| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * Copyright (C) 2016 Linaro Ltd <ard.biesheuvel@linaro.org> |
| */ |
| |
| #include <linux/cache.h> |
| #include <linux/init.h> |
| #include <linux/printk.h> |
| |
| #include <asm/cpufeature.h> |
| #include <asm/memory.h> |
| |
| u16 __initdata memstart_offset_seed; |
| |
| bool __ro_after_init __kaslr_is_enabled = false; |
| |
| void __init kaslr_init(void) |
| { |
| if (cpuid_feature_extract_unsigned_field(arm64_sw_feature_override.val & |
| arm64_sw_feature_override.mask, |
| ARM64_SW_FEATURE_OVERRIDE_NOKASLR)) { |
| pr_info("KASLR disabled on command line\n"); |
| return; |
| } |
| |
| /* |
| * The KASLR offset modulo MIN_KIMG_ALIGN is taken from the physical |
| * placement of the image rather than from the seed, so a displacement |
| * of less than MIN_KIMG_ALIGN means that no seed was provided. |
| */ |
| if (kaslr_offset() < MIN_KIMG_ALIGN) { |
| pr_warn("KASLR disabled due to lack of seed\n"); |
| return; |
| } |
| |
| pr_info("KASLR enabled\n"); |
| __kaslr_is_enabled = true; |
| } |
| |
| static int __init parse_nokaslr(char *unused) |
| { |
| /* nokaslr param handling is done by early cpufeature code */ |
| return 0; |
| } |
| early_param("nokaslr", parse_nokaslr); |