[PATCH 1/8] arm64: stacktrace: simplify unwind_next_common()

[Kalesh Singh]

On Mon, Aug 1, 2022 at 5:12 AM Mark Rutland <mark.rutland at arm.com> wrote:
>
> Currently unwind_next_common() takes a pointer to a stack_info which is
> only ever used within unwind_next_common().
>
> Make it a local variable and simplify callers.
>
> There should be no functional change as a result of this patch.
>
> Signed-off-by: Mark Rutland <mark.rutland at arm.com>
> Cc: Fuad Tabba <tabba at google.com>
> Cc: Kalesh Singh <kaleshsingh at google.com>
> Cc: Madhavan T. Venkataraman <madvenka at linux.microsoft.com>
> Cc: Marc Zyngier <maz at kernel.org>
> Cc: Mark Brown <broonie at kernel.org>

Reviewed-by: Kalesh Singh <kaleshsingh at google.com>

> ---
>  arch/arm64/include/asm/stacktrace/common.h | 12 ++++++------
>  arch/arm64/kernel/stacktrace.c             |  3 +--
>  arch/arm64/kvm/hyp/nvhe/stacktrace.c       |  4 +---
>  arch/arm64/kvm/stacktrace.c                |  4 +---
>  4 files changed, 9 insertions(+), 14 deletions(-)
>
> diff --git a/arch/arm64/include/asm/stacktrace/common.h b/arch/arm64/include/asm/stacktrace/common.h
> index f58eb944c46fb..01dc9f44a24a7 100644
> --- a/arch/arm64/include/asm/stacktrace/common.h
> +++ b/arch/arm64/include/asm/stacktrace/common.h
> @@ -140,27 +140,27 @@ typedef bool (*on_accessible_stack_fn)(const struct task_struct *tsk,
>                                        struct stack_info *info);
>
>  static inline int unwind_next_common(struct unwind_state *state,
> -                                    struct stack_info *info,
>                                      on_accessible_stack_fn accessible,
>                                      stack_trace_translate_fp_fn translate_fp)
>  {
> +       struct stack_info info;
>         unsigned long fp = state->fp, kern_fp = fp;
>         struct task_struct *tsk = state->task;
>
>         if (fp & 0x7)
>                 return -EINVAL;
>
> -       if (!accessible(tsk, fp, 16, info))
> +       if (!accessible(tsk, fp, 16, &info))
>                 return -EINVAL;
>
> -       if (test_bit(info->type, state->stacks_done))
> +       if (test_bit(info.type, state->stacks_done))
>                 return -EINVAL;
>
>         /*
>          * If fp is not from the current address space perform the necessary
>          * translation before dereferencing it to get the next fp.
>          */
> -       if (translate_fp && !translate_fp(&kern_fp, info->type))
> +       if (translate_fp && !translate_fp(&kern_fp, info.type))
>                 return -EINVAL;
>
>         /*
> @@ -177,7 +177,7 @@ static inline int unwind_next_common(struct unwind_state *state,
>          * stack to another, it's never valid to unwind back to that first
>          * stack.
>          */
> -       if (info->type == state->prev_type) {
> +       if (info.type == state->prev_type) {
>                 if (fp <= state->prev_fp)
>                         return -EINVAL;
>         } else {
> @@ -191,7 +191,7 @@ static inline int unwind_next_common(struct unwind_state *state,
>         state->fp = READ_ONCE(*(unsigned long *)(kern_fp));
>         state->pc = READ_ONCE(*(unsigned long *)(kern_fp + 8));
>         state->prev_fp = fp;
> -       state->prev_type = info->type;
> +       state->prev_type = info.type;
>
>         return 0;
>  }
> diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
> index ce190ee18a201..056fb045d0e0c 100644
> --- a/arch/arm64/kernel/stacktrace.c
> +++ b/arch/arm64/kernel/stacktrace.c
> @@ -103,14 +103,13 @@ static int notrace unwind_next(struct unwind_state *state)
>  {
>         struct task_struct *tsk = state->task;
>         unsigned long fp = state->fp;
> -       struct stack_info info;
>         int err;
>
>         /* Final frame; nothing to unwind */
>         if (fp == (unsigned long)task_pt_regs(tsk)->stackframe)
>                 return -ENOENT;
>
> -       err = unwind_next_common(state, &info, on_accessible_stack, NULL);
> +       err = unwind_next_common(state, on_accessible_stack, NULL);
>         if (err)
>                 return err;
>
> diff --git a/arch/arm64/kvm/hyp/nvhe/stacktrace.c b/arch/arm64/kvm/hyp/nvhe/stacktrace.c
> index 58f645ad66bcb..50a1fa6b5c044 100644
> --- a/arch/arm64/kvm/hyp/nvhe/stacktrace.c
> +++ b/arch/arm64/kvm/hyp/nvhe/stacktrace.c
> @@ -71,9 +71,7 @@ static bool on_accessible_stack(const struct task_struct *tsk,
>
>  static int unwind_next(struct unwind_state *state)
>  {
> -       struct stack_info info;
> -
> -       return unwind_next_common(state, &info, on_accessible_stack, NULL);
> +       return unwind_next_common(state, on_accessible_stack, NULL);
>  }
>
>  static void notrace unwind(struct unwind_state *state,
> diff --git a/arch/arm64/kvm/stacktrace.c b/arch/arm64/kvm/stacktrace.c
> index 949d19d603fba..b9cf551d9d31d 100644
> --- a/arch/arm64/kvm/stacktrace.c
> +++ b/arch/arm64/kvm/stacktrace.c
> @@ -97,9 +97,7 @@ static bool on_accessible_stack(const struct task_struct *tsk,
>
>  static int unwind_next(struct unwind_state *state)
>  {
> -       struct stack_info info;
> -
> -       return unwind_next_common(state, &info, on_accessible_stack,
> +       return unwind_next_common(state, on_accessible_stack,
>                                   kvm_nvhe_stack_kern_va);
>  }
>
> --
> 2.30.2
>