Hello @Ganesh_Pawar,
The S32K342 part has
- 64KB of SRAM
- 64KB of ITCM
- 128KB of DTCM
S32K3xx_memory_map.xlsx

And the linker file already uses the whole SRAM (64KB)

The default linker file is just an example, it can be modified as needed,
Regards,
Daniel