1 /* 2 * Contains CPU feature definitions 3 * 4 * Copyright (C) 2015 ARM Ltd. 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program. If not, see <http://www.gnu.org/licenses/>. 17 */ 18 19 #define pr_fmt(fmt) "alternatives: " fmt 20 21 #include <linux/types.h> 22 #include <asm/cpu.h> 23 #include <asm/cpufeature.h> 24 25 static bool 26 has_id_aa64pfr0_feature(const struct arm64_cpu_capabilities *entry) 27 { 28 u64 val; 29 30 val = read_cpuid(id_aa64pfr0_el1); 31 return (val & entry->register_mask) == entry->register_value; 32 } 33 34 static const struct arm64_cpu_capabilities arm64_features[] = { 35 { 36 .desc = "GIC system register CPU interface", 37 .capability = ARM64_HAS_SYSREG_GIC_CPUIF, 38 .matches = has_id_aa64pfr0_feature, 39 .register_mask = (0xf << 24), 40 .register_value = (1 << 24), 41 }, 42 {}, 43 }; 44 45 void check_cpu_capabilities(const struct arm64_cpu_capabilities *caps, 46 const char *info) 47 { 48 int i; 49 50 for (i = 0; caps[i].desc; i++) { 51 if (!caps[i].matches(&caps[i])) 52 continue; 53 54 if (!cpus_have_cap(caps[i].capability)) 55 pr_info("%s %s\n", info, caps[i].desc); 56 cpus_set_cap(caps[i].capability); 57 } 58 } 59 60 void check_local_cpu_features(void) 61 { 62 check_cpu_capabilities(arm64_features, "detected feature"); 63 } 64