arch/loongarch/include/asm/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 <asm/pgtable.h>
  14 #include <asm/tlb.h>
  15
  16 static 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. */
  51 static 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 */