What is the use of .rwbarrier section?

[Sebastian Huber]

This section helps to protect the code and read-only sections from write access via the MMU. I would simply avoid generating bin files, they are next to useless. 

----- Am 27. Mai 2015 um 17:58 schrieb Ken Liao <ken.i18n at gmail.com>: 

> Dear all,
> I'm using Beaglebone BSP and the hello world example binary generated from 71600
> bytes .text section to 1055088 bytes
> after 'arm-rtems4.11-objcopy -S -O binary hello.exe hello.bin'.
> I assume the issue is cause by .rwbarrier section.

> arm-rtems4.11-readelf -e hello.ralf show:
> Section Headers:
> [Nr] Name Type Addr Off Size ES Flg Lk Inf Al
> [ 0] NULL 00000000 000000 000000 00 0 0 0
> [ 1] .start PROGBITS 80000000 000094 000384 00 AX 0 0 4
> [ 2] .text PROGBITS 80000384 000418 0108a0 00 WAX 0 0 4
> [ 3] .init PROGBITS 80010c24 010cb8 000018 00 AX 0 0 4
> [ 4] .fini PROGBITS 80010c3c 010cd0 000018 00 AX 0 0 4
> [ 5] .rodata PROGBITS 80010c54 010ce8 000b0c 00 A 0 0 4
> [ 6] .ARM.exidx ARM_EXIDX 80011760 0117f4 000008 00 AL 2 0 4
> [ 7] .eh_frame PROGBITS 80011768 0117fc 000048 00 A 0 0 4
> [ 8] .init_array INIT_ARRAY 800117b0 011844 000004 00 WA 0 0 4
> [ 9] .fini_array FINI_ARRAY 800117b4 011848 000004 00 WA 0 0 4
> [10] .jcr PROGBITS 800117b8 01184c 000004 00 WA 0 0 4
> [11] .rwbarrier NOBITS 800117bc 011850 0ee844 00 WA 0 0 1
> [12] .vector NOBITS 80100000 011850 001400 00 WA 0 0 1
> [13] .data PROGBITS 80101400 011860 000570 00 WA 0 0 8
> [14] .bss NOBITS 80101980 011dd0 001d90 00 WA 0 0 32
> [15] .work NOBITS 80103710 011dd0 fafc8f0 00 WA 0 0 1

> rtems/c/src/lib/libbsp/arm/beagle/startup/linkcmds.beagle:
> bsp_section_rwbarrier_align = DEFINED (bsp_section_rwbarrier_align) ?
> bsp_section_rwbarrier_align : 1M;

> rtems/c/src/lib/libbsp/arm/shared/startup/linkcmds.base:
> .rwbarrier : ALIGN_WITH_INPUT {
> . = ALIGN (bsp_section_rwbarrier_align);
> } > REGION_DATA AT > REGION_DATA

> So, what's the role of .rwbarrier section? Can i remove the section?

> Best regards,

> Ken Liao

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