arch/riscv/errata/thead/errata.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2021 Heiko Stuebner <heiko@sntech.de>
   4  */
   5
   6 #include <linux/bug.h>
   7 #include <linux/kernel.h>
   8 #include <linux/memory.h>
   9 #include <linux/module.h>
  10 #include <linux/string.h>
  11 #include <linux/uaccess.h>
  12 #include <asm/alternative.h>
  13 #include <asm/cacheflush.h>
  14 #include <asm/cpufeature.h>
  15 #include <asm/errata_list.h>
  16 #include <asm/hwprobe.h>
  17 #include <asm/patch.h>
  18 #include <asm/vendorid_list.h>
  19
  20 static bool errata_probe_pbmt(unsigned int stage,
  21                               unsigned long arch_id, unsigned long impid)
  22 {
  23         if (!IS_ENABLED(CONFIG_ERRATA_THEAD_PBMT))
  24                 return false;
  25
  26         if (arch_id != 0 || impid != 0)
  27                 return false;
  28
  29         if (stage == RISCV_ALTERNATIVES_EARLY_BOOT ||
  30             stage == RISCV_ALTERNATIVES_MODULE)
  31                 return true;
  32
  33         return false;
  34 }
  35
  36 static bool errata_probe_cmo(unsigned int stage,
  37                              unsigned long arch_id, unsigned long impid)
  38 {
  39         if (!IS_ENABLED(CONFIG_ERRATA_THEAD_CMO))
  40                 return false;
  41
  42         if (arch_id != 0 || impid != 0)
  43                 return false;
  44
  45         if (stage == RISCV_ALTERNATIVES_EARLY_BOOT)
  46                 return false;
  47
  48         if (stage == RISCV_ALTERNATIVES_BOOT) {
  49                 riscv_cbom_block_size = L1_CACHE_BYTES;
  50                 riscv_noncoherent_supported();
  51         }
  52
  53         return true;
  54 }
  55
  56 static bool errata_probe_pmu(unsigned int stage,
  57                              unsigned long arch_id, unsigned long impid)
  58 {
  59         if (!IS_ENABLED(CONFIG_ERRATA_THEAD_PMU))
  60                 return false;
  61
  62         /* target-c9xx cores report arch_id and impid as 0 */
  63         if (arch_id != 0 || impid != 0)
  64                 return false;
  65
  66         if (stage == RISCV_ALTERNATIVES_EARLY_BOOT)
  67                 return false;
  68
  69         return true;
  70 }
  71
  72 static u32 thead_errata_probe(unsigned int stage,
  73                               unsigned long archid, unsigned long impid)
  74 {
  75         u32 cpu_req_errata = 0;
  76
  77         if (errata_probe_pbmt(stage, archid, impid))
  78                 cpu_req_errata |= BIT(ERRATA_THEAD_PBMT);
  79
  80         if (errata_probe_cmo(stage, archid, impid))
  81                 cpu_req_errata |= BIT(ERRATA_THEAD_CMO);
  82
  83         if (errata_probe_pmu(stage, archid, impid))
  84                 cpu_req_errata |= BIT(ERRATA_THEAD_PMU);
  85
  86         return cpu_req_errata;
  87 }
  88
  89 void thead_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
  90                              unsigned long archid, unsigned long impid,
  91                              unsigned int stage)
  92 {
  93         struct alt_entry *alt;
  94         u32 cpu_req_errata = thead_errata_probe(stage, archid, impid);
  95         u32 tmp;
  96         void *oldptr, *altptr;
  97
  98         for (alt = begin; alt < end; alt++) {
  99                 if (alt->vendor_id != THEAD_VENDOR_ID)
 100                         continue;
 101                 if (alt->patch_id >= ERRATA_THEAD_NUMBER)
 102                         continue;
 103
 104                 tmp = (1U << alt->patch_id);
 105                 if (cpu_req_errata & tmp) {
 106                         oldptr = ALT_OLD_PTR(alt);
 107                         altptr = ALT_ALT_PTR(alt);
 108
 109                         /* On vm-alternatives, the mmu isn't running yet */
 110                         if (stage == RISCV_ALTERNATIVES_EARLY_BOOT) {
 111                                 memcpy(oldptr, altptr, alt->alt_len);
 112                         } else {
 113                                 mutex_lock(&text_mutex);
 114                                 patch_text_nosync(oldptr, altptr, alt->alt_len);
 115                                 mutex_unlock(&text_mutex);
 116                         }
 117                 }
 118         }
 119
 120         if (stage == RISCV_ALTERNATIVES_EARLY_BOOT)
 121                 local_flush_icache_all();
 122 }