resource, kunit: add test case for region_intersects()

Patch series "resource: Fix region_intersects() vs
add_memory_driver_managed()", v3.

The patchset fixes a bug of region_intersects() for systems with CXL
memory.  The details of the bug can be found in [1/3].  To avoid similar
bugs in the future.  A kunit test case for region_intersects() is added in
[3/3].  [2/3] is a preparation patch for [3/3].


This patch (of 3):

region_intersects() is important because it's used for /dev/mem permission
checking.  To avoid possible bug of region_intersects() in the future, a
kunit test case for region_intersects() is added.

Link: https://lkml.kernel.org/r/20240906030713.204292-1-ying.huang@intel.com
Link: https://lkml.kernel.org/r/20240906030713.204292-4-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Jonathan Cameron <jonathan.cameron@huawei.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Alison Schofield <alison.schofield@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Baoquan He <bhe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

2 files changed, 157 insertions, 6 deletions

diff --git a/kernel/resource.c b/kernel/resource.c
index 5e76b98c9771..4c9cb0363f9a 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -1817,7 +1817,17 @@ EXPORT_SYMBOL(resource_list_free);
 #ifdef CONFIG_GET_FREE_REGION
 #define GFR_DESCENDING		(1UL << 0)
 #define GFR_REQUEST_REGION	(1UL << 1)
-#define GFR_DEFAULT_ALIGN (1UL << PA_SECTION_SHIFT)
+#ifdef PA_SECTION_SHIFT
+#define GFR_DEFAULT_ALIGN	(1UL << PA_SECTION_SHIFT)
+#else
+#define GFR_DEFAULT_ALIGN	PAGE_SIZE
+#endif
+
+#ifdef MAX_PHYSMEM_BITS
+#define MAX_PHYS_ADDR		((1ULL << MAX_PHYSMEM_BITS) - 1)
+#else
+#define MAX_PHYS_ADDR		(-1ULL)
+#endif
 
 static resource_size_t gfr_start(struct resource *base, resource_size_t size,
 				 resource_size_t align, unsigned long flags)
@@ -1825,8 +1835,7 @@ static resource_size_t gfr_start(struct resource *base, resource_size_t size,
 	if (flags & GFR_DESCENDING) {
 		resource_size_t end;
 
-		end = min_t(resource_size_t, base->end,
-			    (1ULL << MAX_PHYSMEM_BITS) - 1);
+		end = min_t(resource_size_t, base->end, MAX_PHYS_ADDR);
 		return end - size + 1;
 	}
 
@@ -1843,8 +1852,7 @@ static bool gfr_continue(struct resource *base, resource_size_t addr,
 	 * @size did not wrap 0.
 	 */
 	return addr > addr - size &&
-	       addr <= min_t(resource_size_t, base->end,
-			     (1ULL << MAX_PHYSMEM_BITS) - 1);
+		addr <= min_t(resource_size_t, base->end, MAX_PHYS_ADDR);
 }
 
 static resource_size_t gfr_next(resource_size_t addr, resource_size_t size,
@@ -2005,7 +2013,7 @@ struct resource *alloc_free_mem_region(struct resource *base,
 	return get_free_mem_region(NULL, base, size, align, name,
 				   IORES_DESC_NONE, flags);
 }
-EXPORT_SYMBOL_NS_GPL(alloc_free_mem_region, CXL);
+EXPORT_SYMBOL_GPL(alloc_free_mem_region);
 #endif /* CONFIG_GET_FREE_REGION */
 
 static int __init strict_iomem(char *str)
diff --git a/kernel/resource_kunit.c b/kernel/resource_kunit.c
index 0e509985a44a..42d2d8d20f5d 100644
--- a/kernel/resource_kunit.c
+++ b/kernel/resource_kunit.c
@@ -7,6 +7,8 @@
 #include <linux/ioport.h>
 #include <linux/kernel.h>
 #include <linux/string.h>
+#include <linux/sizes.h>
+#include <linux/mm.h>
 
 #define R0_START	0x0000
 #define R0_END		0xffff
@@ -137,9 +139,150 @@ static void resource_test_intersection(struct kunit *test)
 	} while (++i < ARRAY_SIZE(results_for_intersection));
 }
 
