PSCI: fix limit of 256 CPUs caused by cast to unsigned char

In psci_setup.c psci_init_pwr_domain_node() takes an unsigned
char as node_idx which limits it to initialising only the first
256 CPUs. As the calling function does not check for a limit of
256 I think this is a bug so change the unsigned char to
uint16_t and change the cast from the calling site in
populate_power_domain_tree().

Also update the non_cpu_pwr_domain_node structure lock_index
to uint16_t and update the function signature for psci_lock_init()
appropriately.

Finally add a define PSCI_MAX_CPUS_INDEX to psci_private.h and add
a CASSERT to psci_setup.c to make sure PLATFORM_CORE_COUNT cannot
exceed the index value.

Signed-off-by: Graeme Gregory <graeme@nuviainc.com>
Change-Id: I9e26842277db7483fd698b46bbac62aa86e71b45

1 files changed, 7 insertions, 2 deletions

diff --git a/lib/psci/psci_private.h b/lib/psci/psci_private.h
index e2dcfa8b1..72bd6bd11 100644
--- a/lib/psci/psci_private.h
+++ b/lib/psci/psci_private.h
@@ -42,6 +42,11 @@
 			define_psci_cap(PSCI_SYSTEM_RESET2_AARCH64) |	\
 			define_psci_cap(PSCI_MEM_CHK_RANGE_AARCH64))
 
+/* Internally PSCI uses a uint16_t for various cpu indexes so
+ * define a limit to number of CPUs that can be initialised.
+ */
+#define PSCI_MAX_CPUS_INDEX	0xFFFFU
+
 /*
  * Helper functions to get/set the fields of PSCI per-cpu data.
  */
@@ -134,7 +139,7 @@ typedef struct non_cpu_pwr_domain_node {
 	unsigned char level;
 
 	/* For indexing the psci_lock array*/
-	unsigned char lock_index;
+	uint16_t lock_index;
 } non_cpu_pd_node_t;
 
 typedef struct cpu_pwr_domain_node {
@@ -239,7 +244,7 @@ static inline void psci_lock_release(non_cpu_pd_node_t *non_cpu_pd_node)
 #endif /* HW_ASSISTED_COHERENCY */
 
 static inline void psci_lock_init(non_cpu_pd_node_t *non_cpu_pd_node,
-				  unsigned char idx)
+				  uint16_t idx)
 {
 	non_cpu_pd_node[idx].lock_index = idx;
 }