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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 | // SPDX-License-Identifier: GPL-2.0-only /* * alternative runtime patching * inspired by the ARM64 and x86 version * * Copyright (C) 2021 Sifive. */ #include <linux/init.h> #include <linux/module.h> #include <linux/cpu.h> #include <linux/uaccess.h> #include <asm/alternative.h> #include <asm/sections.h> #include <asm/vendorid_list.h> #include <asm/sbi.h> #include <asm/csr.h> struct cpu_manufacturer_info_t { unsigned long vendor_id; unsigned long arch_id; unsigned long imp_id; void (*vendor_patch_func)(struct alt_entry *begin, struct alt_entry *end, unsigned long archid, unsigned long impid, unsigned int stage); }; static void __init_or_module riscv_fill_cpu_mfr_info(struct cpu_manufacturer_info_t *cpu_mfr_info) { #ifdef CONFIG_RISCV_M_MODE cpu_mfr_info->vendor_id = csr_read(CSR_MVENDORID); cpu_mfr_info->arch_id = csr_read(CSR_MARCHID); cpu_mfr_info->imp_id = csr_read(CSR_MIMPID); #else cpu_mfr_info->vendor_id = sbi_get_mvendorid(); cpu_mfr_info->arch_id = sbi_get_marchid(); cpu_mfr_info->imp_id = sbi_get_mimpid(); #endif switch (cpu_mfr_info->vendor_id) { #ifdef CONFIG_ERRATA_SIFIVE case SIFIVE_VENDOR_ID: cpu_mfr_info->vendor_patch_func = sifive_errata_patch_func; break; #endif #ifdef CONFIG_ERRATA_THEAD case THEAD_VENDOR_ID: cpu_mfr_info->vendor_patch_func = thead_errata_patch_func; break; #endif default: cpu_mfr_info->vendor_patch_func = NULL; } } /* * This is called very early in the boot process (directly after we run * a feature detect on the boot CPU). No need to worry about other CPUs * here. */ static void __init_or_module _apply_alternatives(struct alt_entry *begin, struct alt_entry *end, unsigned int stage) { struct cpu_manufacturer_info_t cpu_mfr_info; riscv_fill_cpu_mfr_info(&cpu_mfr_info); riscv_cpufeature_patch_func(begin, end, stage); if (!cpu_mfr_info.vendor_patch_func) return; cpu_mfr_info.vendor_patch_func(begin, end, cpu_mfr_info.arch_id, cpu_mfr_info.imp_id, stage); } void __init apply_boot_alternatives(void) { /* If called on non-boot cpu things could go wrong */ WARN_ON(smp_processor_id() != 0); _apply_alternatives((struct alt_entry *)__alt_start, (struct alt_entry *)__alt_end, RISCV_ALTERNATIVES_BOOT); } /* * apply_early_boot_alternatives() is called from setup_vm() with MMU-off. * * Following requirements should be honoured for it to work correctly: * 1) It should use PC-relative addressing for accessing kernel symbols. * To achieve this we always use GCC cmodel=medany. * 2) The compiler instrumentation for FTRACE will not work for setup_vm() * so disable compiler instrumentation when FTRACE is enabled. * * Currently, the above requirements are honoured by using custom CFLAGS * for alternative.o in kernel/Makefile. */ void __init apply_early_boot_alternatives(void) { #ifdef CONFIG_RISCV_ALTERNATIVE_EARLY _apply_alternatives((struct alt_entry *)__alt_start, (struct alt_entry *)__alt_end, RISCV_ALTERNATIVES_EARLY_BOOT); #endif } #ifdef CONFIG_MODULES void apply_module_alternatives(void *start, size_t length) { _apply_alternatives((struct alt_entry *)start, (struct alt_entry *)(start + length), RISCV_ALTERNATIVES_MODULE); } #endif |