diff options
| author | Nathan Lynch <nathanl@linux.ibm.com> | 2023-12-12 20:01:55 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2023-12-13 13:38:21 +0300 |
| commit | e3681107bc9f97c5948a1c8a3a97ac64907210ce (patch) | |
| tree | d1ea8fafb2b6f73f1c16bac0e44b082f29db7a66 /arch/powerpc/kernel | |
| parent | dc7637c402b90a197d3f21a3d78f2b00b67ea22a (diff) | |
| download | linux-e3681107bc9f97c5948a1c8a3a97ac64907210ce.tar.xz | |
powerpc/rtas: Warn if per-function lock isn't held
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>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231212-papr-sys_rtas-vs-lockdown-v6-8-e9eafd0c8c6c@linux.ibm.com
Diffstat (limited to 'arch/powerpc/kernel')
| -rw-r--r-- | arch/powerpc/kernel/rtas.c | 21 |
1 files changed, 9 insertions, 12 deletions
diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c index 72f6b5a402dd..7e793b503e29 100644 --- a/arch/powerpc/kernel/rtas.c +++ b/arch/powerpc/kernel/rtas.c @@ -671,28 +671,25 @@ static void __do_enter_rtas(struct rtas_args *args) static void __do_enter_rtas_trace(struct rtas_args *args) { - const char *name = NULL; + const 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) + lockdep_assert_held(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) |