Why the stack size is fixed?

Dear All:

           I am using F28035 and CCS 6.2 to build my project.

In the .map file, the stack is always 0x200:

                   .stack 1 00000400 00000200 UNINITIALIZED
                                  00000400 00000200 --HOLE--

                   1 00000400 __stack
                   1 00000600 __STACK_END

But my build option is --stack_size=0x380 .

No matter what I set in the build option,  the stack is always 0x200 in the map file. Why ?