1d2912cb1SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 2f80fb3a3SArd Biesheuvel /* 3f80fb3a3SArd Biesheuvel * Copyright (C) 2016 Linaro Ltd <ard.biesheuvel@linaro.org> 4f80fb3a3SArd Biesheuvel */ 5f80fb3a3SArd Biesheuvel 65a9e3e15SJisheng Zhang #include <linux/cache.h> 7f80fb3a3SArd Biesheuvel #include <linux/init.h> 8f80fb3a3SArd Biesheuvel #include <linux/printk.h> 9f80fb3a3SArd Biesheuvel 10f80fb3a3SArd Biesheuvel #include <asm/cpufeature.h> 11f80fb3a3SArd Biesheuvel #include <asm/memory.h> 12f80fb3a3SArd Biesheuvel 1365fddcfcSMike Rapoport u16 __initdata memstart_offset_seed; 1458552408SLinus Torvalds 15f80fb3a3SArd Biesheuvel bool __ro_after_init __kaslr_is_enabled = false; 16f80fb3a3SArd Biesheuvel kaslr_init(void)17f80fb3a3SArd Biesheuvelvoid __init kaslr_init(void) 18f80fb3a3SArd Biesheuvel { 19f80fb3a3SArd Biesheuvel if (cpuid_feature_extract_unsigned_field(arm64_sw_feature_override.val & 20f80fb3a3SArd Biesheuvel arm64_sw_feature_override.mask, 21f6f0c436SMarc Zyngier ARM64_SW_FEATURE_OVERRIDE_NOKASLR)) { 22f80fb3a3SArd Biesheuvel pr_info("KASLR disabled on command line\n"); 235a9e3e15SJisheng Zhang return; 24c031a421SArd Biesheuvel } 25f80fb3a3SArd Biesheuvel 26fc5a89f7SArd Biesheuvel /* 27fc5a89f7SArd Biesheuvel * The KASLR offset modulo MIN_KIMG_ALIGN is taken from the physical 28fc5a89f7SArd Biesheuvel * placement of the image rather than from the seed, so a displacement 29fc5a89f7SArd Biesheuvel * of less than MIN_KIMG_ALIGN means that no seed was provided. 30fc5a89f7SArd Biesheuvel */ 31f80fb3a3SArd Biesheuvel if (kaslr_offset() < MIN_KIMG_ALIGN) { 32fc5a89f7SArd Biesheuvel pr_warn("KASLR disabled due to lack of seed\n"); 33fc5a89f7SArd Biesheuvel return; 34f80fb3a3SArd Biesheuvel } 35fc5a89f7SArd Biesheuvel 36fc5a89f7SArd Biesheuvel pr_info("KASLR enabled\n"); 37*0ddc312bSMarc Zyngier __kaslr_is_enabled = true; 38*0ddc312bSMarc Zyngier } 39*0ddc312bSMarc Zyngier