TLB Miss Exception

As you can see from the .ptf (which is the real thing about sopc builder), the addresses were chosen to be at physical address in the lowest memory.

        
         reset_slave = "altmemddr_0/s1";
         break_slave = "cpu_0/jtag_debug_module";
         exc_slave = "altmemddr_0/s1";
         reset_offset = "0x00000020";
         break_offset = "0x00000020";
         exc_offset = "0x00000060";

You can find the ptf file in attachment

You can also find and image of the CPU configuration screen.

This is a custom design on a custom board. I have chosen to put the reset and exception vectors in these positions as a suggestion from the Altmemphy manual: on page 21 of emi_ddr_ug.pdf, I have found that the calibration process uses addresses between 0x0 and 0x1F. This can be avoided once I load my system from flash, because it is i a safe place at reset.

The DDR2 Controller I am using is based on Altmemphy and not Uniphy. So this is why I have chosen these addresses. Anyway I made a mistake, the addresses MUST be calculated multiplying the range for the bus dimension in bytes. On the other hand the kernel is not loading after a reset (it is downloaded via JTAG) so this should not be corrupted.

Anyway, the only constraint I remember about position is that they must be in the 0x0-0x1FFFFFFF memory range; obviously there must be enough space for the code and variables.

Then the sopc-create-header-files --single imcpu_fpga.h script generates the map translating all addresses in virtual memory. I am not sure that the point is in this translation, I have tracked a lot of system calls and other stuff (exceptions, interrupts or traps are considered exceptions as I know).

I have found that the instruction corresponding to the ea register is the stb instruction called from the macro put_user_asm, which is called from the macro __put_user_common, which is called from the macro __put_user which is called by the function __clear_user (arch/nios2/mm/uaccess.c).

I'll try to recompile with a different reset and break address. As you suggested.