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