+/*
+ * The test resource tree for region_intersects() test:
+ *
+ * BASE-BASE+1M-1 : Test System RAM 0
+ *		  # hole 0 (BASE+1M-BASE+2M)
+ * BASE+2M-BASE+3M-1 : Test CXL Window 0
+ * BASE+3M-BASE+4M-1 : Test System RAM 1
+ * BASE+4M-BASE+7M-1 : Test CXL Window 1
+ *   BASE+4M-BASE+5M-1 : Test System RAM 2
+ *     BASE+4M+128K-BASE+4M+256K-1: Test Code
+ *   BASE+5M-BASE+6M-1 : Test System RAM 3
+ */
+#define RES_TEST_RAM0_OFFSET	0
+#define RES_TEST_RAM0_SIZE	SZ_1M
+#define RES_TEST_HOLE0_OFFSET	(RES_TEST_RAM0_OFFSET + RES_TEST_RAM0_SIZE)
+#define RES_TEST_HOLE0_SIZE	SZ_1M
+#define RES_TEST_WIN0_OFFSET	(RES_TEST_HOLE0_OFFSET + RES_TEST_HOLE0_SIZE)
+#define RES_TEST_WIN0_SIZE	SZ_1M
+#define RES_TEST_RAM1_OFFSET	(RES_TEST_WIN0_OFFSET + RES_TEST_WIN0_SIZE)
+#define RES_TEST_RAM1_SIZE	SZ_1M
+#define RES_TEST_WIN1_OFFSET	(RES_TEST_RAM1_OFFSET + RES_TEST_RAM1_SIZE)
+#define RES_TEST_WIN1_SIZE	(SZ_1M * 3)
+#define RES_TEST_RAM2_OFFSET	RES_TEST_WIN1_OFFSET
+#define RES_TEST_RAM2_SIZE	SZ_1M
+#define RES_TEST_CODE_OFFSET	(RES_TEST_RAM2_OFFSET + SZ_128K)
+#define RES_TEST_CODE_SIZE	SZ_128K
+#define RES_TEST_RAM3_OFFSET	(RES_TEST_RAM2_OFFSET + RES_TEST_RAM2_SIZE)
+#define RES_TEST_RAM3_SIZE	SZ_1M
+#define RES_TEST_TOTAL_SIZE	((RES_TEST_WIN1_OFFSET + RES_TEST_WIN1_SIZE))
+
+static void remove_free_resource(void *ctx)
+{
+	struct resource *res = (struct resource *)ctx;
+
+	remove_resource(res);
+	kfree(res);
+}
+
+static void resource_test_request_region(struct kunit *test, struct resource *parent,
+					 resource_size_t start, resource_size_t size,
+					 const char *name, unsigned long flags)
+{
+	struct resource *res;
+
+	res = __request_region(parent, start, size, name, flags);
+	KUNIT_ASSERT_NOT_NULL(test, res);
+	kunit_add_action_or_reset(test, remove_free_resource, res);
+}
+
+static void resource_test_insert_resource(struct kunit *test, struct resource *parent,
+					  resource_size_t start, resource_size_t size,
+					  const char *name, unsigned long flags)
+{
+	struct resource *res;
+
+	res = kzalloc(sizeof(*res), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, res);
+
+	res->name = name;
+	res->start = start;
+	res->end = start + size - 1;
+	res->flags = flags;
+	if (insert_resource(parent, res)) {
+		kfree(res);
+		KUNIT_FAIL_AND_ABORT(test, "Fail to insert resource %pR\n", res);
+	}
+
+	kunit_add_action_or_reset(test, remove_free_resource, res);
+}
+
+static void resource_test_region_intersects(struct kunit *test)
+{
+	unsigned long flags =  IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
+	struct resource *parent;
+	resource_size_t start;
+
+	/* Find an iomem_resource hole to hold test resources */
+	parent = alloc_free_mem_region(&iomem_resource, RES_TEST_TOTAL_SIZE, SZ_1M,
+				       "test resources");
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, parent);
+	start = parent->start;
+	kunit_add_action_or_reset(test, remove_free_resource, parent);
+
+	resource_test_request_region(test, parent, start + RES_TEST_RAM0_OFFSET,
+				     RES_TEST_RAM0_SIZE, "Test System RAM 0", flags);
