powerpc/rtas: arch-wide function token lookup conversions

With the tokens for all implemented RTAS functions now available via
rtas_function_token(), which is optimal and safe for arbitrary
contexts, there is no need to use rtas_token() or cache its result.

Most conversions are trivial, but a few are worth describing in more
detail:

* Error injection token comparisons for lockdown purposes are
  consolidated into a simple predicate: token_is_restricted_errinjct().

* A couple of special cases in block_rtas_call() do not use
  rtas_token() but perform string comparisons against names in the
  function table. These are converted to compare against token values
  instead, which is logically equivalent but less expensive.

* The lookup for the ibm,os-term token can be deferred until needed,
  instead of caching it at boot to avoid device tree traversal during
  panic.

* Since rtas_function_token() accesses a read-only data structure
  without taking any locks, xmon's lookup of set-indicator can be
  performed as needed instead of cached at startup.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20230125-b4-powerpc-rtas-queue-v3-20-26929c8cce78@linux.ibm.com

1 files changed, 2 insertions, 2 deletions

diff --git a/arch/powerpc/platforms/pseries/rtas-work-area.c b/arch/powerpc/platforms/pseries/rtas-work-area.c
index 1ee63335bd4b..b37d52f40360 100644
--- a/arch/powerpc/platforms/pseries/rtas-work-area.c
+++ b/arch/powerpc/platforms/pseries/rtas-work-area.c
@@ -203,7 +203,7 @@ void __init rtas_work_area_reserve_arena(const phys_addr_t limit)
 	 * So set up the arena if we find that, with a fallback to
 	 * ibm,configure-connector, just in case.
 	 */
-	if (rtas_service_present("ibm,get-system-parameter") ||
-	    rtas_service_present("ibm,configure-connector"))
+	if (rtas_function_implemented(RTAS_FN_IBM_GET_SYSTEM_PARAMETER) ||
+	    rtas_function_implemented(RTAS_FN_IBM_CONFIGURE_CONNECTOR))
 		rwa_state.arena = memblock_alloc_try_nid(size, align, min, limit, nid);
 }