@@ -766,3 +766,12 @@ config PROTECTABLE_MEMORY
     depends on ARCH_HAS_SET_MEMORY
     select GENERIC_ALLOCATOR
     default y
+
+config PROTECTABLE_MEMORY_SELFTEST
+	bool "Run self test for pmalloc memory allocator"
+	depends on ARCH_HAS_SET_MEMORY
+	select PROTECTABLE_MEMORY
+	default n
+	help
+	  Tries to verify that pmalloc works correctly and that the memory
+	  is effectively protected.

@@ -66,6 +66,7 @@ obj-$(CONFIG_SPARSEMEM_VMEMMAP) += sparse-vmemmap.o
 obj-$(CONFIG_SLOB) += slob.o
 obj-$(CONFIG_MMU_NOTIFIER) += mmu_notifier.o
 obj-$(CONFIG_PROTECTABLE_MEMORY) += pmalloc.o
+obj-$(CONFIG_PROTECTABLE_MEMORY_SELFTEST) += pmalloc-selftest.o
 obj-$(CONFIG_KSM) += ksm.o
 obj-$(CONFIG_PAGE_POISONING) += page_poison.o
 obj-$(CONFIG_SLAB) += slab.o

@@ -0,0 +1,63 @@
+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * pmalloc-selftest.c
+ *
+ * (C) Copyright 2018 Huawei Technologies Co. Ltd.
+ * Author: Igor Stoppa <igor.stoppa@huawei.com>
+ */
+
+#include <linux/pmalloc.h>
+#include <linux/mm.h>
+
+#include "pmalloc-selftest.h"
+
+#define SIZE_1 (PAGE_SIZE * 3)
+#define SIZE_2 1000
+
+#define validate_alloc(expected, variable, size)	\
+	pr_notice("must be " expected ": %s",		\
+		  is_pmalloc_object(variable, size) > 0 ? "ok" : "no")
+
+#define is_alloc_ok(variable, size)	\
+	validate_alloc("ok", variable, size)
+
+#define is_alloc_no(variable, size)	\
+	validate_alloc("no", variable, size)
+
+void pmalloc_selftest(void)
+{
+	struct gen_pool *pool_unprot;
+	struct gen_pool *pool_prot;
+	void *var_prot, *var_unprot, *var_vmall;
+
+	pr_notice("pmalloc self-test");
+	pool_unprot = pmalloc_create_pool("unprotected", 0);
+	pool_prot = pmalloc_create_pool("protected", 0);
+	BUG_ON(!(pool_unprot && pool_prot));
+
+	var_unprot = pmalloc(pool_unprot,  SIZE_1 - 1, GFP_KERNEL);
+	var_prot = pmalloc(pool_prot,  SIZE_1, GFP_KERNEL);
+	*(int *)var_prot = 0;
+	var_vmall = vmalloc(SIZE_2);
+	is_alloc_ok(var_unprot, 10);
+	is_alloc_ok(var_unprot, SIZE_1);
+	is_alloc_ok(var_unprot, PAGE_SIZE);
+	is_alloc_no(var_unprot, SIZE_1 + 1);
+	is_alloc_no(var_vmall, 10);
+
+
+	pfree(pool_unprot, var_unprot);
+	vfree(var_vmall);
+
+	pmalloc_protect_pool(pool_prot);
+
+	/* This will intentionally trigger a WARN because the pool being
+	 * destroyed is not protected, which is unusual and should happen
+	 * on error paths only, where probably other warnings are already
+	 * displayed.
+	 */
+	pmalloc_destroy_pool(pool_unprot);
+
+	/* This must not cause WARNings */
+	pmalloc_destroy_pool(pool_prot);
+}

@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * pmalloc-selftest.h
+ *
+ * (C) Copyright 2018 Huawei Technologies Co. Ltd.
+ * Author: Igor Stoppa <igor.stoppa@huawei.com>
+ */
+
+
+#ifndef __MM_PMALLOC_SELFTEST_H
+#define __MM_PMALLOC_SELFTEST_H
+
+
+#ifdef CONFIG_PROTECTABLE_MEMORY_SELFTEST
+
+void pmalloc_selftest(void);
+
+#else
+
+static inline void pmalloc_selftest(void){};
+
+#endif
+
+#endif

@@ -22,6 +22,7 @@
 #include <asm/page.h>
 
 #include <linux/pmalloc.h>
+#include "pmalloc-selftest.h"
 /*
  * pmalloc_data contains the data specific to a pmalloc pool,
  * in a format compatible with the design of gen_alloc.

@@ -492,6 +493,7 @@ static int __init pmalloc_late_init(void)
 		}
 	}
 	mutex_unlock(&pmalloc_mutex);
+	pmalloc_selftest();
 	return 0;
 }
 late_initcall(pmalloc_late_init);