1 // SPDX-License-Identifier: GPL-2.0
48 	 * EFI systems may not provide legacy ROM. The memory may not be mapped  in find_trampoline_placement()
51 	 * Only look for values in the legacy ROM for non-EFI system.  in find_trampoline_placement()
53 	signature = (char *)&boot_params_ptr->efi_info.efi_loader_signature;  in find_trampoline_placement()
69 	for (i = boot_params_ptr->e820_entries - 1; i >= 0; i--) {  in find_trampoline_placement()
72 		entry = &boot_params_ptr->e820_table[i];  in find_trampoline_placement()
75 		if (bios_start <= entry->addr)  in find_trampoline_placement()
78 		/* Skip non-RAM entries. */  in find_trampoline_placement()
79 		if (entry->type != E820_TYPE_RAM)  in find_trampoline_placement()
83 		if (bios_start > entry->addr + entry->size)  in find_trampoline_placement()
84 			new = entry->addr + entry->size;  in find_trampoline_placement()
86 		/* Keep bios_start page-aligned. */  in find_trampoline_placement()
90 		if (new - TRAMPOLINE_32BIT_SIZE < entry->addr)  in find_trampoline_placement()
94 		if (new - TRAMPOLINE_32BIT_SIZE > bios_start)  in find_trampoline_placement()
102 	return bios_start - TRAMPOLINE_32BIT_SIZE;  in find_trampoline_placement()
118 	 *   - if the kernel supports 5-level paging: CONFIG_X86_5LEVEL=y  in configure_5level_paging()
119 	 *   - if user asked to disable 5-level paging: no5lvl in cmdline  in configure_5level_paging()
120 	 *   - if the machine supports 5-level paging:  in configure_5level_paging()
132 		/* Initialize variables for 5-level paging */  in configure_5level_paging()
159 	 * Avoid the need for a stack in the 32-bit trampoline code, by using  in configure_5level_paging()
171 	 * from 4- to 5-level paging or vice versa.  in configure_5level_paging()
176 		 * For 4- to 5-level paging transition, set up current CR3 as  in configure_5level_paging()
177 		 * the first and the only entry in a new top-level page table.  in configure_5level_paging()
184 		 * For 5- to 4-level paging transition, copy page table pointed  in configure_5level_paging()
185 		 * by first entry in the current top-level page table as our  in configure_5level_paging()
186 		 * new top-level page table.  in configure_5level_paging()