1 // SPDX-License-Identifier: GPL-2.0 2 3 #include <linux/efi.h> 4 #include <linux/screen_info.h> 5 6 #include <asm/efi.h> 7 8 #include "efistub.h" 9 10 /* 11 * There are two ways of populating the core kernel's struct screen_info via the stub: 12 * - using a configuration table, like below, which relies on the EFI init code 13 * to locate the table and copy the contents; 14 * - by linking directly to the core kernel's copy of the global symbol. 15 * 16 * The latter is preferred because it makes the EFIFB earlycon available very 17 * early, but it only works if the EFI stub is part of the core kernel image 18 * itself. The zboot decompressor can only use the configuration table 19 * approach. 20 */ 21 22 static efi_guid_t screen_info_guid = LINUX_EFI_SCREEN_INFO_TABLE_GUID; 23 24 struct screen_info *__alloc_screen_info(void) 25 { 26 struct screen_info *si; 27 efi_status_t status; 28 29 status = efi_bs_call(allocate_pool, EFI_ACPI_RECLAIM_MEMORY, 30 sizeof(*si), (void **)&si); 31 32 if (status != EFI_SUCCESS) 33 return NULL; 34 35 memset(si, 0, sizeof(*si)); 36 37 status = efi_bs_call(install_configuration_table, 38 &screen_info_guid, si); 39 if (status == EFI_SUCCESS) 40 return si; 41 42 efi_bs_call(free_pool, si); 43 return NULL; 44 } 45 46 void free_screen_info(struct screen_info *si) 47 { 48 if (!si) 49 return; 50 51 efi_bs_call(install_configuration_table, &screen_info_guid, NULL); 52 efi_bs_call(free_pool, si); 53 } 54