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Cortex A9 MMU

deas

Hello,

I run a baremetal program  on one core of the Cortex A9. The First Stage Bootloader (FSBL, Pre-Loader) and the Second Stage Bootloader (SSBL) perform perfectly. When the baremetal application (axf-file) is started in the debugger it executes without a problem. However when the baremetal application (bin-file) is exectued directly on the machine, the baremetal application cannot be started and the follwing error is thrown:

data abort

MAYBE you should read doc/README.arm-unligned-accesses

However, when the MMU is deactivated, the application (bin-file and axf-file) execute perfectly.

This leads me to the follwing questions:

Why can the program be started in the Debugger, and at the same time cause a data abort, when the binary is executed on the machine?

Why could the MMU cause a data abort, when the bin-file is started on the machine?

I would be grateful for any hints and tips. Many thanks in advance.

Deas

Parents
  • 0 in reply to 42Bastian Schick

    Hello Bastian,

    I wrote a scatter file, for these declarations:

    SDRAM 0x100000 0x03F00000
{
    VECTORS +0
    {
        *(VECTORS, +FIRST)
    }
    APP_CODE +0
    {
        *(+RO, +RW, +ZI)
    }
    ARM_LIB_STACKHEAP +0 EMPTY (0x3F000000 - ImageLimit(APP_CODE)) ; Application Heap and Stack
    {}
}

    The entry point of the application.bin is 0x00100000, which I checked with the command readelf -h application.axf. 

    Thanks for your support.

    Deas

Reply
  • 0 in reply to 42Bastian Schick

    Hello Bastian,

    I wrote a scatter file, for these declarations:

    SDRAM 0x100000 0x03F00000
{
    VECTORS +0
    {
        *(VECTORS, +FIRST)
    }
    APP_CODE +0
    {
        *(+RO, +RW, +ZI)
    }
    ARM_LIB_STACKHEAP +0 EMPTY (0x3F000000 - ImageLimit(APP_CODE)) ; Application Heap and Stack
    {}
}

    The entry point of the application.bin is 0x00100000, which I checked with the command readelf -h application.axf. 

    Thanks for your support.

    Deas

Children
  • 0 in reply to deas

    I take the liberty to just post the information about the elf-file.

    readelf -h application.axf
ELF Header:
   Magic:   7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
   Class:                             ELF32
   Data:                              2's complement, little endian
   Version:                           1 (current)
   OS/ABI:                            UNIX - System V
   ABI Version:                       0
   Type:                              EXEC (Executable file)
   Machine:                           ARM
   Version:                           0x1
   Entry point address:               0x100000
   Start of program headers:          381792 (bytes into file)
   Start of section headers:          381824 (bytes into file)
   Flags:                             0x5000402, Version5 EABI, 
hard-float ABI, <unknown>
   Size of this header:               52 (bytes)
   Size of program headers:           32 (bytes)
   Number of program headers:         1
   Size of section headers:           40 (bytes)
   Number of section headers:         18
   Section header string table index: 17