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/nvram.c b/arch/powerpc/platforms/pseries/nvram.c
index cbf1720eb4aa..8130c37962c0 100644
--- a/arch/powerpc/platforms/pseries/nvram.c
+++ b/arch/powerpc/platforms/pseries/nvram.c
@@ -227,8 +227,8 @@ int __init pSeries_nvram_init(void)
 
 	nvram_size = be32_to_cpup(nbytes_p);
 
-	nvram_fetch = rtas_token("nvram-fetch");
-	nvram_store = rtas_token("nvram-store");
+	nvram_fetch = rtas_function_token(RTAS_FN_NVRAM_FETCH);
+	nvram_store = rtas_function_token(RTAS_FN_NVRAM_STORE);
 	printk(KERN_INFO "PPC64 nvram contains %d bytes\n", nvram_size);
 	of_node_put(nvram);