kfence.h

 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 <linux/vmalloc.h>
14#include <asm/pgtable.h>
15#include <asm/tlb.h>
16
17static inline bool arch_kfence_init_pool(void)
18{
19	int err;
20	char *kaddr, *vaddr;
21	char *kfence_pool = __kfence_pool;
22	struct vm_struct *area;
23
24	area = __get_vm_area_caller(KFENCE_POOL_SIZE, VM_IOREMAP,
25				    KFENCE_AREA_START, KFENCE_AREA_END,
26				    __builtin_return_address(0));
27	if (!area)
28		return false;
29
30	__kfence_pool = (char *)area->addr;
31	err = ioremap_page_range((unsigned long)__kfence_pool,
32				 (unsigned long)__kfence_pool + KFENCE_POOL_SIZE,
33				 virt_to_phys((void *)kfence_pool), PAGE_KERNEL);
34	if (err) {
35		free_vm_area(area);
36		__kfence_pool = kfence_pool;
37		return false;
38	}
39
40	kaddr = kfence_pool;
41	vaddr = __kfence_pool;
42	while (kaddr < kfence_pool + KFENCE_POOL_SIZE) {
43		set_page_address(virt_to_page(kaddr), vaddr);
44		kaddr += PAGE_SIZE;
45		vaddr += PAGE_SIZE;
46	}
47
48	return true;
49}
50
51/* Protect the given page and flush TLB. */
52static inline bool kfence_protect_page(unsigned long addr, bool protect)
53{
54	pte_t *pte = virt_to_kpte(addr);
55
56	if (WARN_ON(!pte) || pte_none(ptep_get(pte)))
57		return false;
58
59	if (protect)
60		set_pte(pte, __pte(pte_val(ptep_get(pte)) & ~(_PAGE_VALID | _PAGE_PRESENT)));
61	else
62		set_pte(pte, __pte(pte_val(ptep_get(pte)) | (_PAGE_VALID | _PAGE_PRESENT)));
63
64	preempt_disable();
65	local_flush_tlb_one(addr);
66	preempt_enable();
67
68	return true;
69}
70
71#endif /* _ASM_LOONGARCH_KFENCE_H */