1 /* 2 * Record and handle CPU attributes. 3 * 4 * Copyright (C) 2014 ARM Ltd. 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License version 2 as 7 * published by the Free Software Foundation. 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * GNU General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program. If not, see <http://www.gnu.org/licenses/>. 16 */ 17 #include <asm/arch_timer.h> 18 #include <asm/cachetype.h> 19 #include <asm/cpu.h> 20 #include <asm/cputype.h> 21 #include <asm/cpufeature.h> 22 23 #include <linux/bitops.h> 24 #include <linux/bug.h> 25 #include <linux/init.h> 26 #include <linux/kernel.h> 27 #include <linux/preempt.h> 28 #include <linux/printk.h> 29 #include <linux/smp.h> 30 31 /* 32 * In case the boot CPU is hotpluggable, we record its initial state and 33 * current state separately. Certain system registers may contain different 34 * values depending on configuration at or after reset. 35 */ 36 DEFINE_PER_CPU(struct cpuinfo_arm64, cpu_data); 37 static struct cpuinfo_arm64 boot_cpu_data; 38 39 static char *icache_policy_str[] = { 40 [ICACHE_POLICY_RESERVED] = "RESERVED/UNKNOWN", 41 [ICACHE_POLICY_AIVIVT] = "AIVIVT", 42 [ICACHE_POLICY_VIPT] = "VIPT", 43 [ICACHE_POLICY_PIPT] = "PIPT", 44 }; 45 46 unsigned long __icache_flags; 47 48 static void cpuinfo_detect_icache_policy(struct cpuinfo_arm64 *info) 49 { 50 unsigned int cpu = smp_processor_id(); 51 u32 l1ip = CTR_L1IP(info->reg_ctr); 52 53 if (l1ip != ICACHE_POLICY_PIPT) { 54 /* 55 * VIPT caches are non-aliasing if the VA always equals the PA 56 * in all bit positions that are covered by the index. This is 57 * the case if the size of a way (# of sets * line size) does 58 * not exceed PAGE_SIZE. 59 */ 60 u32 waysize = icache_get_numsets() * icache_get_linesize(); 61 62 if (l1ip != ICACHE_POLICY_VIPT || waysize > PAGE_SIZE) 63 set_bit(ICACHEF_ALIASING, &__icache_flags); 64 } 65 if (l1ip == ICACHE_POLICY_AIVIVT) 66 set_bit(ICACHEF_AIVIVT, &__icache_flags); 67 68 pr_info("Detected %s I-cache on CPU%d\n", icache_policy_str[l1ip], cpu); 69 } 70 71 static int check_reg_mask(char *name, u64 mask, u64 boot, u64 cur, int cpu) 72 { 73 if ((boot & mask) == (cur & mask)) 74 return 0; 75 76 pr_warn("SANITY CHECK: Unexpected variation in %s. Boot CPU: %#016lx, CPU%d: %#016lx\n", 77 name, (unsigned long)boot, cpu, (unsigned long)cur); 78 79 return 1; 80 } 81 82 #define CHECK_MASK(field, mask, boot, cur, cpu) \ 83 check_reg_mask(#field, mask, (boot)->reg_ ## field, (cur)->reg_ ## field, cpu) 84 85 #define CHECK(field, boot, cur, cpu) \ 86 CHECK_MASK(field, ~0ULL, boot, cur, cpu) 87 88 /* 89 * Verify that CPUs don't have unexpected differences that will cause problems. 90 */ 91 static void cpuinfo_sanity_check(struct cpuinfo_arm64 *cur) 92 { 93 unsigned int cpu = smp_processor_id(); 94 struct cpuinfo_arm64 *boot = &boot_cpu_data; 95 unsigned int diff = 0; 96 97 /* 98 * The kernel can handle differing I-cache policies, but otherwise 99 * caches should look identical. Userspace JITs will make use of 100 * *minLine. 101 */ 102 diff |= CHECK_MASK(ctr, 0xffff3fff, boot, cur, cpu); 103 104 /* 105 * Userspace may perform DC ZVA instructions. Mismatched block sizes 106 * could result in too much or too little memory being zeroed if a 107 * process is preempted and migrated between CPUs. 108 */ 109 diff |= CHECK(dczid, boot, cur, cpu); 110 111 /* If different, timekeeping will be broken (especially with KVM) */ 112 diff |= CHECK(cntfrq, boot, cur, cpu); 113 114 /* 115 * Even in big.LITTLE, processors should be identical instruction-set 116 * wise. 117 */ 118 diff |= CHECK(id_aa64isar0, boot, cur, cpu); 119 diff |= CHECK(id_aa64isar1, boot, cur, cpu); 120 121 /* 122 * Differing PARange support is fine as long as all peripherals and 123 * memory are mapped within the minimum PARange of all CPUs. 124 * Linux should not care about secure memory. 