Yeah until you or someone can figure out how to get the .ARM.exidx section from being placed in the .bss, a quick work-around would be to provide an alternate code to clear the bss that does something like...
memset(bsp_section_bss_begin, 0, __exidx_start - bsp_section_bss_begin); memset(__exidx_start, 0, bsp_section_bss_end); On Tue, Aug 11, 2015 at 9:32 AM, Rohini Kulkarni <krohini1...@gmail.com> wrote: > OK! So is there any immediate solution which can be tried? > > On Tue, Aug 11, 2015 at 6:32 PM, Gedare Bloom <ged...@gwu.edu> wrote: >> >> I can see the following pertinent information: >> [15] .bss NOBITS 001156e0 0a8fd8 00fab0 00 WA 0 >> 0 32 >> The bss section starts at 0x1156e0, has size 0xfab0, and is writeable. >> >> In the symbol table we can see: >> >> 7825: 001156e0 0 NOTYPE GLOBAL DEFAULT 15 bsp_section_bss_begin >> The bsp_section_bss_begin variable has value 0x1156e0, this is good. >> >> 8729: 0000fab0 0 NOTYPE GLOBAL DEFAULT ABS bsp_section_bss_size >> The bsp_section_bss_size is 0xfab0, which is also good. >> >> Looking at the segments I see one possible oddity. Look at the first and >> last >> Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align >> EXIDX 0x0a3fb8 0x001106b8 0x001106b8 0x00008 0x00008 R 0x4 >> LOAD 0x093900 0x00100000 0x00100000 0x156d8 0x7efc000 RW 0x20 >> >> The first one starts inside of the second! This could well be the >> reason for your problem. The .ARM.exidx section is being define >> read-only, and is being put into a segment that overlaps with the >> segment that catches most of the RW memory. >> >> Gedare >> >> On Mon, Aug 10, 2015 at 4:23 PM, Rohini Kulkarni <krohini1...@gmail.com> >> wrote: >> > I did a readelf on the rki elf. I have attached the file. Is this >> > information helping in anyway? >> > >> > On Wed, Aug 5, 2015 at 9:16 PM, Gedare Bloom <ged...@gwu.edu> wrote: >> >> >> >> In arm/shared/startup/linkcmds.base these barriers are used to add >> >> gaps in the memory layout at link-time to accommodate for the size >> >> requirements of the MMU. xbarrier aligns the executable region, >> >> robarrier aligns the read-only memory, and rwbarrier aligns the >> >> read-write memory. >> >> >> >> On Tue, Aug 4, 2015 at 6:23 PM, Rohini Kulkarni <krohini1...@gmail.com> >> >> wrote: >> >> > >> >> > >> >> > On Wed, Aug 5, 2015 at 1:47 AM, Gedare Bloom <ged...@gwu.edu> wrote: >> >> >> >> >> >> On Tue, Aug 4, 2015 at 2:18 PM, Rohini Kulkarni >> >> >> <krohini1...@gmail.com> >> >> >> wrote: >> >> >> > >> >> >> > >> >> >> > On Tue, Jul 28, 2015 at 5:51 AM, Pavel Pisa >> >> >> > <ppisa4li...@pikron.com> >> >> >> > wrote: >> >> >> >> >> >> >> >> Hello Rohini and Gedare, >> >> >> >> >> >> >> >> On Friday 24 of July 2015 15:33:03 Gedare Bloom wrote: >> >> >> >> > What are the values of bsp_section_bss_begin, and >> >> >> >> > bsp_section_bss_size? >> >> >> >> > >> >> >> >> > Apparently, the memset is trying to write into the .text (code) >> >> >> >> > section, which is a very bad thing to do indeed. >> >> >> >> > >> >> >> >> >> >> >> >> Qiao Yang in RPi 1 BSP now works in the similar >> >> >> >> area to enable right graphic memory mapping. >> >> >> >> >> >> >> >> So my guess is that there could be problem caused >> >> >> >> by used MMU mode granularity, which is is 1 MB so >> >> >> >> if