1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * KFENCE support for LoongArch.
4 *
5 * Author: Enze Li <lienze@kylinos.cn>
6 * Copyright (C) 2022-2023 KylinSoft Corporation.
7 */
8
9#ifndef _ASM_LOONGARCH_KFENCE_H
10#define _ASM_LOONGARCH_KFENCE_H
11
12#include <linux/kfence.h>
13#include <asm/pgtable.h>
14#include <asm/tlb.h>
15
16static inline bool arch_kfence_init_pool(void)
17{
18	int err;
19	char *kaddr, *vaddr;
20	char *kfence_pool = __kfence_pool;
21	struct vm_struct *area;
22
23	area = __get_vm_area_caller(KFENCE_POOL_SIZE, VM_IOREMAP,
24				    KFENCE_AREA_START, KFENCE_AREA_END,
25				    __builtin_return_address(0));
26	if (!area)
27		return false;
28
29	__kfence_pool = (char *)area->addr;
30	err = ioremap_page_range((unsigned long)__kfence_pool,
31				 (unsigned long)__kfence_pool + KFENCE_POOL_SIZE,
32				 virt_to_phys((void *)kfence_pool), PAGE_KERNEL);
33	if (err) {
34		free_vm_area(area);
35		__kfence_pool = kfence_pool;
36		return false;
37	}
38
39	kaddr = kfence_pool;
40	vaddr = __kfence_pool;
41	while (kaddr < kfence_pool + KFENCE_POOL_SIZE) {
42		set_page_address(virt_to_page(kaddr), vaddr);
43		kaddr += PAGE_SIZE;
44		vaddr += PAGE_SIZE;
45	}
46
47	return true;
48}
49
50/* Protect the given page and flush TLB. */
51static inline bool kfence_protect_page(unsigned long addr, bool protect)
52{
53	pte_t *pte = virt_to_kpte(addr);
54
55	if (WARN_ON(!pte) || pte_none(*pte))
56		return false;
57
58	if (protect)
59		set_pte(pte, __pte(pte_val(*pte) & ~(_PAGE_VALID | _PAGE_PRESENT)));
60	else
61		set_pte(pte, __pte(pte_val(*pte) | (_PAGE_VALID | _PAGE_PRESENT)));
62
63	preempt_disable();
64	local_flush_tlb_one(addr);
65	preempt_enable();
66
67	return true;
68}
69
70#endif /* _ASM_LOONGARCH_KFENCE_H */
71