TMDXIDK5718: RTOS load and run placement of .data section

Markus Mueller

Part Number: TMDXIDK5718
Other Parts Discussed in Thread: SYSBIOS

I'm using CCS7.3 with SYSBIOS V6.46.5.55 and GNU Compiler V6.3.1 to build an application for the A15 processor on IDK5718.

Accroding to

processors.wiki.ti.com/.../BIOS_with_GCC_(CortexA)

I tried to put the .data section into different memory segments for load und run time.
So I added the following to my config script:

Program.sectMap[".data"] = new Program.SectionSpec();
Program.sectMap[".data"].loadSegment = "DATA_INIT";
Program.sectMap[".data"].runSegment = "EXT_RAM";

DATA_INIT and EXT_RAM are defined by my own platform file.

In the automatically created linker command file (..\Debug\configPkg\linker.cmd) I can see that the memory segments are correctly defined (only relevant parts displayed):

MEMORY
{
EXT_RAM (RWX) : org = 0x84000000, len = 0x3c000000
DATA_INIT (RW) : org = 0x82000000, len = 0x2000000
}

In the same linker command file the .data section is defined as:

.data : {*(.data)} > EXT_RAM AT> DATA_INIT

...

.data : {
        __data_load__ = LOADADDR (.data);
        __data_start__ = .;
        *(.got.plt)
        *(.got)
        *(.shdata)
        KEEP (*(.data))
        KEEP (*(.data*))
        *(.gnu.linkonce.d.*)
        . = ALIGN (4);
        __data_end__ = .;
} > REGION_DATA AT> REGION_TEXT

When I have a look at the created map file only the run address of the .data section is used (0x84000000 within EXT_RAM).
The load address is not used at all (__data_load__ sould be 0x82000000).

0x84000000 __data_load__ = LOADADDR (.data)
0x84000000 __data_start__ = .

How can I tell the linker to place the load adress of the .data section to a different address than the run address?

Regards,
Markus

over 8 years ago

0 Biser Gatchev-XID over 8 years ago

TI__Guru**** 393215 points

The RTOS team have been notified. They will respond here.

0 Markus Mueller over 8 years ago in reply to Biser Gatchev-XID

Expert 1370 points

Any update on this issue?

Regards,
Markus

0 lding over 8 years ago in reply to Markus Mueller

TI__Guru* 95265 points

Hi,

Sorry, I missed this thread. In our Processor SDK RTOS driver example, we have similar case for VPS loopback. In the configuration file:

Program.sectMap[".bss:frameBuffer"].loadSegment = "APP_CACHED_DATA_BLK1_MEM";

In the map file:

APP_CACHED_DATA_BLK1_MEM 0x80c00000 0x0f400000

.bss:frameBuffer
                0x80c00000 0xf400000
*(.bss:frameBuffer)
.bss:frameBuffer
                0x80c00000 0xf400000 C:\ti\pdk_am57xx_1_0_4\packages\ti\drv\vps\lib\am572x\a15\release\vps_examples_utility.aa15fg(bsputils_mem_default.oa15fg)
                0x80c00000                gBspUtils_heapMemFrame

So, I don't see a problem if you define a loadSegment and put data there.

Regards, Eric

0 Markus Mueller over 8 years ago in reply to lding

Expert 1370 points

Hi Eric

As it stil did not work I made some experiments.
Then I found out that it perfectly works with sections which I defined on my own.
e.g.:

__attribute__((section(".mysection")))
void TestFunction(void) {}

Program.sectMap[".mysection"] = new Program.SectionSpec();
Program.sectMap[".mysection"].loadSegment = "DATA_LOAD";
Program.sectMap[".mysection"].runSegment = "DATA_TUN";

Everything I put in that section occurs in the right place in the map file.

But when I try to put build-in sections (like .text, .data, .bss, ...) to a different place it is completely ignored.
Any ideas?

Regards,
Markus

Processors

Processors forum

TMDXIDK5718: RTOS load and run placement of .data section