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-rw-r--r--lib/memcpy_kunit.c205
1 files changed, 205 insertions, 0 deletions
diff --git a/lib/memcpy_kunit.c b/lib/memcpy_kunit.c
index 7513e6d5dc90..89128551448d 100644
--- a/lib/memcpy_kunit.c
+++ b/lib/memcpy_kunit.c
@@ -292,6 +292,208 @@ static void memset_test(struct kunit *test)
#undef TEST_OP
}
+static u8 large_src[1024];
+static u8 large_dst[2048];
+static const u8 large_zero[2048];
+
+static void set_random_nonzero(struct kunit *test, u8 *byte)
+{
+ int failed_rng = 0;
+
+ while (*byte == 0) {
+ get_random_bytes(byte, 1);
+ KUNIT_ASSERT_LT_MSG(test, failed_rng++, 100,
+ "Is the RNG broken?");
+ }
+}
+
+static void init_large(struct kunit *test)
+{
+
+ /* Get many bit patterns. */
+ get_random_bytes(large_src, ARRAY_SIZE(large_src));
+
+ /* Make sure we have non-zero edges. */
+ set_random_nonzero(test, &large_src[0]);
+ set_random_nonzero(test, &large_src[ARRAY_SIZE(large_src) - 1]);
+
+ /* Explicitly zero the entire destination. */
+ memset(large_dst, 0, ARRAY_SIZE(large_dst));
+}
+
+/*
+ * Instead of an indirect function call for "copy" or a giant macro,
+ * use a bool to pick memcpy or memmove.
+ */
+static void copy_large_test(struct kunit *test, bool use_memmove)
+{
+ init_large(test);
+
+ /* Copy a growing number of non-overlapping bytes ... */
+ for (int bytes = 1; bytes <= ARRAY_SIZE(large_src); bytes++) {
+ /* Over a shifting destination window ... */
+ for (int offset = 0; offset < ARRAY_SIZE(large_src); offset++) {
+ int right_zero_pos = offset + bytes;
+ int right_zero_size = ARRAY_SIZE(large_dst) - right_zero_pos;
+
+ /* Copy! */
+ if (use_memmove)
+ memmove(large_dst + offset, large_src, bytes);
+ else
+ memcpy(large_dst + offset, large_src, bytes);
+
+ /* Did we touch anything before the copy area? */
+ KUNIT_ASSERT_EQ_MSG(test,
+ memcmp(large_dst, large_zero, offset), 0,
+ "with size %d at offset %d", bytes, offset);
+ /* Did we touch anything after the copy area? */
+ KUNIT_ASSERT_EQ_MSG(test,
+ memcmp(&large_dst[right_zero_pos], large_zero, right_zero_size), 0,
+ "with size %d at offset %d", bytes, offset);
+
+ /* Are we byte-for-byte exact across the copy? */
+ KUNIT_ASSERT_EQ_MSG(test,
+ memcmp(large_dst + offset, large_src, bytes), 0,
+ "with size %d at offset %d", bytes, offset);
+
+ /* Zero out what we copied for the next cycle. */
+ memset(large_dst + offset, 0, bytes);
+ }
+ /* Avoid stall warnings if this loop gets slow. */
+ cond_resched();
+ }
+}
+
+static void memcpy_large_test(struct kunit *test)
+{
+ copy_large_test(test, false);
+}
+
+static void memmove_large_test(struct kunit *test)
+{
+ copy_large_test(test, true);
+}
+
+/*
+ * On the assumption that boundary conditions are going to be the most
+ * sensitive, instead of taking a full step (inc) each iteration,
+ * take single index steps for at least the first "inc"-many indexes
+ * from the "start" and at least the last "inc"-many indexes before
+ * the "end". When in the middle, take full "inc"-wide steps. For
+ * example, calling next_step(idx, 1, 15, 3) with idx starting at 0
+ * would see the following pattern: 1 2 3 4 7 10 11 12 13 14 15.
