"Smallest shift of flexible pages" conflicts with the alignment of data section in link file.

[georgekang]

Memory fault would happen when the alignment of fpage is larger than data section.
In default setting, the fpage is 2^8-byte aligned and data section is at 0x20000400. Data section is not only 2^7-byte aligned but also 2^8-byte aligned. However, data section is only set as 2^7-byte aligned in link file. If data section is only 2^7-byte aligned(e.g. 0x2000480) and fpage is 2^8-byte aligned, memory fault would happen when accessing first 128 bytes of data section.

[jserv]

@southernbear Did you encounter alignment related issues as @georgekang described? In branch user-test, there are already some address spaces manipulation fixes.