lib: utils/irqchip: plic: Ensure no out-of-bound access in priority save/restore helpers

Currently the priority save/restore helpers writes/reads the provided
array using an index whose maximum value is determined by PLIC, which
potentially may disagree with the caller to these helpers.

Add a parameter to ask the caller to provide the size limit of the
array to ensure no out-of-bound access happens.

Signed-off-by: Bin Meng <bmeng@tinylab.org>
Reviewed-by: Anup Patel <anup@brainfault.org>

2 files changed, 15 insertions, 4 deletions

diff --git a/include/sbi_utils/irqchip/fdt_irqchip_plic.h b/include/sbi_utils/irqchip/fdt_irqchip_plic.h
index 98d4de5..d5b1c60 100644
--- a/include/sbi_utils/irqchip/fdt_irqchip_plic.h
+++ b/include/sbi_utils/irqchip/fdt_irqchip_plic.h
@@ -9,9 +9,19 @@
 
 #include <sbi/sbi_types.h>
 
-void fdt_plic_priority_save(u8 *priority);
+/**
+ * Save the PLIC priority state
+ * @param priority pointer to the memory region for the saved priority
+ * @param num size of the memory region including interrupt source 0
+ */
+void fdt_plic_priority_save(u8 *priority, u32 num);
 
-void fdt_plic_priority_restore(const u8 *priority);
+/**
+ * Restore the PLIC priority state
+ * @param priority pointer to the memory region for the saved priority
+ * @param num size of the memory region including interrupt source 0
+ */
+void fdt_plic_priority_restore(const u8 *priority, u32 num);
 
 void fdt_plic_context_save(bool smode, u32 *enable, u32 *threshold);
 
diff --git a/include/sbi_utils/irqchip/plic.h b/include/sbi_utils/irqchip/plic.h
index 48c24f0..38704a1 100644
--- a/include/sbi_utils/irqchip/plic.h
+++ b/include/sbi_utils/irqchip/plic.h
@@ -18,9 +18,10 @@ struct plic_data {
 };
 
 /* So far, priorities on all consumers of these functions fit in 8 bits. */
-void plic_priority_save(const struct plic_data *plic, u8 *priority);
+void plic_priority_save(const struct plic_data *plic, u8 *priority, u32 num);
 
-void plic_priority_restore(const struct plic_data *plic, const u8 *priority);
+void plic_priority_restore(const struct plic_data *plic, const u8 *priority,
+			   u32 num);
 
 void plic_context_save(const struct plic_data *plic, int context_id,
 		       u32 *enable, u32 *threshold);