From b16d12f3900283e00aded9131ba1e9b2880513c3 Mon Sep 17 00:00:00 2001 From: Ilya Leoshkevich Date: Wed, 13 Oct 2021 18:08:59 +0200 Subject: [PATCH 1/3] selftests/bpf: Use cpu_number only on arches that have it cpu_number exists only on Intel and aarch64, so skip the test involing it on other arches. An alternative would be to replace it with an exported non-ifdefed primitive-typed percpu variable from the common code, but there appears to be none. Signed-off-by: Ilya Leoshkevich Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20211013160902.428340-2-iii@linux.ibm.com --- tools/testing/selftests/bpf/prog_tests/btf_dump.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/btf_dump.c b/tools/testing/selftests/bpf/prog_tests/btf_dump.c index 87f9df653e4e..12f457b6786d 100644 --- a/tools/testing/selftests/bpf/prog_tests/btf_dump.c +++ b/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); } From c9e982b879465ca74e3593ce82808aa259265a71 Mon Sep 17 00:00:00 2001 From: Ilya Leoshkevich Date: Wed, 13 Oct 2021 18:09:00 +0200 Subject: [PATCH 2/3] libbpf: Fix dumping big-endian bitfields On big-endian arches not only bytes, but also bits are numbered in reverse order (see e.g. S/390 ELF ABI Supplement, but this is also true for other big-endian arches as well). Signed-off-by: Ilya Leoshkevich Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20211013160902.428340-3-iii@linux.ibm.com --- tools/lib/bpf/btf_dump.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c index 5ef42f0abed1..679bf34e3f47 100644 --- a/tools/lib/bpf/btf_dump.c +++ b/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 From 961632d5416389a6f2e7478b674ac645c7e3ff01 Mon Sep 17 00:00:00 2001 From: Ilya Leoshkevich Date: Wed, 13 Oct 2021 18:09:01 +0200 Subject: [PATCH 3/3] libbpf: Fix dumping non-aligned __int128 Non-aligned integers are dumped as bitfields, which is supported for at most 64-bit integers. Fix by using the same trick as btf_dump_float_data(): copy non-aligned values to the local buffer. Signed-off-by: Ilya Leoshkevich Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20211013160902.428340-4-iii@linux.ibm.com --- tools/lib/bpf/btf_dump.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c index 679bf34e3f47..e98c201f29b5 100644 --- a/tools/lib/bpf/btf_dump.c +++ b/tools/lib/bpf/btf_dump.c @@ -1670,9 +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; } @@ -1680,8 +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: {