d352bd889b
Yonghong Song says:
====================
Currently, btf only supports upto 32bit enum value with BTF_KIND_ENUM.
But in kernel, some enum has 64bit values, e.g., in uapi bpf.h, we have
enum {
BPF_F_INDEX_MASK = 0xffffffffULL,
BPF_F_CURRENT_CPU = BPF_F_INDEX_MASK,
BPF_F_CTXLEN_MASK = (0xfffffULL << 32),
};
With BTF_KIND_ENUM, the value for BPF_F_CTXLEN_MASK will be encoded
as 0 which is incorrect.
To solve this problem, BTF_KIND_ENUM64 is proposed in this patch set
to support enum 64bit values. Also, since sometimes there is a need
to generate C code from btf, e.g., vmlinux.h, btf kflag support
is also added for BTF_KIND_ENUM and BTF_KIND_ENUM64 to indicate
signedness, helping proper value printout.
Changelog:
v4 -> v5:
- skip newly-added enum64 C test if clang version <= 14.
v3 -> v4:
- rename btf_type_is_any_enum() to btf_is_any_enum() to favor
consistency in libbpf.
- fix sign extension issue in btf_dump_get_enum_value().
- fix BPF_CORE_FIELD_SIGNED signedness issue in bpf_core_calc_field_relo().
v2 -> v3:
- Implement separate btf_equal_enum()/btf_equal_enum64() and
btf_compat_enum()/btf_compat_enum64().
- Add a new enum64 placeholder type dynamicly for enum64 sanitization.
- For bpftool output and unit selftest, printed out signed/unsigned
encoding as well.
- fix some issues with BTF_KIND_ENUM is doc and clarified sign extension
rules for enum values.
v1 -> v2:
- Changed kflag default from signed to unsigned
- Fixed sanitization issue
- Broke down libbpf related patches for easier review
- Added more tests
- More code refactorization
- Corresponding llvm patch (to support enum64) is also updated
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.