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