summaryrefslogtreecommitdiffstats
path: root/arch/arm/include
diff options
context:
space:
mode:
authorWang Kefeng <wangkefeng.wang@huawei.com>2021-12-03 10:26:33 +0100
committerRussell King (Oracle) <rmk+kernel@armlinux.org.uk>2021-12-17 11:34:38 +0000
commit75969686ec0df23157afe24dc818d7bddb087d78 (patch)
tree75c494737cde3df0c91fcacb3de1d67ff5a89108 /arch/arm/include
parent3c341b217414d1d63718438f2b2fa588cf2b73fc (diff)
downloadlinux-75969686ec0df23157afe24dc818d7bddb087d78.tar.bz2
ARM: 9166/1: Support KFENCE for ARM
Add architecture specific implementation details for KFENCE and enable KFENCE on ARM. In particular, this implements the required interface in <asm/kfence.h>. KFENCE requires that attributes for pages from its memory pool can individually be set. Therefore, force the kfence pool to be mapped at page granularity. Testing this patch using the testcases in kfence_test.c and all passed with or without ARM_LPAE. Acked-by: Marco Elver <elver@google.com> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Diffstat (limited to 'arch/arm/include')
-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 000000000000..7980d0f2271f
--- /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 */