diff options
Diffstat (limited to 'lib/memcpy_kunit.c')
| -rw-r--r-- | lib/memcpy_kunit.c | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/lib/memcpy_kunit.c b/lib/memcpy_kunit.c index 2b5cc70ac53f..c4a7107edd43 100644 --- a/lib/memcpy_kunit.c +++ b/lib/memcpy_kunit.c @@ -270,6 +270,208 @@ 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"; @@ -325,7 +527,10 @@ 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), {} }; |