Merge branch 'btf_dump fixes for s390'

Ilya Leoshkevich says:

====================

This series along with [1] and [2] fixes all the failures in the
btf_dump testsuite currently present on s390, in particular:

* [1] fixes intermittent build bug causing "failed to encode tag ..."
  * error messages.
* [2] fixes missing VAR entries on s390.
* Patch 1 disables Intel-specific code in a testcase.
* Patch 2 fixes an endianness-related bug.
* Patch 3 fixes an alignment-related bug.
* Patch 4 improves overly pessimistic alignment handling.

[1] https://lore.kernel.org/bpf/20211012022521.399302-1-iii@linux.ibm.com/
[2] https://lore.kernel.org/bpf/20211012022637.399365-1-iii@linux.ibm.com/

v1: https://lore.kernel.org/bpf/20211012023218.399568-1-iii@linux.ibm.com/
v1 -> v2:
- Remove redundant local variables, use t->size directly instead.

Best regards,
Ilya
====================
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>

tools/lib/bpf/btf_dump.c

@@ -1562,29 +1562,28 @@ static int btf_dump_get_bitfield_value(struct btf_dump *d,
 				       __u64 *value)
 {
 	__u16 left_shift_bits, right_shift_bits;
-	__u8 nr_copy_bits, nr_copy_bytes;
 	const __u8 *bytes = data;
-	int sz = t->size;
+	__u8 nr_copy_bits;
 	__u64 num = 0;
 	int i;
 
 	/* Maximum supported bitfield size is 64 bits */
-	if (sz > 8) {
-		pr_warn("unexpected bitfield size %d\n", sz);
+	if (t->size > 8) {
+		pr_warn("unexpected bitfield size %d\n", t->size);
 		return -EINVAL;
 	}
 
 	/* Bitfield value retrieval is done in two steps; first relevant bytes are
 	 * stored in num, then we left/right shift num to eliminate irrelevant bits.
 	 */
-	nr_copy_bits = bit_sz + bits_offset;
-	nr_copy_bytes = t->size;
 #if __BYTE_ORDER == __LITTLE_ENDIAN
-	for (i = nr_copy_bytes - 1; i >= 0; i--)
+	for (i = t->size - 1; i >= 0; i--)
 		num = num * 256 + bytes[i];
+	nr_copy_bits = bit_sz + bits_offset;
 #elif __BYTE_ORDER == __BIG_ENDIAN
-	for (i = 0; i < nr_copy_bytes; i++)
+	for (i = 0; i < t->size; i++)
 		num = num * 256 + bytes[i];
+	nr_copy_bits = t->size * 8 - bits_offset;
 #else
 # error "Unrecognized __BYTE_ORDER__"
 #endif
@@ -1671,9 +1670,10 @@ static int btf_dump_int_data(struct btf_dump *d,
 {
 	__u8 encoding = btf_int_encoding(t);
 	bool sign = encoding & BTF_INT_SIGNED;
+	char buf[16] __aligned(16);
 	int sz = t->size;
 
-	if (sz == 0) {
+	if (sz == 0 || sz > sizeof(buf)) {
 		pr_warn("unexpected size %d for id [%u]\n", sz, type_id);
 		return -EINVAL;
 	}
@@ -1681,8 +1681,10 @@ static int btf_dump_int_data(struct btf_dump *d,
 	/* handle packed int data - accesses of integers not aligned on
 	 * int boundaries can cause problems on some platforms.
 	 */
-	if (!ptr_is_aligned(data, sz))
-		return btf_dump_bitfield_data(d, t, data, 0, 0);
+	if (!ptr_is_aligned(data, sz)) {
+		memcpy(buf, data, sz);
+		data = buf;
+	}
 
 	switch (sz) {
 	case 16: {

tools/testing/selftests/bpf/prog_tests/btf_dump.c

@@ -778,8 +778,10 @@ static void test_btf_dump_struct_data(struct btf *btf, struct btf_dump *d,
 static void test_btf_dump_var_data(struct btf *btf, struct btf_dump *d,
 				   char *str)
 {
+#if defined(__i386__) || defined(__x86_64__) || defined(__aarch64__)
 	TEST_BTF_DUMP_VAR(btf, d, NULL, str, "cpu_number", int, BTF_F_COMPACT,
 			  "int cpu_number = (int)100", 100);
+#endif
 	TEST_BTF_DUMP_VAR(btf, d, NULL, str, "cpu_profile_flip", int, BTF_F_COMPACT,
 			  "static int cpu_profile_flip = (int)2", 2);
 }