+ */
+static int next_step(int idx, int start, int end, int inc)
+{
+ start += inc;
+ end -= inc;
+
+ if (idx < start || idx + inc > end)
+ inc = 1;
+ return idx + inc;
+}
+
+static void inner_loop(struct kunit *test, int bytes, int d_off, int s_off)
+{
+ int left_zero_pos, left_zero_size;
+ int right_zero_pos, right_zero_size;
+ int src_pos, src_orig_pos, src_size;
+ int pos;
+
+ /* Place the source in the destination buffer. */
+ memcpy(&large_dst[s_off], large_src, bytes);
+
+ /* Copy to destination offset. */
+ memmove(&large_dst[d_off], &large_dst[s_off], bytes);
+
+ /* Make sure destination entirely matches. */
+ KUNIT_ASSERT_EQ_MSG(test, memcmp(&large_dst[d_off], large_src, bytes), 0,
+ "with size %d at src offset %d and dest offset %d",
+ bytes, s_off, d_off);
+
+ /* Calculate the expected zero spans. */
+ if (s_off < d_off) {
+ left_zero_pos = 0;
+ left_zero_size = s_off;
+
+ right_zero_pos = d_off + bytes;
+ right_zero_size = ARRAY_SIZE(large_dst) - right_zero_pos;
+
+ src_pos = s_off;
+ src_orig_pos = 0;
+ src_size = d_off - s_off;
+ } else {
+ left_zero_pos = 0;
+ left_zero_size = d_off;
+
+ right_zero_pos = s_off + bytes;
+ right_zero_size = ARRAY_SIZE(large_dst) - right_zero_pos;
+
+ src_pos = d_off + bytes;
+ src_orig_pos = src_pos - s_off;
+ src_size = right_zero_pos - src_pos;
+ }
+
+ /* Check non-overlapping source is unchanged.*/
+ KUNIT_ASSERT_EQ_MSG(test,
+ memcmp(&large_dst[src_pos], &large_src[src_orig_pos], src_size), 0,
+ "with size %d at src offset %d and dest offset %d",
+ bytes, s_off, d_off);
+
+ /* Check leading buffer contents are zero. */
+ KUNIT_ASSERT_EQ_MSG(test,
+ memcmp(&large_dst[left_zero_pos], large_zero, left_zero_size), 0,
+ "with size %d at src offset %d and dest offset %d",
+ bytes, s_off, d_off);
+ /* Check trailing buffer contents are zero. */
+ KUNIT_ASSERT_EQ_MSG(test,
+ memcmp(&large_dst[right_zero_pos], large_zero, right_zero_size), 0,
+ "with size %d at src offset %d and dest offset %d",
+ bytes, s_off, d_off);
+
+ /* Zero out everything not already zeroed.*/
+ pos = left_zero_pos + left_zero_size;
+ memset(&large_dst[pos], 0, right_zero_pos - pos);
+}
+
+static void memmove_overlap_test(struct kunit *test)
+{
+ /*
+ * Running all possible offset and overlap combinations takes a
+ * very long time. Instead, only check up to 128 bytes offset
+ * into the destination buffer (which should result in crossing
+ * cachelines), with a step size of 1 through 7 to try to skip some
+ * redundancy.
+ */
+ static const int offset_max = 128; /* less than ARRAY_SIZE(large_src); */
+ static const int bytes_step = 7;
+ static const int window_step = 7;
+
+ static const int bytes_start = 1;
+ static const int bytes_end = ARRAY_SIZE(large_src) + 1;
+
+ init_large(test);
+
+ /* Copy a growing number of overlapping bytes ... */
+ for (int bytes = bytes_start; bytes < bytes_end;
+ bytes = next_step(bytes, bytes_start, bytes_end, bytes_step)) {
+
+ /* Over a shifting destination window ... */
+ for (int d_off = 0; d_off < offset_max; d_off++) {
+ int s_start = max(d_off - bytes, 0);
+ int s_end = min_t(int, d_off + bytes, ARRAY_SIZE(large_src));
+
+ /* Over a shifting source window ... */
+ for (int s_off = s_start; s_off < s_end;
+ s_off = next_step(s_off, s_start, s_end, window_step))
+ inner_loop(test, bytes, d_off, s_off);
+
+ /* Avoid stall warnings. */
+ cond_resched();
+ }
+ }
+}
+
static void strtomem_test(struct kunit *test)
{
static const char input[sizeof(unsigned long)] = "hi";
@@ -347,7 +549,10 @@ static void strtomem_test(struct kunit *test)
static struct kunit_case memcpy_test_cases[] = {
KUNIT_CASE(memset_test),
KUNIT_CASE(memcpy_test),
+ KUNIT_CASE(memcpy_large_test),
KUNIT_CASE(memmove_test),
+ KUNIT_CASE(memmove_large_test),
+ KUNIT_CASE(memmove_overlap_test),
KUNIT_CASE(strtomem_test),
{}
};