commit 4728f4fa305c98d1c53aac037599bdfbe0f65ed9
author Gatien Chapon <43855183+chapongatien@users.noreply.github.com> Mon Jun 17 19:22:53 2024 +0200
committer GitHub <noreply@github.com> Mon Jun 17 13:22:53 2024 -0400
tree 0eac753c60c927584d3fac4665bb21a1d7de46d4
parent a030a4750a11932a7957c1b7138b4076b96a535b

[NXP][platform] Forcing 4 bytes alignment for the RAM storage read buffer (#33895)

Issue could happen on NXP platforms supporting Matter with the RAM storage module + littlefs due to read buffer alignment issue.

As mflash_drv_read mandates the alignment of dst read buffer to 4 bytes, make sure to always align read buffers to 4 bytes.

Signed-off-by: Gatien Chapon <gatien.chapon@nxp.com>

src/platform/nxp/common/NXPConfig.cpp

diff --git a/src/platform/nxp/common/NXPConfig.cpp b/src/platform/nxp/common/NXPConfig.cpp
index cc6f8d5..b047d8a 100644
--- a/src/platform/nxp/common/NXPConfig.cpp
+++ b/src/platform/nxp/common/NXPConfig.cpp
@@ -84,14 +84,14 @@
 {
     uint16_t chipConfigRamBufferLen;
     uint16_t padding;
-    uint8_t chipConfigRamBuffer[CONFIG_CHIP_NVM_RAMBUFFER_SIZE_KEY_INT];
+    uint8_t chipConfigRamBuffer[CONFIG_CHIP_NVM_RAMBUFFER_SIZE_KEY_INT] __attribute__((aligned(4)));
 } ChipConfigRamStructKeyInt;
 
 typedef struct
 {
     uint16_t chipConfigRamBufferLen;
     uint16_t padding;
-    uint8_t chipConfigRamBuffer[CONFIG_CHIP_NVM_RAMBUFFER_SIZE_KEY_STRING];
+    uint8_t chipConfigRamBuffer[CONFIG_CHIP_NVM_RAMBUFFER_SIZE_KEY_STRING] __attribute__((aligned(4)));
 } ChipConfigRamStructKeyString;
 
 /* File system containing only integer keys */
@@ -193,6 +193,14 @@
 {
     if (!isInitialized)
     {
+        /*
+         * Make sure to check that read buffers are always 4 bytes aligned,
+         * as NXP flash drivers may mandate the alignment of dst read buffer to 4 bytes
+         */
+        static_assert(alignof(chipConfigRamStructKeyInt.chipConfigRamBuffer) == 4,
+                      "Wrong buffer alignment, it must be 4 bytes aligned");
+        static_assert(alignof(chipConfigRamStructKeyString.chipConfigRamBuffer) == 4,
+                      "Wrong buffer alignment, it must be 4 bytes aligned");
         ramStorageInit();
 
 #if (CHIP_PLAT_NVM_SUPPORT == CHIP_PLAT_NVM_FWK)