Re: [PATCH] parisc: select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY

[Guenter Roeck]

On Wed, Feb 24, 2021 at 01:02:27PM -0800, Kees Cook wrote:
> On Wed, Feb 24, 2021 at 12:59:38PM -0800, Sami Tolvanen wrote:
> > parisc uses -fpatchable-function-entry with dynamic ftrace, which means we
> > don't need recordmcount. Select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
> > to tell that to the build system.
> > 
> > Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> > Fixes: 3b15cdc15956 ("tracing: move function tracer options to Kconfig")
> > Signed-off-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx>
> 
> I've got parisc building now, and can confirm:
> 
> Tested-by: Kees Cook <keescook@xxxxxxxxxxxx>
> 
> Guenter, does this fix it for you too?
> 

I get this:

WARNING: unmet direct dependencies detected for FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
  Depends on [n]: TRACING_SUPPORT [=y] && FTRACE [=y] && FTRACE_MCOUNT_RECORD [=n]
  Selected by [y]:
  - PARISC [=y] && HAVE_DYNAMIC_FTRACE [=y]

when trying to build parisc:defconfig.

I think it should be

	select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY if DYNAMIC_FTRACE

(no HAVE_)

Guenter

> -Kees
> 
> > ---
> >  arch/parisc/Kconfig | 1 +
> >  1 file changed, 1 insertion(+)
> > 
> > diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig
> > index ecef9aff9d72..9ee806f68123 100644
> > --- a/arch/parisc/Kconfig
> > +++ b/arch/parisc/Kconfig
> > @@ -60,6 +60,7 @@ config PARISC
> >  	select HAVE_KPROBES
> >  	select HAVE_KRETPROBES
> >  	select HAVE_DYNAMIC_FTRACE if $(cc-option,-fpatchable-function-entry=1,1)
> > +	select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY if HAVE_DYNAMIC_FTRACE
> >  	select HAVE_FTRACE_MCOUNT_RECORD if HAVE_DYNAMIC_FTRACE
> >  	select HAVE_KPROBES_ON_FTRACE
> >  	select HAVE_DYNAMIC_FTRACE_WITH_REGS
> > 
> > base-commit: 719bbd4a509f403f537adcaefd8ce17532be2e84
> > -- 
> > 2.30.0.617.g56c4b15f3c-goog
> > 
> 
> -- 
> Kees Cook