X-Git-Url: https://repo.jachan.dev/linux.git/blobdiff_plain/adfbb80d38327b04a9cfb1635177dfca90de4a58..71b77a7a27a3:/lib/test_stackinit.c

diff --git a/lib/test_stackinit.c b/lib/test_stackinit.c
index e97dc54b4fdf..f93b1e145ada 100644
--- a/lib/test_stackinit.c
+++ b/lib/test_stackinit.c
@@ -12,7 +12,7 @@
 
 /* Exfiltration buffer. */
 #define MAX_VAR_SIZE	128
-static char check_buf[MAX_VAR_SIZE];
+static u8 check_buf[MAX_VAR_SIZE];
 
 /* Character array to trigger stack protector in all functions. */
 #define VAR_BUFFER	 32
@@ -92,8 +92,9 @@ static bool range_contains(char *haystack_start, size_t haystack_size,
  * @var_type: type to be tested for zeroing initialization
  * @which: is this a SCALAR, STRING, or STRUCT type?
  * @init_level: what kind of initialization is performed
+ * @xfail: is this test expected to fail?
  */
-#define DEFINE_TEST_DRIVER(name, var_type, which)		\
+#define DEFINE_TEST_DRIVER(name, var_type, which, xfail)	\
 /* Returns 0 on success, 1 on failure. */			\
 static noinline __init int test_ ## name (void)			\
 {								\
@@ -106,9 +107,18 @@ static noinline __init int test_ ## name (void)			\
 								\
 	/* Fill clone type with zero for per-field init. */	\
 	memset(&zero, 0x00, sizeof(zero));			\
+	/* Clear entire check buffer for 0xFF overlap test. */	\
+	memset(check_buf, 0x00, sizeof(check_buf));		\
 	/* Fill stack with 0xFF. */				\
 	ignored = leaf_ ##name((unsigned long)&ignored, 1,	\
 				FETCH_ARG_ ## which(zero));	\
+	/* Verify all bytes overwritten with 0xFF. */		\
+	for (sum = 0, i = 0; i < target_size; i++)		\
+		sum += (check_buf[i] != 0xFF);			\
+	if (sum) {						\
+		pr_err(#name ": leaf fill was not 0xFF!?\n");	\
+		return 1;					\
+	}							\
 	/* Clear entire check buffer for later bit tests. */	\
 	memset(check_buf, 0x00, sizeof(check_buf));		\
 	/* Extract stack-defined variable contents. */		\
@@ -126,17 +136,18 @@ static noinline __init int test_ ## name (void)			\
 		return 1;					\
 	}							\
 								\
-	/* Look for any set bits in the check region. */	\
-	for (i = 0; i < sizeof(check_buf); i++)			\
-		sum += (check_buf[i] != 0);			\
+	/* Look for any bytes still 0xFF in check region. */	\
+	for (sum = 0, i = 0; i < target_size; i++)		\
+		sum += (check_buf[i] == 0xFF);			\
 								\
-	if (sum == 0)						\
+	if (sum == 0) {						\
 		pr_info(#name " ok\n");				\
-	else							\
-		pr_warn(#name " FAIL (uninit bytes: %d)\n",	\
-			sum);					\
-								\
-	return (sum != 0);					\
+		return 0;					\
+	} else {						\
+		pr_warn(#name " %sFAIL (uninit bytes: %d)\n",	\
+			(xfail) ? "X" : "", sum);		\
+		return (xfail) ? 0 : 1;				\
+	}							\
 }
 #define DEFINE_TEST(name, var_type, which, init_level)		\
 /* no-op to force compiler into ignoring "uninitialized" vars */\
@@ -162,13 +173,13 @@ static noinline __init int leaf_ ## name(unsigned long sp,	\
 	 * Keep this buffer around to make sure we've got a	\
 	 * stack frame of SOME kind...				\
 	 */							\
-	memset(buf, (char)(sp && 0xff), sizeof(buf));		\
+	memset(buf, (char)(sp & 0xff), sizeof(buf));		\
 	/* Fill variable with 0xFF. */				\
 	if (fill) {						\
 		fill_start = &var;				\
 		fill_size = sizeof(var);			\
 		memset(fill_start,				\
-		       (char)((sp && 0xff) | forced_mask),	\
+		       (char)((sp & 0xff) | forced_mask),	\
 		       fill_size);				\
 	}							\
 								\
@@ -180,7 +191,7 @@ static noinline __init int leaf_ ## name(unsigned long sp,	\
 								\
 	return (int)buf[0] | (int)buf[sizeof(buf) - 1];		\
 }								\
-DEFINE_TEST_DRIVER(name, var_type, which)
+DEFINE_TEST_DRIVER(name, var_type, which, 0)
 
 /* Structure with no padding. */
 struct test_packed {
@@ -317,8 +328,14 @@ static noinline __init int leaf_switch_2_none(unsigned long sp, bool fill,
 	return __leaf_switch_none(2, fill);
 }
 
-DEFINE_TEST_DRIVER(switch_1_none, uint64_t, SCALAR);
-DEFINE_TEST_DRIVER(switch_2_none, uint64_t, SCALAR);
+/*
+ * These are expected to fail for most configurations because neither
+ * GCC nor Clang have a way to perform initialization of variables in
+ * non-code areas (i.e. in a switch statement before the first "case").
+ * https://bugs.llvm.org/show_bug.cgi?id=44916
+ */
+DEFINE_TEST_DRIVER(switch_1_none, uint64_t, SCALAR, 1);
+DEFINE_TEST_DRIVER(switch_2_none, uint64_t, SCALAR, 1);
 
 static int __init test_stackinit_init(void)
 {