Messages in this thread | | | From | Jeff Xie <> | Date | Fri, 25 Nov 2022 13:02:04 +0800 | Subject | Re: [PATCH RESEND v8 0/9] LoongArch: Add ftrace support |
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On Sat, Nov 19, 2022 at 1:21 PM Huacai Chen <chenhuacai@kernel.org> wrote: > > Hi, Qing, > > I have applied this series to > https://github.com/loongson/linux/commits/loongarch-next with some > slight modifications, please test that branch to see if everything is > correct.
I found the call trace relative issue for the branch: https://github.com/loongson/linux/commits/loongarch-next
test01:
[root@loongarch tracing]# echo do_sys_openat2 > ./set_ftrace_filter [root@loongarch tracing]# echo 1 > ./options/func_stack_trace [root@loongarch tracing]# echo function > ./current_tracer [root@loongarch tracing]# cat ./trace # tracer: function # # entries-in-buffer/entries-written: 6/6 #P:1 # # _-----=> irqs-off/BH-disabled # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / _-=> migrate-disable # |||| / delay # TASK-PID CPU# ||||| TIMESTAMP FUNCTION # | | | ||||| | | sh-84 [000] ..... 37.784924: do_sys_openat2 <-sys_openat sh-84 [000] ..... 37.786382: <stack trace> => sys_openat => do_syscall => handle_syscall => 0 // abnormal output
test02:
[root@loongarch tracing]# echo do_sys_openat2:stacktrace > ./set_ftrace_filter [root@loongarch tracing]# cat ./trace # tracer: nop # # entries-in-buffer/entries-written: 3/3 #P:1 # # _-----=> irqs-off/BH-disabled # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / _-=> migrate-disable # |||| / delay # TASK-PID CPU# ||||| TIMESTAMP FUNCTION # | | | ||||| | | sh-84 [000] .n.2. 107.946986: <stack trace> => do_syscall => handle_syscall => 0xd9ad812ae sh-84 [000] ...2. 110.584354: <stack trace> => do_syscall => handle_syscall => 0xd9ad812ae // abnormal output
test03:
[root@loongarch tracing]# echo 1 > ./options/stacktrace [root@loongarch tracing]# echo 1 > ./events/sched/sched_switch/enable [root@loongarch tracing]# cat ./trace ... <idle>-0 [000] d..2. 27.981495: sched_switch: prev_comm=swapper/0 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=rcu_preempt next _pid=15 next_prio=120 <idle>-0 [000] d..2. 27.981508: <stack trace> => __schedule => schedule_idle => cpu_startup_entry => kernel_init => 0x0074706d // abnormal output
> > Huacai > > On Wed, Nov 16, 2022 at 4:23 PM Qing Zhang <zhangqing@loongson.cn> wrote: > > > > This patch series to support basic and dynamic ftrace. > > > > 1) -pg > > Use `-pg` makes stub like a child function `void _mcount(void *ra)`. > > Thus, it can be seen store RA and open stack before `call _mcount`. > > Find `open stack` at first, and then find `store RA`. > > > > 2) -fpatchable-function-entry=2 > > The compiler has inserted 2 NOPs before the regular function prologue. > > T series registers are available and safe because of LoongArch psABI. > > > > At runtime, replace nop with bl to enable ftrace call and replace bl with > > nop to disable ftrace call. The bl requires us to save the original RA value, > > so here it saves RA at t0. > > details are: > > > > | Compiled | Disabled | Enabled | > > +------------+------------------------+------------------------+ > > | nop | move t0, ra | move t0, ra | > > | nop | nop | bl ftrace_caller | > > | func_body | func_body | func_body | > > > > The RA value will be recovered by ftrace_regs_entry, and restored into RA > > before returning to the regular function prologue. When a function is not > > being traced, the move t0, ra is not harmful. > > > > performs a series of startup tests on ftrace and The test cases in selftests > > has passed on LoongArch. > > > > Changes in v2: > > - Remove patch "LoongArch: ftrace: Add CALLER_ADDRx macros" there are other > > better ways > > Suggested by Steve: > > - Add HAVE_DYNAMIC_FTRACE_WITH_ARGS support (6/10) > > Suggested by Jinyang: > > - Change addu16id to lu12iw and Adjust module_finalize return value (7/10) > > - Use the "jr" pseudo-instruction where applicable (1/10) > > - Use the "la.pcrel" instead of "la" (3/10) > > > > Changes in v3: > > Reported by Jeff: > > - Fix unwind state when option func_stack_trace (10/10) > > > > Changes in v4: > > - No comments. Just resend the series. > > - Rebased onto v6.0.0-rc4. > > > > Changes in v5: > > - Modify the indentation of Kconfig and small changes > > > > Changes in v6: > > Suggested by Huacai: > > - Adjusting the patch Sequence > > - renamed mcount-dyn.S for consistency > > > > Changes in v7: > > - delete redefinition > > > > Changes in v8: > > - remove useless macro judgment and modify the return location > > - move some code to Patch-3 > > > > Qing Zhang (9): > > LoongArch/ftrace: Add basic support > > LoongArch/ftrace: Add recordmcount support > > LoongArch/ftrace: Add dynamic function tracer support > > LoongArch/ftrace: Add dynamic function graph tracer support > > LoongArch/ftrace: Add HAVE_DYNAMIC_FTRACE_WITH_REGS support > > LoongArch/ftrace: Add HAVE_DYNAMIC_FTRACE_WITH_ARGS support > > LoongArch/ftrace: Add HAVE_FUNCTION_GRAPH_RET_ADDR_PTR support > > LoongArch: modules/ftrace: Initialize PLT at load time > > LoongArch: Enable CONFIG_KALLSYMS_ALL and CONFIG_DEBUG_FS > > > > arch/loongarch/Kconfig | 7 + > > arch/loongarch/Makefile | 5 + > > arch/loongarch/configs/loongson3_defconfig | 2 + > > arch/loongarch/include/asm/ftrace.h | 59 +++++ > > arch/loongarch/include/asm/inst.h | 15 ++ > > arch/loongarch/include/asm/module.h | 5 +- > > arch/loongarch/include/asm/module.lds.h | 1 + > > arch/loongarch/include/asm/unwind.h | 3 +- > > arch/loongarch/kernel/Makefile | 13 + > > arch/loongarch/kernel/ftrace.c | 74 ++++++ > > arch/loongarch/kernel/ftrace_dyn.c | 264 +++++++++++++++++++++ > > arch/loongarch/kernel/inst.c | 127 ++++++++++ > > arch/loongarch/kernel/mcount.S | 94 ++++++++ > > arch/loongarch/kernel/mcount_dyn.S | 154 ++++++++++++ > > arch/loongarch/kernel/module-sections.c | 11 + > > arch/loongarch/kernel/module.c | 21 ++ > > arch/loongarch/kernel/unwind_guess.c | 4 +- > > arch/loongarch/kernel/unwind_prologue.c | 46 +++- > > scripts/recordmcount.c | 23 ++ > > 19 files changed, 918 insertions(+), 10 deletions(-) > > create mode 100644 arch/loongarch/include/asm/ftrace.h > > create mode 100644 arch/loongarch/kernel/ftrace.c > > create mode 100644 arch/loongarch/kernel/ftrace_dyn.c > > create mode 100644 arch/loongarch/kernel/mcount.S > > create mode 100644 arch/loongarch/kernel/mcount_dyn.S > > > > -- > > 2.36.0 > > > >
-- Thanks, JeffXie
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