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 *kfence_pool = __kfence_pool;
  20         struct vm_struct *area;
  21
  22         area = __get_vm_area_caller(KFENCE_POOL_SIZE, VM_IOREMAP,
  23                                     KFENCE_AREA_START, KFENCE_AREA_END,
  24                                     __builtin_return_address(0));
  25         if (!area)
  26                 return false;
  27
  28         __kfence_pool = (char *)area->addr;
  29         err = ioremap_page_range((unsigned long)__kfence_pool,
  30                                  (unsigned long)__kfence_pool + KFENCE_POOL_SIZE,
  31                                  virt_to_phys((void *)kfence_pool), PAGE_KERNEL);
  32         if (err) {
  33                 free_vm_area(area);
  34                 __kfence_pool = kfence_pool;
  35                 return false;
  36         }
  37
  38         return true;
  39 }
  40
  41 /* Protect the given page and flush TLB. */
  42 static inline bool kfence_protect_page(unsigned long addr, bool protect)
  43 {
  44         pte_t *pte = virt_to_kpte(addr);
  45
  46         if (WARN_ON(!pte) || pte_none(*pte))
  47                 return false;
  48
  49         if (protect)
  50                 set_pte(pte, __pte(pte_val(*pte) & ~(_PAGE_VALID | _PAGE_PRESENT)));
  51         else
  52                 set_pte(pte, __pte(pte_val(*pte) | (_PAGE_VALID | _PAGE_PRESENT)));
  53
  54         preempt_disable();
  55         local_flush_tlb_one(addr);
  56         preempt_enable();
  57
  58         return true;
  59 }
  60
  61 #endif /* _ASM_LOONGARCH_KFENCE_H */