RTEMS - SPARC ut700 fp disabled exception upon RTEMS startup

Jiri Gaisler jiri at gaisler.se
Sat Oct 22 14:48:24 UTC 2016


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?

Jiri.

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/
> <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).
> rtems-4.10.99.0(SPARC/w/FPU/leon3)
>  
>  
>  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 255.255.255.0, address 139.169.132.128
>    gateway 139.169.132.1, dns1 139.169.132.1, 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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> devel at rtems.org
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