// SPDX-License-Identifier: GPL-2.0-only/* Copyright (C) 2020 SiFive * Copyright (C) 2025 Chen Miao */ #include <linux/mm.h>#include <linux/kernel.h>#include <linux/spinlock.h>#include <linux/uaccess.h> #include <asm/insn-def.h>#include <asm/cacheflush.h>#include <asm/page.h>#include <asm/fixmap.h>#include <asm/text-patching.h>#include <asm/sections.h> static DEFINE_RAW_SPINLOCK(patch_lock); static __always_inline void *patch_map(void *addr, int fixmap){	uintptr_t uaddr = (uintptr_t) addr;	phys_addr_t phys; 	if (core_kernel_text(uaddr)) {		phys = __pa_symbol(addr);	} else {		struct page *page = vmalloc_to_page(addr);		BUG_ON(!page);		phys = page_to_phys(page) + offset_in_page(addr);	} 	return (void *)set_fixmap_offset(fixmap, phys);} static void patch_unmap(int fixmap){	clear_fixmap(fixmap);} static int __patch_insn_write(void *addr, u32 insn){	void *waddr = addr;	unsigned long flags = 0;	int ret; 	raw_spin_lock_irqsave(&patch_lock, flags); 	waddr = patch_map(addr, FIX_TEXT_POKE0); 	ret = copy_to_kernel_nofault(waddr, &insn, OPENRISC_INSN_SIZE);	if (!IS_ENABLED(CONFIG_DCACHE_WRITETHROUGH))		local_dcache_range_flush((unsigned long)waddr,					 (unsigned long)waddr + OPENRISC_INSN_SIZE);	local_icache_range_inv((unsigned long)waddr,			       (unsigned long)waddr + OPENRISC_INSN_SIZE); 	patch_unmap(FIX_TEXT_POKE0); 	raw_spin_unlock_irqrestore(&patch_lock, flags); 	return ret;} /* * patch_insn_write - Write a single instruction to a specified memory location * This API provides a single-instruction patching, primarily used for runtime * code modification. * By the way, the insn size must be 4 bytes. */int patch_insn_write(void *addr, u32 insn){	u32 *tp = addr;	int ret; 	if ((uintptr_t) tp & 0x3)		return -EINVAL; 	ret = __patch_insn_write(tp, insn); 	return ret;}