RO and RW sections are present in the same 1MB >> >> >> >> aligned block ten there can be problem. It depends >> >> >> >> which section is filled the first. If data and then >> >> >> >> text (RO) the troubles begin. If the order is vice >> >> >> >> versa then some part of text can be RW instead of RO, >> >> >> >> but it should work and cache should not be a problem. >> >> >> >> >> >> >> >> But I have not dig into this case too much. >> >> >> >> Only short glimpse. >> >> >> >> >> >> >> >> One option is to define 1 MB alignment between text >> >> >> >> ad data for RPi case. There is quite a lot of memory >> >> >> >> when compared to most RTEMS embedded targets to the >> >> >> >> waste is not so important. >> >> >> > >> >> >> > >> >> >> > I didn't quite get what this means. I have no clue on how to >> >> >> > proceed >> >> >> > with >> >> >> > this. >> >> >> The MMU defines memory regions in 1MB chunks. Each chunk can have >> >> >> its >> >> >> own permissions (read-only, or read-write) set. If the .text and >> >> >> .data >> >> >> (or some other section) overlaps in the same 1MB chunk, and the >> >> >> wrong >> >> >> permission gets set, then there can be a problem e.g. part of .data >> >> >> might be RO or part of .text might be RW. >> >> >> >> >> >> Did you try the code Sebastian posted? to change the robarrier to >> >> >> rwbarrier? >> >> > >> >> > >> >> > What exactly are these barriers? >> >> >> >> >> >> >> >> >> Gedare >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> Best wishes, >> >> >> >> >> >> >> >> Pavel >> >> >> >> >> >> >> >> On Friday 24 of July 2015 21:55:00 Rohini Kulkarni wrote: >> >> >> >> > Hi, >> >> >> >> > >> >> >> >> > I have attached the report containing outputs of >> >> >> >> > arm-rtems4.11-size >> >> >> >> > and >> >> >> >> > arm-rtems4.11-nm -S. >> >> >> >> > >> >> >> >> > From arm-rtems4.11-nm -S I don't see how memset() is accessing >> >> >> >> > .text >> >> >> >> > section. The start and end values for both are not overlapping. >> >> >> >> > >> >> >> >> > On Fri, Jul 24, 2015 at 7:03 PM, Gedare Bloom <ged...@gwu.edu> >> >> >> >> > wrote: >> >> >> >> > > On Fri, Jul 24, 2015 at 3:30 AM, Rohini Kulkarni >> >> >> >> > > <krohini1...@gmail.com> >> >> >> >> > > >> >> >> >> > > wrote: >> >> >> >> > > > On 24 Jul 2015 12:35, "Sebastian Huber" < >> >> >> >> > > >> >> >> >> > > sebastian.hu...@embedded-brains.de> >> >> >> >> > > >> >> >> >> > > > wrote: >> >> >> >> > > >> On 23/07/15 23:24, Rohini Kulkarni wrote: >> >> >> >> > > >>> I could finally get back to this issue. I used Pi 1 for >> >> >> >> > > >>> debugging, >> >> >> >> > > >>> but the reason for this problem will apply to Pi 2 also. >> >> >> >> > > >>> With text section set to ARMV7_MMU_CODE_CACHED ( which >> >> >> >> > > >>> implies >> >> >> >> > > >>> read >> >> >> >> > > >> >> >> >> > > only) >> >> >> >> > > >> >> >> >> > > >>> , a data abort exception occurs with memset() inside >> >> >> >> > > >> >> >> >> > > bsp_start_clear_bss() >> >> >> >> > > >> >> >> >> > > >>> function. An illegal write access to an address according >> >> >> >> > > >>> to >> >> >> >> > > >>> me. >> >> >> >> > > >> >> >> >> >> > > >> Which exception and which address? Something is not >> >> >> >> > > >> working >> >> >> >> > > >> here. >> >> >> >> > > > >> >> >> >> > > > This