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// 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>
static struct cpu_manufacturer_info_t {
unsigned long vendor_id;
unsigned long arch_id;
unsigned long imp_id;
} cpu_mfr_info;
static void (*vendor_patch_func)(struct alt_entry *begin, struct alt_entry *end,
unsigned long archid, unsigned long impid,
unsigned int stage) __initdata_or_module;
static inline void __init riscv_fill_cpu_mfr_info(void)
{
#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
}
static void __init init_alternative(void)
{
riscv_fill_cpu_mfr_info();
switch (cpu_mfr_info.vendor_id) {
#ifdef CONFIG_ERRATA_SIFIVE
case SIFIVE_VENDOR_ID:
vendor_patch_func = sifive_errata_patch_func;
break;
#endif
default:
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)
{
if (!vendor_patch_func)
return;
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);
init_alternative();
_apply_alternatives((struct alt_entry *)__alt_start,
(struct alt_entry *)__alt_end,
RISCV_ALTERNATIVES_BOOT);
}
#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
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