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a35707c3d8
Some current cpus based on T-Head cores implement memory-types way different than described in the svpbmt spec even going so far as using PTE bits marked as reserved. Add the T-Head vendor-id and necessary errata code to replace the affected instructions. Signed-off-by: Heiko Stuebner <heiko@sntech.de> Tested-by: Samuel Holland <samuel@sholland.org> Link: https://lore.kernel.org/r/20220511192921.2223629-13-heiko@sntech.de Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
83 lines
2.1 KiB
C
83 lines
2.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2021 Heiko Stuebner <heiko@sntech.de>
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*/
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#include <linux/bug.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/string.h>
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#include <linux/uaccess.h>
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#include <asm/alternative.h>
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#include <asm/cacheflush.h>
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#include <asm/errata_list.h>
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#include <asm/patch.h>
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#include <asm/vendorid_list.h>
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struct errata_info {
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char name[ERRATA_STRING_LENGTH_MAX];
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bool (*check_func)(unsigned long arch_id, unsigned long impid);
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unsigned int stage;
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};
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static bool errata_mt_check_func(unsigned long arch_id, unsigned long impid)
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{
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if (arch_id != 0 || impid != 0)
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return false;
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return true;
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}
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static const struct errata_info errata_list[ERRATA_THEAD_NUMBER] = {
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{
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.name = "memory-types",
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.stage = RISCV_ALTERNATIVES_EARLY_BOOT,
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.check_func = errata_mt_check_func
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},
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};
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static u32 thead_errata_probe(unsigned int stage, unsigned long archid, unsigned long impid)
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{
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const struct errata_info *info;
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u32 cpu_req_errata = 0;
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int idx;
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for (idx = 0; idx < ERRATA_THEAD_NUMBER; idx++) {
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info = &errata_list[idx];
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if ((stage == RISCV_ALTERNATIVES_MODULE ||
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info->stage == stage) && info->check_func(archid, impid))
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cpu_req_errata |= (1U << idx);
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}
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return cpu_req_errata;
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}
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void __init_or_module thead_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
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unsigned long archid, unsigned long impid,
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unsigned int stage)
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{
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struct alt_entry *alt;
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u32 cpu_req_errata = thead_errata_probe(stage, archid, impid);
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u32 tmp;
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for (alt = begin; alt < end; alt++) {
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if (alt->vendor_id != THEAD_VENDOR_ID)
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continue;
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if (alt->errata_id >= ERRATA_THEAD_NUMBER)
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continue;
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tmp = (1U << alt->errata_id);
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if (cpu_req_errata & tmp) {
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/* On vm-alternatives, the mmu isn't running yet */
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if (stage == RISCV_ALTERNATIVES_EARLY_BOOT)
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memcpy((void *)__pa_symbol(alt->old_ptr),
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(void *)__pa_symbol(alt->alt_ptr), alt->alt_len);
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else
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patch_text_nosync(alt->old_ptr, alt->alt_ptr, alt->alt_len);
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}
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}
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if (stage == RISCV_ALTERNATIVES_EARLY_BOOT)
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local_flush_icache_all();
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}
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