arch/loongarch/include/asm/kfence.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * KFENCE support for LoongArch.
   4  *
   5  * Author: Enze Li <[email protected]>
   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(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 */