[PATCH v4 1/4] soc: qcom: smem: add IN_PARTITION_RANGE helper

[Albert Esteve]

From: Sarannya S <sarannya.s@xxxxxxxxxxxxxxxx>

Add IN_PARTITION_RANGE() to test that a pointer lies in [start, end]
and that pointer + size does not wrap.

Signed-off-by: Sarannya S <sarannya.s@xxxxxxxxxxxxxxxx>
Signed-off-by: Pranav Mahesh Phansalkar <pranav.phansalkar@xxxxxxxxxxxxxxxx>
Signed-off-by: Sudeepgoud Patil <sudeep.patil@xxxxxxxxxxxxxxxx>
Signed-off-by: Albert Esteve <aesteve@xxxxxxxxxx>
---
 drivers/soc/qcom/smem.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/soc/qcom/smem.c b/drivers/soc/qcom/smem.c
index b5e7bd8c1512..36a4a10f3aec 100644
--- a/drivers/soc/qcom/smem.c
+++ b/drivers/soc/qcom/smem.c
@@ -2,6 +2,7 @@
 /*
  * Copyright (c) 2015, Sony Mobile Communications AB.
  * Copyright (c) 2012-2013, The Linux Foundation. All rights reserved.
+ * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
  */
 
 #include <linux/debugfs.h>
@@ -88,6 +89,18 @@
 /* Processor/host identifier for the global partition */
 #define SMEM_GLOBAL_HOST	0xfffe
 
+/* Entry range check
+ * ptr >= start : Checks if ptr is at or past the start of the region
+ * ptr <= end   : Checks if ptr is within the region
+ * size <= end - ptr: Checks if size fits in the remaining space, using
+ *                    uintptr_t subtraction to avoid pointer overflow UB
+ *                    (safe because ptr <= end is checked first)
+ */
+#define IN_PARTITION_RANGE(ptr, size, start, end)		\
+	((void *)(ptr) >= (void *)(start) &&			\
+	 (void *)(ptr) <= (void *)(end) &&			\
+	 (size) <= (uintptr_t)(end) - (uintptr_t)(ptr))
+
 /**
   * struct smem_proc_comm - proc_comm communication struct (legacy)
   * @command:	current command to be executed

-- 
2.55.0