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Merge tag 'bpf-next-6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Pull bpf updates from Alexei Starovoitov:
- Introduce '__attribute__((bpf_fastcall))' for helpers and kfuncs with
corresponding support in LLVM.
It is similar to existing 'no_caller_saved_registers' attribute in
GCC/LLVM with a provision for backward compatibility. It allows
compilers generate more efficient BPF code assuming the verifier or
JITs will inline or partially inline a helper/kfunc with such
attribute. bpf_cast_to_kern_ctx, bpf_rdonly_cast,
bpf_get_smp_processor_id are the first set of such helpers.
- Harden and extend ELF build ID parsing logic.
When called from sleepable context the relevants parts of ELF file
will be read to find and fetch .note.gnu.build-id information. Also
harden the logic to avoid TOCTOU, overflow, out-of-bounds problems.
- Improvements and fixes for sched-ext:
- Allow passing BPF iterators as kfunc arguments
- Make the pointer returned from iter_next method trusted
- Fix x86 JIT convergence issue due to growing/shrinking conditional
jumps in variable length encoding
- BPF_LSM related:
- Introduce few VFS kfuncs and consolidate them in
fs/bpf_fs_kfuncs.c
- Enforce correct range of return values from certain LSM hooks
- Disallow attaching to other LSM hooks
- Prerequisite work for upcoming Qdisc in BPF:
- Allow kptrs in program provided structs
- Support for gen_epilogue in verifier_ops
- Important fixes:
- Fix uprobe multi pid filter check
- Fix bpf_strtol and bpf_strtoul helpers
- Track equal scalars history on per-instruction level
- Fix tailcall hierarchy on x86 and arm64
- Fix signed division overflow to prevent INT_MIN/-1 trap on x86
- Fix get kernel stack in BPF progs attached to tracepoint:syscall
- Selftests:
- Add uprobe bench/stress tool
- Generate file dependencies to drastically improve re-build time
- Match JIT-ed and BPF asm with __xlated/__jited keywords
- Convert older tests to test_progs framework
- Add support for RISC-V
- Few fixes when BPF programs are compiled with GCC-BPF backend
(support for GCC-BPF in BPF CI is ongoing in parallel)
- Add traffic monitor
- Enable cross compile and musl libc
* tag 'bpf-next-6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (260 commits)
btf: require pahole 1.21+ for DEBUG_INFO_BTF with default DWARF version
btf: move pahole check in scripts/link-vmlinux.sh to lib/Kconfig.debug
btf: remove redundant CONFIG_BPF test in scripts/link-vmlinux.sh
bpf: Call the missed kfree() when there is no special field in btf
bpf: Call the missed btf_record_free() when map creation fails
selftests/bpf: Add a test case to write mtu result into .rodata
selftests/bpf: Add a test case to write strtol result into .rodata
selftests/bpf: Rename ARG_PTR_TO_LONG test description
selftests/bpf: Fix ARG_PTR_TO_LONG {half-,}uninitialized test
bpf: Zero former ARG_PTR_TO_{LONG,INT} args in case of error
bpf: Improve check_raw_mode_ok test for MEM_UNINIT-tagged types
bpf: Fix helper writes to read-only maps
bpf: Remove truncation test in bpf_strtol and bpf_strtoul helpers
bpf: Fix bpf_strtol and bpf_strtoul helpers for 32bit
selftests/bpf: Add tests for sdiv/smod overflow cases
bpf: Fix a sdiv overflow issue
libbpf: Add bpf_object__token_fd accessor
docs/bpf: Add missing BPF program types to docs
docs/bpf: Add constant values for linkages
bpf: Use fake pt_regs when doing bpf syscall tracepoint tracing
...
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| linux | ||
| README | ||
Why we want a copy of kernel headers in tools?
==============================================
There used to be no copies, with tools/ code using kernel headers
directly. From time to time tools/perf/ broke due to legitimate kernel
hacking. At some point Linus complained about such direct usage. Then we
adopted the current model.
The way these headers are used in perf are not restricted to just
including them to compile something.
There are sometimes used in scripts that convert defines into string
tables, etc, so some change may break one of these scripts, or new MSRs
may use some different #define pattern, etc.
E.g.:
$ ls -1 tools/perf/trace/beauty/*.sh | head -5
tools/perf/trace/beauty/arch_errno_names.sh
tools/perf/trace/beauty/drm_ioctl.sh
tools/perf/trace/beauty/fadvise.sh
tools/perf/trace/beauty/fsconfig.sh
tools/perf/trace/beauty/fsmount.sh
$
$ tools/perf/trace/beauty/fadvise.sh
static const char *fadvise_advices[] = {
[0] = "NORMAL",
[1] = "RANDOM",
[2] = "SEQUENTIAL",
[3] = "WILLNEED",
[4] = "DONTNEED",
[5] = "NOREUSE",
};
$
The tools/perf/check-headers.sh script, part of the tools/ build
process, points out changes in the original files.
So its important not to touch the copies in tools/ when doing changes in
the original kernel headers, that will be done later, when
check-headers.sh inform about the change to the perf tools hackers.
Another explanation from Ingo Molnar:
It's better than all the alternatives we tried so far:
- Symbolic links and direct #includes: this was the original approach but
was pushed back on from the kernel side, when tooling modified the
headers and broke them accidentally for kernel builds.
- Duplicate self-defined ABI headers like glibc: double the maintenance
burden, double the chance for mistakes, plus there's no tech-driven
notification mechanism to look at new kernel side changes.
What we are doing now is a third option:
- A software-enforced copy-on-write mechanism of kernel headers to
tooling, driven by non-fatal warnings on the tooling side build when
kernel headers get modified:
Warning: Kernel ABI header differences:
diff -u tools/include/uapi/drm/i915_drm.h include/uapi/drm/i915_drm.h
diff -u tools/include/uapi/linux/fs.h include/uapi/linux/fs.h
diff -u tools/include/uapi/linux/kvm.h include/uapi/linux/kvm.h
...
The tooling policy is to always pick up the kernel side headers as-is,
and integate them into the tooling build. The warnings above serve as a
notification to tooling maintainers that there's changes on the kernel
side.
We've been using this for many years now, and it might seem hacky, but
works surprisingly well.