[PATCH v4 07/13] powerpc/rtas: Warn if per-function lock isn't held
From: Nathan Lynch via B4 Relay <devnull+nathanl.linux.ibm.com@kernel.org>
Date: 2023-11-18 05:15:26
Also in:
b4-sent
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
From: Nathan Lynch <redacted> 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. Signed-off-by: Nathan Lynch <redacted> --- 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)
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2.41.0