RTEMS - SPARC ut700 fp disabled exception upon RTEMS startup

Duran, Steve (JSC-ER611) steve.duran-1 at nasa.gov
Sun Oct 23 19:27:05 UTC 2016

I would prefer not to compile with soft float as the processors that we are using have hardware FPUs.  Is there a recommended rtems and rtems source builder branch rev that should be used?

I am running CentOS
CentOS Linux release 7.2.1511 (Core)
Linux spartan117 3.10.0-327.22.2.el7.x86_64 #1 SMP Thu Jun 23 17:05:11 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

It has gcc:
$ gcc --version
gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-4)

But, if I understand the RTEMS builder correctly, it downloads a version of tools and libs to build itself.  It looks like it used gcc 4.9.3.
$ sparc-rtems4.11-gcc -v
Using built-in specs.
Target: sparc-rtems4.11
Configured with: ../gcc-4.9.3/configure --prefix=/gfe/RTEMS/development/rtems/4.11 --bindir=/gfe/RTEMS/development/rtems/4.11/bin --exec_prefix=/gfe/RTEMS/development/rtems/4.11 --includedir=/gfe/RTEMS/development/rtems/4.11/include --libdir=/gfe/RTEMS/development/rtems/4.11/lib --libexecdir=/gfe/RTEMS/development/rtems/4.11/libexec --mandir=/gfe/RTEMS/development/rtems/4.11/share/man --infodir=/gfe/RTEMS/development/rtems/4.11/share/info --datadir=/gfe/RTEMS/development/rtems/4.11/share --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=sparc-rtems4.11 --disable-libstdcxx-pch --with-gnu-as --with-gnu-ld --verbose --with-newlib --with-system-zlib --disable-nls --without-included-gettext --disable-win32-registry --enable-version-specific-runtime-libs --disable-lto --enable-newlib-io-c99-formats --enable-newlib-iconv --enable-newlib-iconv-encodings=big5,cp775,cp850,cp852,cp855,cp866,euc_jp,euc_kr,euc_tw,iso_8859_1,iso_8859_10,iso_8859_11,iso_8859_13,iso_8859_14,iso_8859_15,iso_8859_2,iso_8859_3,iso_8859_4,iso_8859_5,iso_8859_6,iso_8859_7,iso_8859_8,iso_8859_9,iso_ir_111,koi8_r,koi8_ru,koi8_u,koi8_uni,ucs_2,ucs_2_internal,ucs_2be,ucs_2le,ucs_4,ucs_4_internal,ucs_4be,ucs_4le,us_ascii,utf_16,utf_16be,utf_16le,utf_8,win_1250,win_1251,win_1252,win_1253,win_1254,win_1255,win_1256,win_1257,win_1258 --enable-threads --disable-plugin --enable-libgomp --enable-languages=c,c++
Thread model: rtems
gcc version 4.9.3 20150626 (RTEMS 4.11, RSB 1675a733536d1aec2020011e5e522497a442561a, Newlib (GCC)

On Oct 22, 2016, at 9:48 AM, Jiri Gaisler <jiri at gaisler.se<mailto:jiri at gaisler.se>> wrote:

It seems that you have compiled RTEMS with a gcc version that can use %fpu registers to move integer data. The work-around could be to compile the kernel with -msoft-float, or to move to a (later) version of gcc that does not do this anymore. Which gcc version do you use?


On 22/10/16 01:22, Duran, Steve (JSC-ER611) wrote:
I am trying to get and RTEMS kernel to boot on the SPARC ut700 development board. There appears to be an issue in the RTEMS networking code that must use floating point, but for some reason the FPU has been disabled.

Details below.  Any insights into how to resolve this issue would be appreciated.

Development environment setup on:
Setup on:
CentOS Linux release 7.2.1511 (Core)
Linux spartan117 3.10.0-327.22.2.el7.x86_64 #1 SMP Thu Jun 23 17:05:11 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

$ git clone git://git.rtems.org/rtems.git rtems
$ git checkout -b rtems411 origin/4.11

Loading through grmon2, starting to run, error messages, and some debug info:

  GRMON2 LEON debug monitor v2.0.74 32-bit pro version

  Copyright (C) 2016 Cobham Gaisler - All rights reserved.
  For latest updates, go to http://www.gaisler.com/
  Comments or bug-reports to support at gaisler.com<mailto:support at gaisler.com>

  using port /dev/ttyUSB4 @ 460800 baud
  Device ID:           0x699
  GRLIB build version: 4110
  Detected system:     UT699E/UT700
  Detected frequency:  125 MHz