+	resource_test_insert_resource(test, parent, start + RES_TEST_WIN0_OFFSET,
+				      RES_TEST_WIN0_SIZE, "Test CXL Window 0",
+				      IORESOURCE_MEM);
+	resource_test_request_region(test, parent, start + RES_TEST_RAM1_OFFSET,
+				     RES_TEST_RAM1_SIZE, "Test System RAM 1", flags);
+	resource_test_insert_resource(test, parent, start + RES_TEST_WIN1_OFFSET,
+				      RES_TEST_WIN1_SIZE, "Test CXL Window 1",
+				      IORESOURCE_MEM);
+	resource_test_request_region(test, parent, start + RES_TEST_RAM2_OFFSET,
+				     RES_TEST_RAM2_SIZE, "Test System RAM 2", flags);
+	resource_test_insert_resource(test, parent, start + RES_TEST_CODE_OFFSET,
+				      RES_TEST_CODE_SIZE, "Test Code", flags);
+	resource_test_request_region(test, parent, start + RES_TEST_RAM3_OFFSET,
+				     RES_TEST_RAM3_SIZE, "Test System RAM 3", flags);
+	kunit_release_action(test, remove_free_resource, parent);
+
+	KUNIT_EXPECT_EQ(test, REGION_INTERSECTS,
+			region_intersects(start + RES_TEST_RAM0_OFFSET, PAGE_SIZE,
+					  IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE));
+	KUNIT_EXPECT_EQ(test, REGION_INTERSECTS,
+			region_intersects(start + RES_TEST_RAM0_OFFSET +
+					  RES_TEST_RAM0_SIZE - PAGE_SIZE, 2 * PAGE_SIZE,
+					  IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE));
+	KUNIT_EXPECT_EQ(test, REGION_DISJOINT,
+			region_intersects(start + RES_TEST_HOLE0_OFFSET, PAGE_SIZE,
+					  IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE));
+	KUNIT_EXPECT_EQ(test, REGION_DISJOINT,
+			region_intersects(start + RES_TEST_HOLE0_OFFSET +
+					  RES_TEST_HOLE0_SIZE - PAGE_SIZE, 2 * PAGE_SIZE,
+					  IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE));
+	KUNIT_EXPECT_EQ(test, REGION_MIXED,
+			region_intersects(start + RES_TEST_WIN0_OFFSET +
+					  RES_TEST_WIN0_SIZE - PAGE_SIZE, 2 * PAGE_SIZE,
+					  IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE));
+	KUNIT_EXPECT_EQ(test, REGION_INTERSECTS,
+			region_intersects(start + RES_TEST_RAM1_OFFSET +
+					  RES_TEST_RAM1_SIZE - PAGE_SIZE, 2 * PAGE_SIZE,
+					  IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE));
+	KUNIT_EXPECT_EQ(test, REGION_INTERSECTS,
+			region_intersects(start + RES_TEST_RAM2_OFFSET +
+					  RES_TEST_RAM2_SIZE - PAGE_SIZE, 2 * PAGE_SIZE,
+					  IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE));
+	KUNIT_EXPECT_EQ(test, REGION_INTERSECTS,
+			region_intersects(start + RES_TEST_CODE_OFFSET, PAGE_SIZE,
+					  IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE));
+	KUNIT_EXPECT_EQ(test, REGION_INTERSECTS,
+			region_intersects(start + RES_TEST_RAM2_OFFSET,
+					  RES_TEST_RAM2_SIZE + PAGE_SIZE,
+					  IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE));
+	KUNIT_EXPECT_EQ(test, REGION_MIXED,
+			region_intersects(start + RES_TEST_RAM3_OFFSET,
+					  RES_TEST_RAM3_SIZE + PAGE_SIZE,
+					  IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE));
+}
+
 static struct kunit_case resource_test_cases[] = {
 	KUNIT_CASE(resource_test_union),
 	KUNIT_CASE(resource_test_intersection),
+	KUNIT_CASE(resource_test_region_intersects),
 	{}
 };