125 * ID_AA64MMFR1 is currently RES0. 126 */ 127 diff |= CHECK_MASK(id_aa64mmfr0, 0xffffffffffff0ff0, boot, cur, cpu); 128 diff |= CHECK(id_aa64mmfr1, boot, cur, cpu); 129 130 /* 131 * EL3 is not our concern. 132 * ID_AA64PFR1 is currently RES0. 133 */ 134 diff |= CHECK_MASK(id_aa64pfr0, 0xffffffffffff0fff, boot, cur, cpu); 135 diff |= CHECK(id_aa64pfr1, boot, cur, cpu); 136 137 /* 138 * If we have AArch32, we care about 32-bit features for compat. These 139 * registers should be RES0 otherwise. 140 */ 141 diff |= CHECK(id_isar0, boot, cur, cpu); 142 diff |= CHECK(id_isar1, boot, cur, cpu); 143 diff |= CHECK(id_isar2, boot, cur, cpu); 144 diff |= CHECK(id_isar3, boot, cur, cpu); 145 diff |= CHECK(id_isar4, boot, cur, cpu); 146 diff |= CHECK(id_isar5, boot, cur, cpu); 147 /* 148 * Regardless of the value of the AuxReg field, the AIFSR, ADFSR, and 149 * ACTLR formats could differ across CPUs and therefore would have to 150 * be trapped for virtualization anyway. 151 */ 152 diff |= CHECK_MASK(id_mmfr0, 0xff0fffff, boot, cur, cpu); 153 diff |= CHECK(id_mmfr1, boot, cur, cpu); 154 diff |= CHECK(id_mmfr2, boot, cur, cpu); 155 diff |= CHECK(id_mmfr3, boot, cur, cpu); 156 diff |= CHECK(id_pfr0, boot, cur, cpu); 157 diff |= CHECK(id_pfr1, boot, cur, cpu); 158 159 /* 160 * Mismatched CPU features are a recipe for disaster. Don't even 161 * pretend to support them. 162 */ 163 WARN_TAINT_ONCE(diff, TAINT_CPU_OUT_OF_SPEC, 164 "Unsupported CPU feature variation.\n"); 165 } 166 167 static void __cpuinfo_store_cpu(struct cpuinfo_arm64 *info) 168 { 169 info->reg_cntfrq = arch_timer_get_cntfrq(); 170 info->reg_ctr = read_cpuid_cachetype(); 171 info->reg_dczid = read_cpuid(DCZID_EL0); 172 info->reg_midr = read_cpuid_id(); 173 174 info->reg_id_aa64isar0 = read_cpuid(ID_AA64ISAR0_EL1); 175 info->reg_id_aa64isar1 = read_cpuid(ID_AA64ISAR1_EL1); 176 info->reg_id_aa64mmfr0 = read_cpuid(ID_AA64MMFR0_EL1); 177 info->reg_id_aa64mmfr1 = read_cpuid(ID_AA64MMFR1_EL1); 178 info->reg_id_aa64pfr0 = read_cpuid(ID_AA64PFR0_EL1); 179 info->reg_id_aa64pfr1 = read_cpuid(ID_AA64PFR1_EL1); 180 181 info->reg_id_isar0 = read_cpuid(ID_ISAR0_EL1); 182 info->reg_id_isar1 = read_cpuid(ID_ISAR1_EL1); 183 info->reg_id_isar2 = read_cpuid(ID_ISAR2_EL1); 184 info->reg_id_isar3 = read_cpuid(ID_ISAR3_EL1); 185 info->reg_id_isar4 = read_cpuid(ID_ISAR4_EL1); 186 info->reg_id_isar5 = read_cpuid(ID_ISAR5_EL1); 187 info->reg_id_mmfr0 = read_cpuid(ID_MMFR0_EL1); 188 info->reg_id_mmfr1 = read_cpuid(ID_MMFR1_EL1); 189 info->reg_id_mmfr2 = read_cpuid(ID_MMFR2_EL1); 190 info->reg_id_mmfr3 = read_cpuid(ID_MMFR3_EL1); 191 info->reg_id_pfr0 = read_cpuid(ID_PFR0_EL1); 192 info->reg_id_pfr1 = read_cpuid(ID_PFR1_EL1); 193 194 cpuinfo_detect_icache_policy(info); 195 196 check_local_cpu_errata(); 197 } 198 199 void cpuinfo_store_cpu(void) 200 { 201 struct cpuinfo_arm64 *info = this_cpu_ptr(&cpu_data); 202 __cpuinfo_store_cpu(info); 203 cpuinfo_sanity_check(info); 204 } 205 206 void __init cpuinfo_store_boot_cpu(void) 207 { 208 struct cpuinfo_arm64 *info = &per_cpu(cpu_data, 0); 209 __cpuinfo_store_cpu(info); 210 211 boot_cpu_data = *info; 212 } 213 214 u64 __attribute_const__ icache_get_ccsidr(void) 215 { 216 u64 ccsidr; 217 218 WARN_ON(preemptible()); 219 220 /* Select L1 I-cache and read its size ID register */ 221 asm("msr csselr_el1, %1; isb; mrs %0, ccsidr_el1" 222 : "=r"(ccsidr) : "r"(1L)); 223 return ccsidr; 224 } 225