  Component                            Vendor
  LEON3-FT SPARC V8 Processor          Cobham Gaisler
  AHB Debug UART                       Cobham Gaisler
  JTAG Debug Link                      Cobham Gaisler
  Fast 32-bit PCI Bridge               Cobham Gaisler
  PCI/AHB DMA controller               Cobham Gaisler
  GR Ethernet MAC                      Cobham Gaisler
  GRSPW2 SpaceWire Serial Link         Cobham Gaisler
  GRSPW2 SpaceWire Serial Link         Cobham Gaisler
  GRSPW2 SpaceWire Serial Link         Cobham Gaisler
  GRSPW2 SpaceWire Serial Link         Cobham Gaisler
  MIL-STD-1553B Interface              Cobham Gaisler
  Memory controller with EDAC          Cobham Gaisler
  AHB/APB Bridge                       Cobham Gaisler
  LEON3 Debug Support Unit             Cobham Gaisler
  AHB/APB Bridge                       Cobham Gaisler
  OC CAN AHB interface                 Cobham Gaisler
  Generic UART                         Cobham Gaisler
  Multi-processor Interrupt Ctrl.      Cobham Gaisler
  Modular Timer Unit                   Cobham Gaisler
  Clock gating unit                    Cobham Gaisler
  PCI Arbiter                          European Space Agency
  General Purpose I/O port             Cobham Gaisler
  AHB Status Register                  Cobham Gaisler
  SPI Controller                       Cobham Gaisler
  General Purpose Register             Cobham Gaisler

  Use command 'info sys' to print a detailed report of attached cores

  40085000 .eefs_ram                512.0kB / 512.0kB   [===============>] 100%
  40000000 .tarfs_ram               530.0kB / 530.0kB   [===============>] 100%
  40405000 .text                    815.8kB / 815.8kB   [===============>] 100%
  404D0F20 .rtemsroset                304B              [===============>] 100%
  404D1050 .data                     13.3kB /  13.3kB   [===============>] 100%
  404D4560 .jcr                         4B              [===============>] 100%
  Total size: 1.83MB (362.50kbit/s)
  Entry point 0x40405000
  Image /home/sduran/sparc_leon3/SPARC_LEON3_Workspace/ut700/rtems4.11-kernel/rki.elf loaded

RTEMS Kernel Image Booting

*** RTEMS Info ***
COPYRIGHT (c) 1989-2008.
On-Line Applications Research Corporation (OAR).

 BSP Ticks Per Second = 100
*** End RTEMS info ***

Populating Root file system from TAR file.
Starting RTEMS network configuration
RTEMS network config: All structures filled out, now calling init functions
Convert ethernet address
Converting: 00:00:7a:cc:00:16
Calling rtems_bsdnet_initialize_network
greth: driver attached
**** PHY ****
Vendor: 80017   Device: 9   Revision: 0
Current Operating Mode: 100 Mbit Full Duplex
Autonegotiation Time: 1739ms
RTEMS bsdnet_initialize_network returned OK
Hostname is gfe02.local
   Device gr_eth1, netmask, address
   gateway, dns1, dns2 (null)

Starting the FTP Server.
syslog: ftpd: FTP daemon started (1 session max)
Setting up filesystems.
Initializing Local Commands.
Running /shell-init.

1: mkdir ram0
2: mkdir ram
3: mkrfs /dev/rd0
4: mount -t rfs /dev/rd0 /ram0
mounted /dev/rd0 -> /ram0
5: hello
Hello RTEMS!
Create your own command here!
Starting shell....

RTEMS Shell on /dev/console. Use 'help' to list commands.
[/] # Unexpected trap (0x04) at address 0x404A6764
fp disabled

  Program exited normally.

>From UT700_LEON_Functional_Manual.pdf
Trap table on page 18:
TRAP        TT   PRI  Description
fp_disabled 0x04 6    FP instruction while FPU disabled

grmon2> dis 0x404A6764
       0x404a6764: d11861b0  ldd  [%g1 + 0x1B0], %f8      <_svfprintf_r+100>
       0x404a6768: a410a250  or  %g2, 0x250, %l2          <_svfprintf_r+104>
       0x404a676c: 39101341  sethi  %hi(0x404D0400), %i4  <_svfprintf_r+108>

grmon2> bt
  Inside trap/irq

       %pc          %sp
  #0   0x40417e40   0x404e6158   <syscall+0>
  #1   0x404ba880   0x404e61b8   <_CPU_Fatal_halt+0x8>
  #2   0x40442d68   0x404e6218   <_Terminate+0x48>
  #3   0x40441720   0x404e6288   <rtems_fatal+0xc>
  #4   0x40416044   0x404e62e8   <bsp_spurious_handler+0xc>
  #5   0x404bae24   0x404e6350
  #6   0x404a6710   0x40528180   <_svfprintf_r+0x10>
  #7   0x404a20b4   0x40528428   <sprintf+0x50>
  #8   0x4046eb68   0x40528500   <inet_ntop4+0x1c>
  #9   0x4046ee90   0x40528570   <inet_ntop+0x2e8>
  #10  0x4046eb3c   0x40528628   <inet_ntoa+0x54>
  #11  0x40474a90   0x40528690   <arplookup+0xb8>
  #12  0x404754c0   0x405286f8   <arpintr+0x1d4>
  #13  0x40434048   0x40528788   <networkDaemon+0xa8>
  #14  0x40433db4   0x405287f0   <taskEntry+0x1c>
  #15  0x40499058   0x40528850   <_Thread_Handler+0xb8>
  #16  0x40498fa0   0x405288b0   <_Thread_Handler+0>

So it would appear that RTEMS is in networking code, calling sprintf, trying to perform a floating point operation but for some reason the FPU has been disabled.

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