Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Alexei Starovoitov says:

====================
pull-request: bpf-next 2021-09-17

We've added 63 non-merge commits during the last 12 day(s) which contain
a total of 65 files changed, 2653 insertions(+), 751 deletions(-).

The main changes are:

1) Streamline internal BPF program sections handling and
   bpf_program__set_attach_target() in libbpf, from Andrii.

2) Add support for new btf kind BTF_KIND_TAG, from Yonghong.

3) Introduce bpf_get_branch_snapshot() to capture LBR, from Song.

4) IMUL optimization for x86-64 JIT, from Jie.

5) xsk selftest improvements, from Magnus.

6) Introduce legacy kprobe events support in libbpf, from Rafael.

7) Access hw timestamp through BPF's __sk_buff, from Vadim.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (63 commits)
  selftests/bpf: Fix a few compiler warnings
  libbpf: Constify all high-level program attach APIs
  libbpf: Schedule open_opts.attach_prog_fd deprecation since v0.7
  selftests/bpf: Switch fexit_bpf2bpf selftest to set_attach_target() API
  libbpf: Allow skipping attach_func_name in bpf_program__set_attach_target()
  libbpf: Deprecated bpf_object_open_opts.relaxed_core_relocs
  selftests/bpf: Stop using relaxed_core_relocs which has no effect
  libbpf: Use pre-setup sec_def in libbpf_find_attach_btf_id()
  bpf: Update bpf_get_smp_processor_id() documentation
  libbpf: Add sphinx code documentation comments
  selftests/bpf: Skip btf_tag test if btf_tag attribute not supported
  docs/bpf: Add documentation for BTF_KIND_TAG
  selftests/bpf: Add a test with a bpf program with btf_tag attributes
  selftests/bpf: Test BTF_KIND_TAG for deduplication
  selftests/bpf: Add BTF_KIND_TAG unit tests
  selftests/bpf: Change NAME_NTH/IS_NAME_NTH for BTF_KIND_TAG format
  selftests/bpf: Test libbpf API function btf__add_tag()
  bpftool: Add support for BTF_KIND_TAG
  libbpf: Add support for BTF_KIND_TAG
  libbpf: Rename btf_{hash,equal}_int to btf_{hash,equal}_int_tag
  ...
====================

Link: https://lore.kernel.org/r/20210917173738.3397064-1-ast@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 23 insertions, 0 deletions

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index fe156a8170aa..0cbc5dfe1110 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -57,6 +57,7 @@ struct perf_guest_info_callbacks {
 #include <linux/cgroup.h>
 #include <linux/refcount.h>
 #include <linux/security.h>
+#include <linux/static_call.h>
 #include <asm/local.h>
 
 struct perf_callchain_entry {
@@ -1612,4 +1613,26 @@ extern void __weak arch_perf_update_userpage(struct perf_event *event,
 extern __weak u64 arch_perf_get_page_size(struct mm_struct *mm, unsigned long addr);
 #endif
 
+/*
+ * Snapshot branch stack on software events.
+ *
+ * Branch stack can be very useful in understanding software events. For
+ * example, when a long function, e.g. sys_perf_event_open, returns an
+ * errno, it is not obvious why the function failed. Branch stack could
+ * provide very helpful information in this type of scenarios.
+ *
+ * On software event, it is necessary to stop the hardware branch recorder
+ * fast. Otherwise, the hardware register/buffer will be flushed with
+ * entries of the triggering event. Therefore, static call is used to
+ * stop the hardware recorder.
+ */
+
+/*
+ * cnt is the number of entries allocated for entries.
+ * Return number of entries copied to .
+ */
+typedef int (perf_snapshot_branch_stack_t)(struct perf_branch_entry *entries,
+					   unsigned int cnt);
+DECLARE_STATIC_CALL(perf_snapshot_branch_stack, perf_snapshot_branch_stack_t);
+
 #endif /* _LINUX_PERF_EVENT_H */