Greetings:
I am having a strange problem trying to single step through the kernel.
I have a custom 405GPr board that runs u-boot like a trained pig. Now
I'm on to the step of getting Linux up on the board. I am using
a BDI-2000 to debug the kernel (I load it into memory, and enter the
go command, and I get an exception).
So I tried to find the problem as follows:
BDI>load
Loading /tftpboot/vmlinuz.bdi , please wait ....
Loading program file passed
BDI>info
Target state : debug mode
Debug entry cause : JTAG stop request
Current PC : 0x00210000
Current CR : 0x00000000
Current MSR : 0x00000000
Current LR : 0x0021001c
BDI>md 0x00210000
00210000 : 7c7f1b78 7c9e2378 7cbd2b78 7cdc3378 |..x|.#x|.+x|.3x
00210010 : 7cfb3b78 3b000000 48002359 38001032 |.;x;...H.#Y8..2
00210020 : 7c1b03a6 3c00c000 600022d0 7c1a03a6 |...<...`.".|...
00210030 : 4c000064 00000000 00000000 00000000 L..d............
00210040 : 00000000 00000000 00000000 00000000 ................
00210050 : 00000000 00000000 00000000 00000000 ................
00210060 : 00000000 00000000 00000000 00000000 ................
00210070 : 00000000 00000000 00000000 00000000 ................
00210080 : 00000000 00000000 00000000 00000000 ................
00210090 : 00000000 00000000 00000000 00000000 ................
002100a0 : 00000000 00000000 00000000 00000000 ................
002100b0 : 00000000 00000000 00000000 00000000 ................
002100c0 : 00000000 00000000 00000000 00000000 ................
002100d0 : 00000000 00000000 00000000 00000000 ................
002100e0 : 00000000 00000000 00000000 00000000 ................
002100f0 : 00000000 00000000 00000000 00000000 ................
I disassembled head_4xx.o and so far this looks fine:
head_4xx.o: file format elf32-powerpc
Disassembly of section .text:
00000000 <_start>:
0: 7c 7f 1b 78 mr r31,r3
4: 7c 9e 23 78 mr r30,r4
8: 7c bd 2b 78 mr r29,r5
c: 7c dc 33 78 mr r28,r6
10: 7c fb 3b 78 mr r27,r7
14: 3b 00 00 00 li r24,0
18: 48 00 23 59 bl 2370 <initial_mmu>
Now I set a breakpoint as recommended in "tool talk" white paper by Ultimate
Solutions.
In System.map:
c00022c4 T abort
c00022d0 t start_here
c0002370 t initial_mmu
c00023d4 T set_context
c00023e4 t rest_init
BDI>bi 0xc00022d0
Breakpoint identification is 0
BDI>go
- Target started with DBCR0 = 0x80800001
BDI>
- TARGET: target has entered debug mode
BDI>info
Target state : debug mode
Debug entry cause : instruction breakpoint
Current PC : 0xc00022d0
Current CR : 0x00000000
Current MSR : 0x00001030
Current LR : 0x0021001c
So - I hit the breakpoint just fine - now I dump memory at start_here
and it is displayed below:
BDI>md 0xc00022d0
c00022d0 : 0223000d 00000a5f 2c019d00 003bd902 .#....._,....;..
c00022e0 : 23300b63 6d64002c 019e0000 00810223 #0.cmd.,.......#
c00022f0 : 3c0b6c65 6e002c01 9f000000 81022340 <.len.,.......#@
c0002300 : 0d000049 7d2c01a0 00000081 0223440d ...I},.......#D.
c0002310 : 0001d231 2c01a100 001a2e02 23480022 ...1,.......#H."
c0002320 : 00004158 00006b91 142c01a4 0b6f6800 ..AX..k..,...oh.
c0002330 : 2c01a500 003ebc02 23000b6c 656e002c ,....>..#..len.,
c0002340 : 01a60000 00810223 0c0d0001 d2312c01 .......#.....1,.
c0002350 : a7000041 58022310 000e0400 00011722 ...AX.#........"
c0002360 : 00004189 000015dc 3c2c01ac 0b696800 ..A.....<,...ih.
c0002370 : 2c01ad00 003e5402 23000d00 000a5f2c ,....>T.#....._,
c0002380 : 01ae0000 3bd90223 30002200 0041b400 ....;..#0."..A..
c0002390 : 006d2d70 2c01b10b 6f68002c 01b20000 .m-p,...oh.,....
c00023a0 : 3ebc0223 000d0001 952e2c01 b300003c >..#......,....<
c00023b0 : f3022310 00220000 41ee0000 6da3a02c ..#.."..A...m..,
c00023c0 : 01b80b69 68002c01 b900003e 54022300 ...ih.,....>T.#.
