projects / linux-block.git / blame
| Commit | Line | Data |
|---|---|---|
| b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
| 5dcd14ec PA |
2 | #ifndef _ASM_X86_BOOTPARAM_UTILS_H |
| 3 | #define _ASM_X86_BOOTPARAM_UTILS_H | |
| 4 | ||
| 5 | #include <asm/bootparam.h> | |
| 6 | ||
| 7 | /* | |
| 8 | * This file is included from multiple environments. Do not | |
| 9 | * add completing #includes to make it standalone. | |
| 10 | */ | |
| 11 | ||
| 12 | /* | |
| 13 | * Deal with bootloaders which fail to initialize unknown fields in | |
| 14 | * boot_params to zero. The list fields in this list are taken from | |
| 15 | * analysis of kexec-tools; if other broken bootloaders initialize a | |
| 16 | * different set of fields we will need to figure out how to disambiguate. | |
| 17 | * | |
| 2e604c0f JB |
18 | * Note: efi_info is commonly left uninitialized, but that field has a |
| 19 | * private magic, so it is better to leave it unchanged. | |
| 5dcd14ec PA |
20 | */ |
| 21 | static void sanitize_boot_params(struct boot_params *boot_params) | |
| 22 | { | |
| 3c4aff6b PJ |
23 | /* |
| 24 | * IMPORTANT NOTE TO BOOTLOADER AUTHORS: do not simply clear | |
| 25 | * this field. The purpose of this field is to guarantee | |
| 26 | * compliance with the x86 boot spec located in | |
| 27 | * Documentation/x86/boot.txt . That spec says that the | |
| 28 | * *whole* structure should be cleared, after which only the | |
| 29 | * portion defined by struct setup_header (boot_params->hdr) | |
| 30 | * should be copied in. | |
| 31 | * | |
| 32 | * If you're having an issue because the sentinel is set, you | |
| 33 | * need to change the whole structure to be cleared, not this | |
| 34 | * (or any other) individual field, or you will soon have | |
| 35 | * problems again. | |
| 36 | */ | |
| 5dcd14ec | 37 | if (boot_params->sentinel) { |
| 3c4aff6b | 38 | /* fields in boot_params are left uninitialized, clear them */ |
| d55e37bb | 39 | memset(&boot_params->ext_ramdisk_image, 0, |
| 2e604c0f | 40 | (char *)&boot_params->efi_info - |
| d55e37bb | 41 | (char *)&boot_params->ext_ramdisk_image); |
| 5dcd14ec PA |
42 | memset(&boot_params->kbd_status, 0, |
| 43 | (char *)&boot_params->hdr - | |
| 44 | (char *)&boot_params->kbd_status); | |
| 45 | memset(&boot_params->_pad7[0], 0, | |
| 46 | (char *)&boot_params->edd_mbr_sig_buffer[0] - | |
| 47 | (char *)&boot_params->_pad7[0]); | |
| 48 | memset(&boot_params->_pad8[0], 0, | |
| 49 | (char *)&boot_params->eddbuf[0] - | |
| 50 | (char *)&boot_params->_pad8[0]); | |
| 51 | memset(&boot_params->_pad9[0], 0, sizeof(boot_params->_pad9)); | |
| 52 | } | |
| 53 | } | |
| 54 | ||
| 55 | #endif /* _ASM_X86_BOOTPARAM_UTILS_H */ |