ERROR 65 USING REMAP FEATURE ON ARM

Answer

Information in this article applies to:

uVision3 any Version
ARM Development Tools

QUESTION

I am using the uVision Simulator on an STR7xx device. When I start the simulator, I have the following memory map:

MAP
0x00000000 - 0x0003FFFF exec read
0x20000000 - 0x2000FFFF read write
  :            :

During run-time, I copy program code into the RAM and use the PCU_BOOTCR register to remap the RAM on the fly to address space 0 using the instruction:

  PCU->BOOTCR |= 2

Everything works just fine, however the memory map for address region is now:

MAP
0x00000000 - 0x0000FFFF read write        // this should be executable!!
0x20000000 - 0x2000FFFF read write
  :            :

When there is an interrupt in my program, the simulator reacts correctly with:

*** error 65: access violation at 0x00000008 : no 'execute/read' permission

This is the correct behavior according to the memory map, but prevents correct code execution. Is there a solution to my problem?

ANSWER

When you REMAP the RAM to the memory region 0, the mapping attributes are taken from the original RAM region. Change the mapping for the RAM region using the MAP command as shown below:

MAP 0x20000000, 0x2000003F read write exec

This also changes the mapping for region 0 once you have remapped the RAM.

MORE INFORMATION

Article last edited on: 2007-01-11 09:05:40

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