xref: /linux/arch/loongarch/include/asm/kfence.h (revision 151ebcf0797b1a3ba53c8843dc21748c80e098c7)
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 
17 static 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. */
52 static 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(*pte))
57 		return false;
58 
59 	if (protect)
60 		set_pte(pte, __pte(pte_val(*pte) & ~(_PAGE_VALID | _PAGE_PRESENT)));
61 	else
62 		set_pte(pte, __pte(pte_val(*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 */
72