1 files changed, 61 insertions, 0 deletions

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 6f9d8898a025..9813f2a9c825 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -24,6 +24,7 @@
 #include <linux/mm.h>
 #include <linux/vmalloc.h>
 #include <linux/set_memory.h>
+#include <linux/kfence.h>
 
 #include <asm/barrier.h>
 #include <asm/cputype.h>
@@ -38,6 +39,7 @@
 #include <asm/ptdump.h>
 #include <asm/tlbflush.h>
 #include <asm/pgalloc.h>
+#include <asm/kfence.h>
 
 #define NO_BLOCK_MAPPINGS	BIT(0)
 #define NO_CONT_MAPPINGS	BIT(1)
@@ -525,12 +527,67 @@ static int __init enable_crash_mem_map(char *arg)
 }
 early_param("crashkernel", enable_crash_mem_map);
 
+#ifdef CONFIG_KFENCE
+
+bool __ro_after_init kfence_early_init = !!CONFIG_KFENCE_SAMPLE_INTERVAL;
+
+/* early_param() will be parsed before map_mem() below. */
+static int __init parse_kfence_early_init(char *arg)
+{
+	int val;
+
+	if (get_option(&arg, &val))
+		kfence_early_init = !!val;
+	return 0;
+}
+early_param("kfence.sample_interval", parse_kfence_early_init);
+
+static phys_addr_t __init arm64_kfence_alloc_pool(void)
+{
+	phys_addr_t kfence_pool;
+
+	if (!kfence_early_init)
+		return 0;
+
+	kfence_pool = memblock_phys_alloc(KFENCE_POOL_SIZE, PAGE_SIZE);
+	if (!kfence_pool) {
+		pr_err("failed to allocate kfence pool\n");
+		kfence_early_init = false;
+		return 0;
+	}
+
+	/* Temporarily mark as NOMAP. */
+	memblock_mark_nomap(kfence_pool, KFENCE_POOL_SIZE);
+
+	return kfence_pool;
+}
+
+static void __init arm64_kfence_map_pool(phys_addr_t kfence_pool, pgd_t *pgdp)
+{
+	if (!kfence_pool)
+		return;
+
+	/* KFENCE pool needs page-level mapping. */
+	__map_memblock(pgdp, kfence_pool, kfence_pool + KFENCE_POOL_SIZE,
+			pgprot_tagged(PAGE_KERNEL),
+			NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS);
+	memblock_clear_nomap(kfence_pool, KFENCE_POOL_SIZE);
+	__kfence_pool = phys_to_virt(kfence_pool);
+}
+#else /* CONFIG_KFENCE */
+
+static inline phys_addr_t arm64_kfence_alloc_pool(void) { return 0; }
+static inline void arm64_kfence_map_pool(phys_addr_t kfence_pool, pgd_t *pgdp) { }
+
+#endif /* CONFIG_KFENCE */
+
 static void __init map_mem(pgd_t *pgdp)
 {
 	static const u64 direct_map_end = _PAGE_END(VA_BITS_MIN);
 	phys_addr_t kernel_start = __pa_symbol(_stext);
 	phys_addr_t kernel_end = __pa_symbol(__init_begin);
 	phys_addr_t start, end;
+	phys_addr_t early_kfence_pool;
 	int flags = NO_EXEC_MAPPINGS;
 	u64 i;
 
@@ -543,6 +600,8 @@ static void __init map_mem(pgd_t *pgdp)
 	 */
 	BUILD_BUG_ON(pgd_index(direct_map_end - 1) == pgd_index(direct_map_end));
 
+	early_kfence_pool = arm64_kfence_alloc_pool();
+
 	if (can_set_direct_map())
 		flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
 
@@ -608,6 +667,8 @@ static void __init map_mem(pgd_t *pgdp)
 		}
 	}
 #endif
+
+	arm64_kfence_map_pool(early_kfence_pool, pgdp);
 }
 
 void mark_rodata_ro(void)