[PATCH] powerpc: Fix STACKTRACE=n build

[Michael Ellerman]

On Sat, 12 Feb 2022 22:13:49 +1100, Michael Ellerman wrote:
> Our skiroot_defconfig doesn't enable FTRACE, and so doesn't get
> STACKTRACE enabled either. That leads to a build failure since commit
> 1614b2b11fab ("arch: Make ARCH_STACKWALK independent of STACKTRACE")
> made stacktrace.c build even when STACKTRACE=n.
> 
>   arch/powerpc/kernel/stacktrace.c: In function ‘handle_backtrace_ipi’:
>   arch/powerpc/kernel/stacktrace.c:171:2: error: implicit declaration of function ‘nmi_cpu_backtrace’
>     171 |  nmi_cpu_backtrace(regs);
>         |  ^~~~~~~~~~~~~~~~~
>   arch/powerpc/kernel/stacktrace.c: In function ‘arch_trigger_cpumask_backtrace’:
>   arch/powerpc/kernel/stacktrace.c:226:2: error: implicit declaration of function ‘nmi_trigger_cpumask_backtrace’
>     226 |  nmi_trigger_cpumask_backtrace(mask, exclude_self, raise_backtrace_ipi);
>         |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> [...]

Applied to powerpc/next.

[1/1] powerpc: Fix STACKTRACE=n build
      https://git.kernel.org/powerpc/c/5a72345e6a78120368fcc841b570331b6c5a50da

cheers