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/module.h>
   9 #include <linux/string.h>
  10 #include <linux/uaccess.h>
  11 #include <asm/alternative.h>
  12 #include <asm/cacheflush.h>
  13 #include <asm/errata_list.h>
  14 #include <asm/patch.h>
  15 #include <asm/vendorid_list.h>
  16
  17 struct errata_info {
  18         char name[ERRATA_STRING_LENGTH_MAX];
  19         bool (*check_func)(unsigned long arch_id, unsigned long impid);
  20         unsigned int stage;
  21 };
  22
  23 static bool errata_mt_check_func(unsigned long  arch_id, unsigned long impid)
  24 {
  25         if (arch_id != 0 || impid != 0)
  26                 return false;
  27         return true;
  28 }
  29
  30 static const struct errata_info errata_list[ERRATA_THEAD_NUMBER] = {
  31         {
  32                 .name = "memory-types",
  33                 .stage = RISCV_ALTERNATIVES_EARLY_BOOT,
  34                 .check_func = errata_mt_check_func
  35         },
  36 };
  37
  38 static u32 thead_errata_probe(unsigned int stage, unsigned long archid, unsigned long impid)
  39 {
  40         const struct errata_info *info;
  41         u32 cpu_req_errata = 0;
  42         int idx;
  43
  44         for (idx = 0; idx < ERRATA_THEAD_NUMBER; idx++) {
  45                 info = &errata_list[idx];
  46
  47                 if ((stage == RISCV_ALTERNATIVES_MODULE ||
  48                      info->stage == stage) && info->check_func(archid, impid))
  49                         cpu_req_errata |= (1U << idx);
  50         }
  51
  52         return cpu_req_errata;
  53 }
  54
  55 void __init_or_module thead_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
  56                                               unsigned long archid, unsigned long impid,
  57                                               unsigned int stage)
  58 {
  59         struct alt_entry *alt;
  60         u32 cpu_req_errata = thead_errata_probe(stage, archid, impid);
  61         u32 tmp;
  62
  63         for (alt = begin; alt < end; alt++) {
  64                 if (alt->vendor_id != THEAD_VENDOR_ID)
  65                         continue;
  66                 if (alt->errata_id >= ERRATA_THEAD_NUMBER)
  67                         continue;
  68
  69                 tmp = (1U << alt->errata_id);
  70                 if (cpu_req_errata & tmp) {
  71                         /* On vm-alternatives, the mmu isn't running yet */
  72                         if (stage == RISCV_ALTERNATIVES_EARLY_BOOT)
  73                                 memcpy((void *)__pa_symbol(alt->old_ptr),
  74                                        (void *)__pa_symbol(alt->alt_ptr), alt->alt_len);
  75                         else
  76                                 patch_text_nosync(alt->old_ptr, alt->alt_ptr, alt->alt_len);
  77                 }
  78         }
  79
  80         if (stage == RISCV_ALTERNATIVES_EARLY_BOOT)
  81                 local_flush_icache_all();
  82 }