is a part of the debugging output. When I used >> >> >> >> > > >> >> >> >> > > ARMV7_MMU_CODE_CACHED. >> >> >> >> > > >> >> >> >> > > > (gdb) s >> >> >> >> > > > bsp_start_clear_bss () >> >> >> >> > > > at >> >> >> >> > > > ../../../../../.././raspberrypi/lib/include/bsp/start.h:126 >> >> >> >> > > > 126 memset(bsp_section_bss_begin, 0, (size_t) >> >> >> >> > > > bsp_section_bss_size); >> >> >> >> > > >> >> >> >> > > What are the values of bsp_section_bss_begin, and >> >> >> >> > > bsp_section_bss_size? >> >> >> >> > > >> >> >> >> > > Apparently, the memset is trying to write into the .text >> >> >> >> > > (code) >> >> >> >> > > section, which is a very bad thing to do indeed. >> >> >> >> > > >> >> >> >> > > > (gdb) s >> >> >> >> > > > memset (m=0x1157e0, c=0, n=64176) >> >> >> >> > > > at >> >> >> >> > > > ../../../../../gcc-4.9.2/newlib/libc/string/memset.c:59 >> >> >> >> > > > 59 ../../../../../gcc-4.9.2/newlib/libc/string/memset.c: >> >> >> >> > > > No >> >> >> >> > > > such >> >> >> >> > > > file >> >> >> >> > > >> >> >> >> > > or >> >> >> >> > > >> >> >> >> > > > directory. >> >> >> >> > > > (gdb) s >> >> >> >> > > > 49 in >> >> >> >> > > > ../../../../../gcc-4.9.2/newlib/libc/string/memset.c >> >> >> >> > > > (gdb) s >> >> >> >> > > > _ARMV4_Exception_data_abort_default () >> >> >> >> > > > at >> >> >> >> > > >> >> >> >> > > >> >> >> >> > > >> >> >> >> > > >> >> >> >> > > >> >> >> >> > > ../../../../../../../../rtems-local/rtems/c/src/../../cpukit/score/cpu/ar >> >> >> >> > >m/armv4-exception-default.S:71 >> >> >> >> > > >> >> >> >> > > > 71 sub sp, #MORE_CONTEXT_SIZE >> >> >> >> > > > >> >> >> >> > > > When I set text section flag to ARMV7_MMU_READ_WRITE, the >> >> >> >> > > > system >> >> >> >> > > > starts >> >> >> >> > > > successfully. >> >> >> >> > > > >> >> >> >> > > >> -- >> >> >> >> > > >> Sebastian Huber, embedded brains GmbH >> >> >> >> > > >> >> >> >> >> > > >> Address : Dornierstr. 4, D-82178 Puchheim, Germany >> >> >> >> > > >> Phone : +49 89 189 47 41-16 >> >> >> >> > > >> Fax : +49 89 189 47 41-09 >> >> >> >> > > >> E-Mail : sebastian.hu...@embedded-brains.de >> >> >> >> > > >> PGP : Public key available on request. >> >> >> >> > > >> >> >> >> >> > > >> Diese Nachricht ist keine geschäftliche Mitteilung im >> >> >> >> > > >> Sinne >> >> >> >> > > >> des >> >> >> >> > > >> EHUG. >> >> >> >> > > > >> >> >> >> > > > _______________________________________________ >> >> >> >> > > > devel mailing list >> >> >> >> > > > devel@rtems.org >> >> >> >> > > > http://lists.rtems.org/mailman/listinfo/devel >> >> >> >> >> >> >> > >> >> >> > >> >> >> > >> >> >> > -- >> >> >> > Rohini Kulkarni >> >> >> > >> >> >> > _______________________________________________ >> >> >> > devel mailing list >> >> >> > devel@rtems.org >> >> >> > http://lists.rtems.org/mailman/listinfo/devel >> >> > >> >> > >> >> > >> >> > >> >> > -- >> >> > Rohini Kulkarni >> > >> > >> > >> > >> > -- >> > Rohini Kulkarni >> > >> > _______________________________________________ >> > devel mailing list >> > devel@rtems.org >> > http://lists.rtems.org/mailman/listinfo/devel > > > > > -- > Rohini Kulkarni _______________________________________________ devel mailing list devel@rtems.org http://lists.rtems.org/mailman/listinfo/devel
