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-rw-r--r--arch/arm/include/asm/kfence.h53
1 files changed, 53 insertions, 0 deletions
diff --git a/arch/arm/include/asm/kfence.h b/arch/arm/include/asm/kfence.h
new file mode 100644
index 000000000..7980d0f22
--- /dev/null
+++ b/arch/arm/include/asm/kfence.h
@@ -0,0 +1,53 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __ASM_ARM_KFENCE_H
+#define __ASM_ARM_KFENCE_H
+
+#include <linux/kfence.h>
+
+#include <asm/pgalloc.h>
+#include <asm/set_memory.h>
+
+static inline int split_pmd_page(pmd_t *pmd, unsigned long addr)
+{
+ int i;
+ unsigned long pfn = PFN_DOWN(__pa(addr));
+ pte_t *pte = pte_alloc_one_kernel(&init_mm);
+
+ if (!pte)
+ return -ENOMEM;
+
+ for (i = 0; i < PTRS_PER_PTE; i++)
+ set_pte_ext(pte + i, pfn_pte(pfn + i, PAGE_KERNEL), 0);
+ pmd_populate_kernel(&init_mm, pmd, pte);
+
+ flush_tlb_kernel_range(addr, addr + PMD_SIZE);
+ return 0;
+}
+
+static inline bool arch_kfence_init_pool(void)
+{
+ unsigned long addr;
+ pmd_t *pmd;
+
+ for (addr = (unsigned long)__kfence_pool; is_kfence_address((void *)addr);
+ addr += PAGE_SIZE) {
+ pmd = pmd_off_k(addr);
+
+ if (pmd_leaf(*pmd)) {
+ if (split_pmd_page(pmd, addr & PMD_MASK))
+ return false;
+ }
+ }
+
+ return true;
+}
+
+static inline bool kfence_protect_page(unsigned long addr, bool protect)
+{
+ set_memory_valid(addr, 1, !protect);
+
+ return true;
+}
+
+#endif /* __ASM_ARM_KFENCE_H */