[PATCH v3 3/6] kselftest/arm64: mte: user_mem: check different offsets and sizes

[Joey Gouly <joey.gouly@arm.com>]

To check there are no assumptions in the kernel about buffer sizes or alignments of
user space pointers, expand the test to cover different sizes and offsets.

Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Tested-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
---
 .../selftests/arm64/mte/check_user_mem.c      | 45 +++++++++++--------
 1 file changed, 27 insertions(+), 18 deletions(-)

diff --git a/tools/testing/selftests/arm64/mte/check_user_mem.c b/tools/testing/selftests/arm64/mte/check_user_mem.c
index 2afcc9fb9ae8..89c861ee68fa 100644
--- a/tools/testing/selftests/arm64/mte/check_user_mem.c
+++ b/tools/testing/selftests/arm64/mte/check_user_mem.c
@@ -26,6 +26,8 @@ static int check_usermem_access_fault(int mem_type, int mode, int mapping,
 	char val = 'A';
 	size_t len, read_len;
 	void *ptr, *ptr_next;
+	int fileoff, ptroff, size;
+	int sizes[] = {1, 2, 3, 8, 16, 32, 4096, page_sz};
 
 	err = KSFT_PASS;
 	len = 2 * page_sz;
@@ -62,24 +64,31 @@ static int check_usermem_access_fault(int mem_type, int mode, int mapping,
 	ptr_next = mte_insert_new_tag(ptr_next);
 	mte_set_tag_address_range(ptr_next, tag_len);
 
-	lseek(fd, 0, 0);
-	/* Copy from file into buffer with invalid tag */
-	read_len = read(fd, ptr, len);
-	mte_wait_after_trig();
-	/*
-	 * Accessing user memory in kernel with invalid tag should fail in sync
-	 * mode without fault but may not fail in async mode as per the
-	 * implemented MTE userspace support in Arm64 kernel.
-	 */
-	if (cur_mte_cxt.fault_valid)
-		goto usermem_acc_err;
-
-	if (mode == MTE_SYNC_ERR && read_len < len) {
-		/* test passed */
-	} else if (mode == MTE_ASYNC_ERR && read_len == len) {
-		/* test passed */
-	} else {
-		goto usermem_acc_err;
+	for (fileoff = 0; fileoff < 16; fileoff++) {
+		for (ptroff = 0; ptroff < 16; ptroff++) {
+			for (i = 0; i < ARRAY_SIZE(sizes); i++) {
+				size = sizes[i];
+				lseek(fd, 0, 0);
+				/* Copy from file into buffer with invalid tag */
+				read_len = read(fd, ptr + ptroff, size);
+				mte_wait_after_trig();
+				/*
+				 * Accessing user memory in kernel with invalid tag should fail in sync
+				 * mode without fault but may not fail in async mode as per the
+				 * implemented MTE userspace support in Arm64 kernel.
+				 */
+				if (cur_mte_cxt.fault_valid) {
+					goto usermem_acc_err;
+				}
+				if (mode == MTE_SYNC_ERR && read_len < len) {
+					/* test passed */
+				} else if (mode == MTE_ASYNC_ERR && read_len == size) {
+					/* test passed */
+				} else {
+					goto usermem_acc_err;
+				}
+			}
+		}
 	}
 
 	goto exit;
-- 
2.17.1


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