[PATCH 6/8] arm64: stacktrace: remove stack type from fp translator

[Kalesh Singh]

On Mon, Aug 1, 2022 at 5:12 AM Mark Rutland <mark.rutland at arm.com> wrote:
>
> In subsequent patches we'll remove the stack_type enum, and move the FP
> translation logic out of the raw FP unwind code.
>
> In preparation for doing so, this patch removes the type parameter from
> the FP translation callback, and modifies kvm_nvhe_stack_kern_va() to
> determine the relevant stack directly.
>
> So that kvm_nvhe_stack_kern_va() can use the stackinfo_*() helpers,
> these are moved earlier in the file, but are not modified in any way.
>
> 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 |  6 +-
>  arch/arm64/kvm/stacktrace.c                | 78 ++++++++++++----------
>  2 files changed, 43 insertions(+), 41 deletions(-)
>
> diff --git a/arch/arm64/include/asm/stacktrace/common.h b/arch/arm64/include/asm/stacktrace/common.h
> index 0071f2459c703..0bd9d7ad295e0 100644
> --- a/arch/arm64/include/asm/stacktrace/common.h
> +++ b/arch/arm64/include/asm/stacktrace/common.h
> @@ -114,13 +114,11 @@ static inline void unwind_init_common(struct unwind_state *state,
>   * a kernel address.
>   *
>   * @fp:   the frame pointer to be updated to its kernel address.
> - * @type: the stack type associated with frame pointer @fp
>   *
>   * Returns true and success and @fp is updated to the corresponding
>   * kernel virtual address; otherwise returns false.
>   */
> -typedef bool (*stack_trace_translate_fp_fn)(unsigned long *fp,
> -                                           enum stack_type type);
> +typedef bool (*stack_trace_translate_fp_fn)(unsigned long *fp);
>
>  /*
>   * on_accessible_stack_fn() - Check whether a stack range is on any
> @@ -165,7 +163,7 @@ unwind_next_frame_record(struct unwind_state *state,
>          * 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))
>                 return -EINVAL;
>
>         /*
> diff --git a/arch/arm64/kvm/stacktrace.c b/arch/arm64/kvm/stacktrace.c
> index 3b005530ac02a..62ffa2b40da10 100644
> --- a/arch/arm64/kvm/stacktrace.c
> +++ b/arch/arm64/kvm/stacktrace.c
> @@ -21,6 +21,34 @@
>
>  #include <asm/stacktrace/nvhe.h>
>
> +static struct stack_info stackinfo_get_overflow(void)
> +{
> +       struct kvm_nvhe_stacktrace_info *stacktrace_info
> +                               = this_cpu_ptr_nvhe_sym(kvm_stacktrace_info);
> +       unsigned long low = (unsigned long)stacktrace_info->overflow_stack_base;
> +       unsigned long high = low + OVERFLOW_STACK_SIZE;
> +
> +       return (struct stack_info) {
> +               .low = low,
> +               .high = high,
> +               .type = STACK_TYPE_OVERFLOW,
> +       };
> +}
> +
> +static struct stack_info stackinfo_get_hyp(void)
> +{
> +       struct kvm_nvhe_stacktrace_info *stacktrace_info
> +                               = this_cpu_ptr_nvhe_sym(kvm_stacktrace_info);
> +       unsigned long low = (unsigned long)stacktrace_info->stack_base;
> +       unsigned long high = low + PAGE_SIZE;
> +
> +       return (struct stack_info) {
> +               .low = low,
> +               .high = high,
> +               .type = STACK_TYPE_HYP,
> +       };
> +}
> +
>  /*
>   * kvm_nvhe_stack_kern_va - Convert KVM nVHE HYP stack addresses to a kernel VAs
>   *
> @@ -34,27 +62,31 @@
>   * Returns true on success and updates @addr to its corresponding kernel VA;
>   * otherwise returns false.
>   */
> -static bool kvm_nvhe_stack_kern_va(unsigned long *addr,
> -                                  enum stack_type type)
> +static bool kvm_nvhe_stack_kern_va(unsigned long *addr)
>  {
>         struct kvm_nvhe_stacktrace_info *stacktrace_info;
>         unsigned long hyp_base, kern_base, hyp_offset;
> +       struct stack_info stack;
>
>         stacktrace_info = this_cpu_ptr_nvhe_sym(kvm_stacktrace_info);
>
> -       switch (type) {
> -       case STACK_TYPE_HYP:
> +       stack = stackinfo_get_hyp();
> +       if (stackinfo_on_stack(&stack, *addr, 1)) {
>                 kern_base = (unsigned long)*this_cpu_ptr(&kvm_arm_hyp_stack_page);
>                 hyp_base = (unsigned long)stacktrace_info->stack_base;
> -               break;
> -       case STACK_TYPE_OVERFLOW:
> +               goto found;
> +       }
> +
> +       stack = stackinfo_get_overflow();
> +       if (stackinfo_on_stack(&stack, *addr, 1)) {
>                 kern_base = (unsigned long)this_cpu_ptr_nvhe_sym(overflow_stack);
>                 hyp_base = (unsigned long)stacktrace_info->overflow_stack_base;
> -               break;
> -       default:
> -               return false;
> +               goto found;
>         }
>
> +       return false;
> +
> +found:
>         hyp_offset = *addr - hyp_base;
>
>         *addr = kern_base + hyp_offset;
> @@ -62,34 +94,6 @@ static bool kvm_nvhe_stack_kern_va(unsigned long *addr,
>         return true;
>  }
>
> -static struct stack_info stackinfo_get_overflow(void)
> -{
> -       struct kvm_nvhe_stacktrace_info *stacktrace_info
> -                               = this_cpu_ptr_nvhe_sym(kvm_stacktrace_info);
> -       unsigned long low = (unsigned long)stacktrace_info->overflow_stack_base;
> -       unsigned long high = low + OVERFLOW_STACK_SIZE;
> -
> -       return (struct stack_info) {
> -               .low = low,
> -               .high = high,
> -               .type = STACK_TYPE_OVERFLOW,
> -       };
> -}
> -
> -static struct stack_info stackinfo_get_hyp(void)
> -{
> -       struct kvm_nvhe_stacktrace_info *stacktrace_info
> -                               = this_cpu_ptr_nvhe_sym(kvm_stacktrace_info);
> -       unsigned long low = (unsigned long)stacktrace_info->stack_base;
> -       unsigned long high = low + PAGE_SIZE;
> -
> -       return (struct stack_info) {
> -               .low = low,
> -               .high = high,
> -               .type = STACK_TYPE_HYP,
> -       };
> -}
> -
>  static bool on_accessible_stack(const struct task_struct *tsk,
>                                 unsigned long sp, unsigned long size,
>                                 struct stack_info *info)
> --
> 2.30.2
>