segment mapping logic

Enhance the kernel data segment mapping logic in the map_kernel()
function to properly handle IEE initialization data segments.

Key improvements:
 *Add size validation for IEE data segments by calculating iee_data_size
 *Only create separate mappings when IEE init data is actually present
 *Add informative log message when no IEE init data exists
 *Fix code structure and conditional logic for better readability and correctness

This change ensures that the kernel data mapping strategy is
appropriately chosen based on the actual presence of IEE
initialization data, avoiding unnecessary complexity when IEE data
segments are empty while maintaining proper functionality when they
are present.

Tested-by: Jun Zhan <[email protected]>
Co-developed-by: Jun Zhan <[email protected]>
Signed-off-by: Jun Zhan <[email protected]>
Signed-off-by: WangYuli <[email protected]>

Author: WangYuli

arch/arm64/mm/mmu.c

@@ -791,10 +791,18 @@ static void __init map_kernel(pgd_t *pgdp)
 				   &vmlinux_initdata, 0, VM_NO_GUARD);
 #ifdef CONFIG_IEE
 		if (haoc_enabled) {
-			map_kernel_segment(pgdp, _data, iee_init_data_end, PAGE_KERNEL,
-					 &vmlinux_iee_init_data, NO_CONT_MAPPINGS | NO_BLOCK_MAPPINGS, VM_NO_GUARD);
-			map_kernel_segment(pgdp, iee_init_data_end, _end, PAGE_KERNEL, &vmlinux_data, 0, 0);
-			} else
+			unsigned long iee_data_size = (unsigned long)iee_init_data_end - (unsigned long)_data;
+
+			if (iee_data_size > 0) {
+				// 只有当IEE数据段非空时才创建分离的映射
+				map_kernel_segment(pgdp, _data, iee_init_data_end, PAGE_KERNEL,
+						 &vmlinux_iee_init_data, NO_CONT_MAPPINGS | NO_BLOCK_MAPPINGS, VM_NO_GUARD);
+				map_kernel_segment(pgdp, iee_init_data_end, _end, PAGE_KERNEL, &vmlinux_data, 0, 0);
+			} else {
+				pr_info("IEE: No IEE init data, using standard data mapping\n");
+				map_kernel_segment(pgdp, _data, _end, PAGE_KERNEL, &vmlinux_data, 0, 0);
+			}
+		} else
 			map_kernel_segment(pgdp, _data, _end, PAGE_KERNEL, &vmlinux_data, 0, 0);
 #else	
 		map_kernel_segment(pgdp, _data, _end, PAGE_KERNEL, &vmlinux_data, 0, 0);