UbiquitousOS
/
OpenCloudOS-Kernel
mirror of https://gitee.com/OpenCloudOS/OpenCloudOS-Kernel.git
11
0
Fork 0
Code Issues Projects Releases Wiki Activity
OpenCloudOS-Kernel/kernel/trace
History
Daniel Xu dd6e10fbd9 bpf: Add bpf_task_pt_regs() helper 
The motivation behind this helper is to access userspace pt_regs in a
kprobe handler.

uprobe's ctx is the userspace pt_regs. kprobe's ctx is the kernelspace
pt_regs. bpf_task_pt_regs() allows accessing userspace pt_regs in a
kprobe handler. The final case (kernelspace pt_regs in uprobe) is
pretty rare (usermode helper) so I think that can be solved later if
necessary.

More concretely, this helper is useful in doing BPF-based DWARF stack
unwinding. Currently the kernel can only do framepointer based stack
unwinds for userspace code. This is because the DWARF state machines are
too fragile to be computed in kernelspace [0]. The idea behind
DWARF-based stack unwinds w/ BPF is to copy a chunk of the userspace
stack (while in prog context) and send it up to userspace for unwinding
(probably with libunwind) [1]. This would effectively enable profiling
applications with -fomit-frame-pointer using kprobes and uprobes.

[0]: https://lkml.org/lkml/2012/2/10/356
[1]: https://github.com/danobi/bpf-dwarf-walk

Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/e2718ced2d51ef4268590ab8562962438ab82815.1629772842.git.dxu@dxuuu.xyz
 		2021-08-25 10:37:05 -07:00
..
Kconfig trace: Add timerlat tracer 2021-06-25 19:57:24 -04:00
Makefile trace: Add osnoise tracer 2021-06-25 19:57:01 -04:00
blktrace.c block-5.12-2021-02-27 2021-02-28 11:23:38 -08:00
bpf_trace.c bpf: Add bpf_task_pt_regs() helper 2021-08-25 10:37:05 -07:00
bpf_trace.h bpf: Use dedicated bpf_trace_printk event instead of trace_printk() 2020-07-13 16:55:49 -07:00
error_report-traces.c tracing: add error_report_end trace point 2021-02-26 09:41:02 -08:00
fgraph.c tracing: Fix various typos in comments 2021-03-23 14:08:18 -04:00
ftrace.c ftrace: Remove redundant initialization of variable ret 2021-07-23 08:46:02 -04:00
ftrace_internal.h x86/ftrace: Have ftrace trampolines turn read-only at the end of system boot up 2020-05-12 18:24:34 -04:00
kprobe_event_gen_test.c tracing: Add kprobe event command generation test module 2020-01-30 09:46:28 -05:00
power-traces.c
…
preemptirq_delay_test.c kernel: trace: preemptirq_delay_test: add cpu affinity 2021-02-02 17:02:07 -05:00
ring_buffer.c tracing: Fix bug in rb_per_cpu_empty() that might cause deadloop. 2021-07-22 11:52:33 -04:00
ring_buffer_benchmark.c sched,tracing: Convert to sched_set_fifo() 2020-07-29 11:43:53 +02:00
rpm-traces.c
…
synth_event_gen_test.c tracing: Fix various typos in comments 2021-03-23 14:08:18 -04:00
trace.c tracing: Fix NULL pointer dereference in start_creating 2021-07-30 18:45:11 -04:00
trace.h Tracing updates for 5.14: 2021-07-03 11:13:22 -07:00
trace_benchmark.c tracing: Fix some typos in comments 2020-11-10 20:39:40 -05:00
trace_benchmark.h
…
trace_boot.c tracing/boot: Add per-group/all events enablement 2021-06-10 11:16:20 -04:00
trace_branch.c tracing: Merge irqflags + preempt counter. 2021-02-02 17:02:06 -05:00
trace_clock.c tracing: Do no increment trace_clock_global() by one 2021-06-18 09:10:00 -04:00
trace_dynevent.c tracing/dynevent: Fix a memory leak in an error handling path 2021-04-13 12:29:48 -04:00
trace_dynevent.h tracing/dynevent: Delegate parsing to create function 2021-02-09 12:52:15 -05:00
trace_entries.h trace: Add timerlat tracer 2021-06-25 19:57:24 -04:00
trace_event_perf.c tracing: Fix various typos in comments 2021-03-23 14:08:18 -04:00
trace_events.c tracing: Fix various typos in comments 2021-03-23 14:08:18 -04:00
trace_events_filter.c tracing: Update create_system_filter() kernel-doc comment 2021-03-25 16:04:35 -04:00
trace_events_filter_test.h
…
trace_events_hist.c tracing: Reject string operand in the histogram expression 2021-08-04 17:49:26 -04:00
trace_events_inject.c tracing: Merge irqflags + preempt counter. 2021-02-02 17:02:06 -05:00
trace_events_synth.c tracing: Clean up alloc_synth_event() 2021-07-23 08:45:30 -04:00
trace_events_trigger.c tracing: Fix set_named_trigger_data() kernel-doc comment 2021-06-10 11:16:20 -04:00
trace_export.c tracing: Fix some typos in comments 2020-11-10 20:39:40 -05:00
trace_functions.c tracing: Add "func_no_repeats" option for function tracing 2021-04-15 14:50:02 -04:00
trace_functions_graph.c tracing: Fix various typos in comments 2021-03-23 14:08:18 -04:00
trace_hwlat.c tracing: Quiet smp_processor_id() use in preemptable warning in hwlat 2021-08-05 09:27:31 -04:00
trace_irqsoff.c tracing: Merge irqflags + preempt counter. 2021-02-02 17:02:06 -05:00
trace_kdb.c tracing: Rename trace_buffer to array_buffer 2020-01-13 13:19:38 -05:00
trace_kprobe.c tracing: Fix various typos in comments 2021-03-23 14:08:18 -04:00
trace_kprobe_selftest.c
…
trace_kprobe_selftest.h
…
trace_mmiotrace.c tracing: Remove definition of DEBUG in trace_mmiotrace.c 2021-02-02 17:02:07 -05:00
trace_nop.c
…
trace_osnoise.c trace/timerlat: Fix indentation on timerlat_main() 2021-06-29 16:37:50 -04:00
trace_output.c trace: Add timerlat tracer 2021-06-25 19:57:24 -04:00
trace_output.h ftrace: Add recording of functions that caused recursion 2020-11-06 08:42:26 -05:00
trace_preemptirq.c lockdep: fix order in trace_hardirqs_off_caller() 2020-09-14 10:08:07 +02:00
trace_printk.c tracing: Add a verifier to check string pointers for trace events 2021-03-18 12:58:27 -04:00
trace_probe.c tracing: Fix various typos in comments 2021-03-23 14:08:18 -04:00
trace_probe.h tracing: Fix various typos in comments 2021-03-23 14:08:18 -04:00
trace_probe_tmpl.h tracing: Fix various typos in comments 2021-03-23 14:08:18 -04:00
trace_recursion_record.c ftrace: Add recording of functions that caused recursion 2020-11-06 08:42:26 -05:00
trace_sched_switch.c tracing: Fix sched switch start/stop refcount racy updates 2020-01-30 09:46:10 -05:00
trace_sched_wakeup.c tracing: Change variable type as bool for clean-up 2021-06-30 09:19:14 -04:00
trace_selftest.c tracing: Fix various typos in comments 2021-03-23 14:08:18 -04:00
trace_selftest_dynamic.c
…
trace_seq.c tracing: Fix various typos in comments 2021-03-23 14:08:18 -04:00
trace_stack.c ftrace: Have the callbacks receive a struct ftrace_regs instead of pt_regs 2020-11-13 12:14:55 -05:00
trace_stat.c tracing: make tracing_init_dentry() returns an integer instead of a d_entry pointer 2020-09-18 22:17:14 -04:00
trace_stat.h tracing: Use generic type for comparator function 2019-11-14 13:15:11 -05:00
trace_synth.h tracing: Synthetic event field_pos is an index not a boolean 2021-07-23 08:43:04 -04:00
trace_syscalls.c tracing: Merge irqflags + preempt counter. 2021-02-02 17:02:06 -05:00
trace_uprobe.c tracing/dynevent: Delegate parsing to create function 2021-02-09 12:52:15 -05:00
tracing_map.c tracing: Fix some typos in comments 2020-11-10 20:39:40 -05:00
tracing_map.h tracing: Fix some typos in comments 2020-11-10 20:39:40 -05:00