What does the "Access" attribute mean in the bit [0] of the MEMATTRS signal from the CortexM4 IP and how do I assert the same

Question

I wanted to know how to set the allocate bit (bit[0]) of the MEMATTRS signal (of the system bus) in the cortex m4 IP. What do I configure to get the bit to toggle? Also, I couldn't find any description in the cortex m4 manual talking about the allocate attribute and how to set it. I saw that there are ways to change shareability using the MPU feature, but nothing on the allocate attribute. Could someone help me understand what the allocate attribute is and point to any documentation which speaks about changing it.