linux.git/tools/lib/bpf/btf_dump.c, branch v5.16

libbpf: Use __BYTE_ORDER__

2021-10-26T03:39:41+00:00

Use the compiler-defined __BYTE_ORDER__ instead of the libc-defined
__BYTE_ORDER for consistency.

Signed-off-by: Ilya Leoshkevich 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20211026010831.748682-3-iii@linux.ibm.com

libbpf: Add btf__type_cnt() and btf__raw_data() APIs

2021-10-22T23:09:14+00:00

Add btf__type_cnt() and btf__raw_data() APIs and deprecate
btf__get_nr_type() and btf__get_raw_data() since the old APIs
don't follow the libbpf naming convention for getters which
omit 'get' in the name (see [0]). btf__raw_data() is just an
alias to the existing btf__get_raw_data(). btf__type_cnt()
now returns the number of all types of the BTF object
including 'void'.

  [0] Closes: https://github.com/libbpf/libbpf/issues/279

Signed-off-by: Hengqi Chen 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20211022130623.1548429-2-hengqi.chen@gmail.com

libbpf: Fix the use of aligned attribute

2021-10-22T21:24:36+00:00

Building libbpf sources out of kernel tree (in Github repo) we run into
compilation error due to unknown __aligned attribute. It must be coming
from some kernel header, which is not available to Github sources. Use
explicit __attribute__((aligned(16))) instead.

Fixes: 961632d54163 ("libbpf: Fix dumping non-aligned __int128")
Signed-off-by: Andrii Nakryiko 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20211022192502.2975553-1-andrii@kernel.org

libbpf: Fix ptr_is_aligned() usages

2021-10-21T22:50:04+00:00

Currently ptr_is_aligned() takes size, and not alignment, as a
parameter, which may be overly pessimistic e.g. for __i128 on s390,
which must be only 8-byte aligned. Fix by using btf__align_of().

Signed-off-by: Ilya Leoshkevich 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20211021104658.624944-2-iii@linux.ibm.com

libbpf: Fix dumping non-aligned __int128

2021-10-20T18:40:45+00:00

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

libbpf: Fix dumping big-endian bitfields

2021-10-20T18:40:01+00:00

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

bpf: Rename BTF_KIND_TAG to BTF_KIND_DECL_TAG

2021-10-19T01:35:36+00:00

Patch set [1] introduced BTF_KIND_TAG to allow tagging
declarations for struct/union, struct/union field, var, func
and func arguments and these tags will be encoded into
dwarf. They are also encoded to btf by llvm for the bpf target.

After BTF_KIND_TAG is introduced, we intended to use it
for kernel __user attributes. But kernel __user is actually
a type attribute. Upstream and internal discussion showed
it is not a good idea to mix declaration attribute and
type attribute. So we proposed to introduce btf_type_tag
as a type attribute and existing btf_tag renamed to
btf_decl_tag ([2]).

This patch renamed BTF_KIND_TAG to BTF_KIND_DECL_TAG and some
other declarations with *_tag to *_decl_tag to make it clear
the tag is for declaration. In the future, BTF_KIND_TYPE_TAG
might be introduced per [3].

 [1] https://lore.kernel.org/bpf/20210914223004.244411-1-yhs@fb.com/
 [2] https://reviews.llvm.org/D111588
 [3] https://reviews.llvm.org/D111199

Fixes: b5ea834dde6b ("bpf: Support for new btf kind BTF_KIND_TAG")
Fixes: 5b84bd10363e ("libbpf: Add support for BTF_KIND_TAG")
Fixes: 5c07f2fec003 ("bpftool: Add support for BTF_KIND_TAG")
Signed-off-by: Yonghong Song 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20211012164838.3345699-1-yhs@fb.com

libbpf: Add support for BTF_KIND_TAG

2021-09-15T01:45:52+00:00

Add BTF_KIND_TAG support for parsing and dedup.
Also added sanitization for BTF_KIND_TAG. If BTF_KIND_TAG is not
supported in the kernel, sanitize it to INTs.

Signed-off-by: Yonghong Song 
Signed-off-by: Alexei Starovoitov 
Acked-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20210914223025.246687-1-yhs@fb.com

libbpf: Propagate errors when retrieving enum value for typed data display

2021-07-20T20:49:25+00:00

When retrieving the enum value associated with typed data during
"is data zero?" checking in btf_dump_type_data_check_zero(), the
return value of btf_dump_get_enum_value() is not passed to the caller
if the function returns a non-zero (error) value.  Currently, 0
is returned if the function returns an error.  We should instead
propagate the error to the caller.

Signed-off-by: Alan Maguire 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/1626770993-11073-4-git-send-email-alan.maguire@oracle.com

libbpf: Avoid use of __int128 in typed dump display

2021-07-20T20:49:25+00:00

__int128 is not supported for some 32-bit platforms (arm and i386).
__int128 was used in carrying out computations on bitfields which
aid display, but the same calculations could be done with __u64
with the small effect of not supporting 128-bit bitfields.

With these changes, a big-endian issue with casting 128-bit integers
to 64-bit for enum bitfields is solved also, as we now use 64-bit
integers for bitfield calculations.

Reported-by: Naresh Kamboju 
Reported-by: Linux Kernel Functional Testing 
Signed-off-by: Alan Maguire 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/1626770993-11073-2-git-send-email-alan.maguire@oracle.com