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 static bool errata_probe_pbmt(unsigned int stage,
  18                               unsigned long arch_id, unsigned long impid)
  19 {
  20         if (!IS_ENABLED(CONFIG_ERRATA_THEAD_PBMT))
  21                 return false;
  22
  23         if (arch_id != 0 || impid != 0)
  24                 return false;
  25
  26         if (stage == RISCV_ALTERNATIVES_EARLY_BOOT ||
  27             stage == RISCV_ALTERNATIVES_MODULE)
  28                 return true;
  29
  30         return false;
  31 }
  32
  33 static bool errata_probe_cmo(unsigned int stage,
  34                              unsigned long arch_id, unsigned long impid)
  35 {
  36         if (!IS_ENABLED(CONFIG_ERRATA_THEAD_CMO))
  37                 return false;
  38
  39         if (arch_id != 0 || impid != 0)
  40                 return false;
  41
  42         if (stage == RISCV_ALTERNATIVES_EARLY_BOOT)
  43                 return false;
  44
  45         riscv_cbom_block_size = L1_CACHE_BYTES;
  46         riscv_noncoherent_supported();
  47         return true;
  48 }
  49
  50 static u32 thead_errata_probe(unsigned int stage,
  51                               unsigned long archid, unsigned long impid)
  52 {
  53         u32 cpu_req_errata = 0;
  54
  55         if (errata_probe_pbmt(stage, archid, impid))
  56                 cpu_req_errata |= BIT(ERRATA_THEAD_PBMT);
  57
  58         if (errata_probe_cmo(stage, archid, impid))
  59                 cpu_req_errata |= BIT(ERRATA_THEAD_CMO);
  60
  61         return cpu_req_errata;
  62 }
  63
  64 void __init_or_module thead_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
  65                                               unsigned long archid, unsigned long impid,
  66                                               unsigned int stage)
  67 {
  68         struct alt_entry *alt;
  69         u32 cpu_req_errata = thead_errata_probe(stage, archid, impid);
  70         u32 tmp;
  71
  72         for (alt = begin; alt < end; alt++) {
  73                 if (alt->vendor_id != THEAD_VENDOR_ID)
  74                         continue;
  75                 if (alt->errata_id >= ERRATA_THEAD_NUMBER)
  76                         continue;
  77
  78                 tmp = (1U << alt->errata_id);
  79                 if (cpu_req_errata & tmp) {
  80                         /* On vm-alternatives, the mmu isn't running yet */
  81                         if (stage == RISCV_ALTERNATIVES_EARLY_BOOT)
  82                                 memcpy((void *)__pa_symbol(alt->old_ptr),
  83                                        (void *)__pa_symbol(alt->alt_ptr), alt->alt_len);
  84                         else
  85                                 patch_text_nosync(alt->old_ptr, alt->alt_ptr, alt->alt_len);
  86                 }
  87         }
  88
  89         if (stage == RISCV_ALTERNATIVES_EARLY_BOOT)
  90                 local_flush_icache_all();
  91 }