arch/arm64/kernel/cpu_errata.c

   1 /*
   2  * Contains CPU specific errata definitions
   3  *
   4  * Copyright (C) 2014 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) "alternative: " fmt
  20
  21 #include <linux/types.h>
  22 #include <asm/cpu.h>
  23 #include <asm/cputype.h>
  24 #include <asm/cpufeature.h>
  25
  26 #define MIDR_CORTEX_A53 MIDR_CPU_PART(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A53)
  27 #define MIDR_CORTEX_A57 MIDR_CPU_PART(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A57)
  28
  29 /*
  30  * Add a struct or another datatype to the union below if you need
  31  * different means to detect an affected CPU.
  32  */
  33 struct arm64_cpu_capabilities {
  34         const char *desc;
  35         u16 capability;
  36         bool (*is_affected)(struct arm64_cpu_capabilities *);
  37         union {
  38                 struct {
  39                         u32 midr_model;
  40                         u32 midr_range_min, midr_range_max;
  41                 };
  42         };
  43 };
  44
  45 #define CPU_MODEL_MASK (MIDR_IMPLEMENTOR_MASK | MIDR_PARTNUM_MASK | \
  46                         MIDR_ARCHITECTURE_MASK)
  47
  48 static bool __maybe_unused
  49 is_affected_midr_range(struct arm64_cpu_capabilities *entry)
  50 {
  51         u32 midr = read_cpuid_id();
  52
  53         if ((midr & CPU_MODEL_MASK) != entry->midr_model)
  54                 return false;
  55
  56         midr &= MIDR_REVISION_MASK | MIDR_VARIANT_MASK;
  57
  58         return (midr >= entry->midr_range_min && midr <= entry->midr_range_max);
  59 }
  60
  61 #define MIDR_RANGE(model, min, max) \
  62         .is_affected = is_affected_midr_range, \
  63         .midr_model = model, \
  64         .midr_range_min = min, \
  65         .midr_range_max = max
  66
  67 struct arm64_cpu_capabilities arm64_errata[] = {
  68         {
  69         /* Cortex-A53 r0p[012] */
  70                 .desc = "ARM errata 826319, 827319, 824069",
  71                 .capability = ARM64_WORKAROUND_CLEAN_CACHE,
  72                 MIDR_RANGE(MIDR_CORTEX_A53, 0x00, 0x02),
  73         },
  74         {
  75         /* Cortex-A57 r0p0 - r1p2 */
  76                 .desc = "ARM erratum 832075",
  77                 .capability = ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE,
  78                 MIDR_RANGE(MIDR_CORTEX_A57, 0x00, 0x12),
  79         },
  80         {
  81         }
  82 };
  83
  84 void check_local_cpu_errata(void)
  85 {
  86         struct arm64_cpu_capabilities *cpus = arm64_errata;
  87         int i;
  88
  89         for (i = 0; cpus[i].desc; i++) {
  90                 if (!cpus[i].is_affected(&cpus[i]))
  91                         continue;
  92
  93                 if (!cpus_have_cap(cpus[i].capability))
  94                         pr_info("enabling workaround for %s\n", cpus[i].desc);
  95                 cpus_set_cap(cpus[i].capability);
  96         }
  97 }