Re: [PATCH 5/6] target/arm: Share ARM_PSCI_CALL trace event between TCG and HVF

[Peter Maydell <peter.maydell@linaro.org>]

On Mon, 30 Jun 2025 at 17:53, Pierrick Bouvier
<pierrick.bouvier@linaro.org> wrote:
>
> On 6/30/25 6:09 AM, Philippe Mathieu-Daudé wrote:
> > It is useful to compare PSCI calls of the same guest running
> > under TCG or HVF.
> >
> > Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> > ---
> >   target/arm/hvf/hvf.c    | 3 ++-
> >   target/arm/tcg/psci.c   | 3 +++
> >   target/arm/trace-events | 3 +++
> >   3 files changed, 8 insertions(+), 1 deletion(-)
> >
> > diff --git a/target/arm/hvf/hvf.c b/target/arm/hvf/hvf.c
> > index 7a99118c8c2..6309c5b872e 100644
> > --- a/target/arm/hvf/hvf.c
> > +++ b/target/arm/hvf/hvf.c
> > @@ -34,6 +34,7 @@
> >   #include "target/arm/multiprocessing.h"
> >   #include "target/arm/gtimer.h"
> >   #include "trace.h"
> > +#include "../trace.h"


> Just a nit, using 'target/arm/trace.h' might be more readable than
> '../trace.h'.

Mmm. docs/devel/tracing.rst rather discourages this:

# While it is possible to include a trace.h file from outside a source
file's own
# sub-directory, this is discouraged in general. It is strongly preferred that
# all events be declared directly in the sub-directory that uses them. The only
# exception is where there are some shared trace events defined in the top level
# directory trace-events file.

I don't know if we want to loosen that to permit events
that are shared between multiple subdirs (cc'ing the
trace subsystem maintainers for their view).

git grep 'include.*trace.h' | grep -v '"trace.h"'| grep -v 'trace.h:'|less

suggests that the only current place where we're including
a trace.h not in the same directory is linux-user, where
we opt to use the full linux-user/trace.h path. So probably
for consistency we should use target/arm/trace.h here.

(That grep also shows up that hw/uefi is missing its
trace.h header and the .c files are including
trace-hw_uefi.h directly...)

-- PMM