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    Merge tag 'trace-v5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace · 95f1fa9e
    Linus Torvalds authored
    Pull tracing updates from Steven Rostedt:
     "New tracing features:
    
       - New PERMANENT flag to ftrace_ops when attaching a callback to a
         function.
    
         As /proc/sys/kernel/ftrace_enabled when set to zero will disable
         all attached callbacks in ftrace, this has a detrimental impact on
         live kernel tracing, as it disables all that it patched. If a
         ftrace_ops is registered to ftrace with the PERMANENT flag set, it
         will prevent ftrace_enabled from being disabled, and if
         ftrace_enabled is already disabled, it will prevent a ftrace_ops
         with PREMANENT flag set from being registered.
    
       - New register_ftrace_direct().
    
         As eBPF would like to register its own trampolines to be called by
         the ftrace nop locations directly, without going through the ftrace
         trampoline, this function has been added. This allows for eBPF
         trampolines to live along side of ftrace, perf, kprobe and live
         patching. It also utilizes the ftrace enabled_functions file that
         keeps track of functions that have been modified in the kernel, to
         allow for security auditing.
    
       - Allow for kernel internal use of ftrace instances.
    
         Subsystems in the kernel can now create and destroy their own
         tracing instances which allows them to have their own tracing
         buffer, and be able to record events without worrying about other
         users from writing over their data.
    
       - New seq_buf_hex_dump() that lets users use the hex_dump() in their
         seq_buf usage.
    
       - Notifications now added to tracing_max_latency to allow user space
         to know when a new max latency is hit by one of the latency
         tracers.
    
       - Wider spread use of generic compare operations for use of bsearch
         and friends.
    
       - More synthetic event fields may be defined (32 up from 16)
    
       - Use of xarray for architectures with sparse system calls, for the
         system call trace events.
    
      This along with small clean ups and fixes"
    
    * tag 'trace-v5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (51 commits)
      tracing: Enable syscall optimization for MIPS
      tracing: Use xarray for syscall trace events
      tracing: Sample module to demonstrate kernel access to Ftrace instances.
      tracing: Adding new functions for kernel access to Ftrace instances
      tracing: Fix Kconfig indentation
      ring-buffer: Fix typos in function ring_buffer_producer
      ftrace: Use BIT() macro
      ftrace: Return ENOTSUPP when DYNAMIC_FTRACE_WITH_DIRECT_CALLS is not configured
      ftrace: Rename ftrace_graph_stub to ftrace_stub_graph
      ftrace: Add a helper function to modify_ftrace_direct() to allow arch optimization
      ftrace: Add helper find_direct_entry() to consolidate code
      ftrace: Add another check for match in register_ftrace_direct()
      ftrace: Fix accounting bug with direct->count in register_ftrace_direct()
      ftrace/selftests: Fix spelling mistake "wakeing" -> "waking"
      tracing: Increase SYNTH_FIELDS_MAX for synthetic_events
      ftrace/samples: Add a sample module that implements modify_ftrace_direct()
      ftrace: Add modify_ftrace_direct()
      tracing: Add missing "inline" in stub function of latency_fsnotify()
      tracing: Remove stray tab in TRACE_EVAL_MAP_FILE's help text
      tracing: Use seq_buf_hex_dump() to dump buffers
      ...
    95f1fa9e