1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 3 #include <acpi/acpi.h> 4 #include <cbmem.h> 5 #include <console/console.h> 6 #include <cpu/x86/smm.h> 7 #include <string.h> 8 backup_default_smm_area(void)9void *backup_default_smm_area(void) 10 { 11 void *save_area; 12 const void *default_smm = (void *)SMM_DEFAULT_BASE; 13 14 if (!CONFIG(HAVE_ACPI_RESUME)) 15 return NULL; 16 17 /* 18 * The buffer needs to be preallocated regardless. In the non-resume 19 * path it will be allocated for handling resume. Note that cbmem_add() 20 * does a find before the addition. 21 */ 22 save_area = cbmem_add(CBMEM_ID_SMM_SAVE_SPACE, SMM_DEFAULT_SIZE); 23 24 if (save_area == NULL) { 25 printk(BIOS_DEBUG, "SMM save area not added.\n"); 26 return NULL; 27 } 28 29 /* Only back up the area on S3 resume. */ 30 if (acpi_is_wakeup_s3()) { 31 memcpy(save_area, default_smm, SMM_DEFAULT_SIZE); 32 return save_area; 33 } 34 35 /* 36 * Not the S3 resume path. No need to restore memory contents after 37 * SMM relocation. 38 */ 39 return NULL; 40 } 41 restore_default_smm_area(void * smm_save_area)42void restore_default_smm_area(void *smm_save_area) 43 { 44 void *default_smm = (void *)SMM_DEFAULT_BASE; 45 46 if (smm_save_area == NULL) 47 return; 48 49 memcpy(default_smm, smm_save_area, SMM_DEFAULT_SIZE); 50 } 51