| Message ID | 20231117-papr-sys_rtas-vs-lockdown-v4-7-b794d8cb8502@linux.ibm.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | powerpc/pseries: New character devices for system parameters and VPD | expand |
Nathan Lynch via B4 Relay <devnull+nathanl.linux.ibm.com@kernel.org> writes: > From: Nathan Lynch <nathanl@linux.ibm.com> > > If the function descriptor has a populated lock member, then callers > are required to hold it across calls. Now that the firmware activation > sequence is appropriately guarded, we can warn when the requirement > isn't satisfied. > > __do_enter_rtas_trace() gets reorganized a bit as a result of > performing the function descriptor lookup unconditionally now. > Reviewed-by: Aneesh Kumar K.V (IBM) <aneesh.kumar@kernel.org> > Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com> > --- > arch/powerpc/kernel/rtas.c | 21 +++++++++------------ > 1 file changed, 9 insertions(+), 12 deletions(-) > > diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c > index e38ba05ad613..deb6289fcf9c 100644 > --- a/arch/powerpc/kernel/rtas.c > +++ b/arch/powerpc/kernel/rtas.c > @@ -685,28 +685,25 @@ static void __do_enter_rtas(struct rtas_args *args) > > static void __do_enter_rtas_trace(struct rtas_args *args) > { > - const char *name = NULL; > + struct rtas_function *func = rtas_token_to_function(be32_to_cpu(args->token)); > > - if (args == &rtas_args) > - lockdep_assert_held(&rtas_lock); > /* > - * If the tracepoints that consume the function name aren't > - * active, avoid the lookup. > + * If there is a per-function lock, it must be held by the > + * caller. > */ > - if ((trace_rtas_input_enabled() || trace_rtas_output_enabled())) { > - const s32 token = be32_to_cpu(args->token); > - const struct rtas_function *func = rtas_token_to_function(token); > + if (func->lock) > + WARN_ON(!mutex_is_locked(func->lock)); > > - name = func->name; > - } > + if (args == &rtas_args) > + lockdep_assert_held(&rtas_lock); > > - trace_rtas_input(args, name); > + trace_rtas_input(args, func->name); > trace_rtas_ll_entry(args); > > __do_enter_rtas(args); > > trace_rtas_ll_exit(args); > - trace_rtas_output(args, name); > + trace_rtas_output(args, func->name); > } > > static void do_enter_rtas(struct rtas_args *args) > > -- > 2.41.0
diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c index e38ba05ad613..deb6289fcf9c 100644 --- a/arch/powerpc/kernel/rtas.c +++ b/arch/powerpc/kernel/rtas.c @@ -685,28 +685,25 @@ static void __do_enter_rtas(struct rtas_args *args) static void __do_enter_rtas_trace(struct rtas_args *args) { - const char *name = NULL; + struct rtas_function *func = rtas_token_to_function(be32_to_cpu(args->token)); - if (args == &rtas_args) - lockdep_assert_held(&rtas_lock); /* - * If the tracepoints that consume the function name aren't - * active, avoid the lookup. + * If there is a per-function lock, it must be held by the + * caller. */ - if ((trace_rtas_input_enabled() || trace_rtas_output_enabled())) { - const s32 token = be32_to_cpu(args->token); - const struct rtas_function *func = rtas_token_to_function(token); + if (func->lock) + WARN_ON(!mutex_is_locked(func->lock)); - name = func->name; - } + if (args == &rtas_args) + lockdep_assert_held(&rtas_lock); - trace_rtas_input(args, name); + trace_rtas_input(args, func->name); trace_rtas_ll_entry(args); __do_enter_rtas(args); trace_rtas_ll_exit(args); - trace_rtas_output(args, name); + trace_rtas_output(args, func->name); } static void do_enter_rtas(struct rtas_args *args)