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// 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);
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;
}
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