Messages in this thread Patch in this message | | | Subject | Re: [PATCH 1/6] LoongArch: Get frame info in unwind_start when regs is not supported | From | Qing Zhang <> | Date | Thu, 15 Dec 2022 13:24:47 +0800 |
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Hi, Jinyang
On 2022/12/15 下午12:01, Jinyang He wrote: > At unwind_start, it is better to try to get its frame info even we not > support regs rather than get them outside. So that we can simply use > unwind_{start, next_frame, done} outside. > > Signed-off-by: Jinyang He <hejinyang@loongson.cn> > --- > arch/loongarch/kernel/process.c | 12 +++--------- > arch/loongarch/kernel/unwind_guess.c | 6 ++++++ > arch/loongarch/kernel/unwind_prologue.c | 16 +++++++++++++--- > 3 files changed, 22 insertions(+), 12 deletions(-) > > diff --git a/arch/loongarch/kernel/process.c b/arch/loongarch/kernel/process.c > index 502b8b950057..6ef45174ad35 100644 > --- a/arch/loongarch/kernel/process.c > +++ b/arch/loongarch/kernel/process.c > @@ -197,20 +197,14 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) > > unsigned long __get_wchan(struct task_struct *task) > { > - unsigned long pc; > + unsigned long pc = 0; > struct unwind_state state; > > if (!try_get_task_stack(task)) > return 0; > > - unwind_start(&state, task, NULL); > - state.sp = thread_saved_fp(task); > - get_stack_info(state.sp, state.task, &state.stack_info); > - state.pc = thread_saved_ra(task); > -#ifdef CONFIG_UNWINDER_PROLOGUE > - state.type = UNWINDER_PROLOGUE; > -#endif > - for (; !unwind_done(&state); unwind_next_frame(&state)) { > + for (unwind_start(&state, task, NULL); !unwind_done(&state); > + unwind_next_frame(&state)) { > pc = unwind_get_return_address(&state); > if (!pc) > break; > diff --git a/arch/loongarch/kernel/unwind_guess.c b/arch/loongarch/kernel/unwind_guess.c > index e2d2e4f3001f..e03864511582 100644 > --- a/arch/loongarch/kernel/unwind_guess.c > +++ b/arch/loongarch/kernel/unwind_guess.c > @@ -26,6 +26,12 @@ void unwind_start(struct unwind_state *state, struct task_struct *task, > if (regs) { > state->sp = regs->regs[3]; > state->pc = regs->csr_era; > + } else if (task == current) { > + state->sp = (unsigned long)__builtin_frame_address(0); > + state->pc = (unsigned long)__builtin_return_address(0); > + } else { > + state->sp = thread_saved_fp(task); > + state->pc = thread_saved_ra(task); > The case for tasks is already handled in stacktrace.c, which is reusable code: void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie, struct task_struct *task, struct pt_regs *regs) { ...
if (task == current) { regs->regs[3] = (unsigned long)__builtin_frame_address(0); regs->csr_era = (unsigned long)__builtin_return_address(0); } else { regs->regs[3] = thread_saved_fp(task); regs->csr_era = thread_saved_ra(task); } ... for (unwind_start(&state, task, regs); !unwind_done(&state); unwind_next_frame(&state)) { addr = unwind_get_return_address(&state); ... }
> > state->task = task; > diff --git a/arch/loongarch/kernel/unwind_prologue.c b/arch/loongarch/kernel/unwind_prologue.c > index 0f8d1451ebb8..9d51ea37782e 100644 > --- a/arch/loongarch/kernel/unwind_prologue.c > +++ b/arch/loongarch/kernel/unwind_prologue.c > @@ -141,12 +141,22 @@ void unwind_start(struct unwind_state *state, struct task_struct *task, > struct pt_regs *regs) > { > memset(state, 0, sizeof(*state)); > + state->type = UNWINDER_PROLOGUE; > > - if (regs && __kernel_text_address(regs->csr_era)) { > - state->pc = regs->csr_era; > + if (regs) { > state->sp = regs->regs[3]; > + state->pc = regs->csr_era; > state->ra = regs->regs[1]; > - state->type = UNWINDER_PROLOGUE; > + if (!__kernel_text_address(state->pc)) > + state->type = UNWINDER_GUESS; > + } else if (task == current) { > + state->sp = (unsigned long)__builtin_frame_address(0); > + state->pc = (unsigned long)__builtin_return_address(0); > + state->ra = 0; > + } else { > + state->sp = thread_saved_fp(task); > + state->pc = thread_saved_ra(task); > + state->ra = 0; > } > also... > state->task = task; > Thanks, -Qing
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