1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2016 Linaro Ltd <ard.biesheuvel@linaro.org> 4 */ 5 6 #include <linux/cache.h> 7 #include <linux/init.h> 8 #include <linux/printk.h> 9 10 #include <asm/cpufeature.h> 11 #include <asm/memory.h> 12 13 u16 __initdata memstart_offset_seed; 14 15 bool __ro_after_init __kaslr_is_enabled = false; 16 17 void __init kaslr_init(void) 18 { 19 if (kaslr_disabled_cmdline()) { 20 pr_info("KASLR disabled on command line\n"); 21 return; 22 } 23 24 /* 25 * The KASLR offset modulo MIN_KIMG_ALIGN is taken from the physical 26 * placement of the image rather than from the seed, so a displacement 27 * of less than MIN_KIMG_ALIGN means that no seed was provided. 28 */ 29 if (kaslr_offset() < MIN_KIMG_ALIGN) { 30 pr_warn("KASLR disabled due to lack of seed\n"); 31 return; 32 } 33 34 pr_info("KASLR enabled\n"); 35 __kaslr_is_enabled = true; 36 } 37 38 static int __init parse_nokaslr(char *unused) 39 { 40 /* nokaslr param handling is done by early cpufeature code */ 41 return 0; 42 } 43 early_param("nokaslr", parse_nokaslr); 44