Problem is if I look at the disassemble code at start_here I see:
000022d0 <start_here>:
22d0: 3c 40 00 00 lis r2,0
22d4: 60 42 00 00 ori r2,r2,0
22d8: 3c 82 40 00 addis r4,r2,16384
22dc: 38 84 02 70 addi r4,r4,624
22e0: 7c 93 43 a6 mtsprg 3,r4
22e4: 38 60 00 00 li r3,0
22e8: 7c 72 43 a6 mtsprg 2,r3
Which does not match at all what I see above and hence when I use the
command
"go":
BDI>go
- Target started with DBCR0 = 0x80800001
# Step timeout detected
BDI>info
Target state : debug mode
Debug entry cause : JTAG stop request
Current PC : 0x00000700
Current CR : 0x00000000
Current MSR : 0x00001000
Current LR : 0x0021001c
I get an exception indicating that an invalid opcode was fetched.
I can't figure out what to try next - Any ideas?
Thanks
Jerry Walden
Below is my cfg file for the BDI-2000:
;
[INIT]
; init core register
WSPR 954 0x00000000 ;DCWR: Disable data cache write-thru
WSPR 1018 0x00000000 ;DCCR: Disable data cache
WSPR 1019 0x00000000 ;ICCR: Disable instruction cache
WSPR 982 0x00000000 ;EVPR: Exception Vector Table @0x0000000
; Setup Peripheral Bus
WDCR 18 0x00000010 ;Select PB0AP
WDCR 19 0x9B015480 ;PB0AP: Flash and SRAM
WDCR 18 0x00000000 ;Select PB0CR
WDCR 19 0xFFF18000 ;PB0CR: 1MB at 0xFFF00000, r/w, 8bit
WDCR 18 0x00000011 ;Select PB1AP
WDCR 19 0x02815480 ;PB1AP: NVRAM and RTC
WDCR 18 0x00000001 ;Select PB1CR
WDCR 19 0xF0018000 ;PB1CR: 1MB at 0xF0000000, r/w, 8bit
WDCR 18 0x00000012 ;Select PB2AP
WDCR 19 0x04815A80 ;PB2AP: Keyboard and Mouse
WDCR 18 0x00000002 ;Select PB2CR
WDCR 19 0xF0118000 ;PB2CR: 1MB at 0xF0100000, r/w, 8bit
WDCR 18 0x00000013 ;Select PB3AP
WDCR 19 0x01815280 ;PB3AP: IRDA
WDCR 18 0x00000003 ;Select PB3CR
WDCR 19 0xF0218000 ;PB3CR: 1MB at 0xF0200000, r/w, 8bit
WDCR 18 0x00000017 ;Select PB7AP
WDCR 19 0x01815280 ;PB7AP: FPGA
WDCR 18 0x00000007 ;Select PB7CR
WDCR 19 0xF0318000 ;PB7CR: 1MB at 0xF0300000, r/w, 8bit
; Setup SDRAM Controller
WDCR 16 0x00000080 ;Select SDTR1
WDCR 17 0x0086400D ;SDTR1: SDRAM Timing Register
WDCR 16 0x00000040 ;Select MB0CF
WDCR 17 0x00046001 ;MB0CF: 16MB @ 0x00000000
WDCR 16 0x00000048 ;Select MB2CF
WDCR 17 0x01046001 ;MB2CF: 16MB @ 0x01000000
WDCR 16 0x00000030 ;Select RTR
WDCR 17 0x05F00000 ;RTR: Refresh Timing Register
WDCR 16 0x00000020 ;Select MCOPT1
WDCR 17 0x80800000 ;MCOPT1: Enable SDRAM Controller
; Setup MMU info
WM32 0x000000f4 0x00000000 ;invalidate kernel page table base
WM32 0x000000f8 0x00000000 ;invalidate process page table base
WM32 0x000000f0 0xc00000f4 ;invalidate page table base
[TARGET]
;WAKEUP 3000 ;wakeup time after reset
;VECTOR CATCH ;catch unhandled exceptions
;SIO 7 9600 ;TCP port for serial IO
JTAGCLOCK 1 ;use 16 MHz JTAG clock
CPUTYPE 405 ;the used target CPU type
BDIMODE AGENT ;the BDI working mode (LOADONLY | AGENT)
BREAKMODE HARD ;SOFT or HARD, HARD uses PPC hardware
breakpoint
STEPMODE HWBP ;JTAG or HWBP, HWPB uses one or two hardware
breakpoints
MMU XLAT 0xC0000000 ;enable virtual address mode
PTBASE 0x000000f0 ;address where kernel/user stores pointer to
page table
;REGLIST SPR ;select register to transfer to GDB
;REGLIST ALL ;select register to transfer to GDB
;SCANPRED 2 2 ;JTAG devices connected before PPC400
;SCANSUCC 3 3 ;JTAG devices connected after PPC400
[HOST]
IP 192.168.0.123
FILE /tftpboot/vmlinuz.bdi
FORMAT BIN 0x00200000
START 0x00210000
LOAD MANUAL ;load code MANUAL or AUTO after reset
DEBUGPORT 2001
DUMP /tmp/dump.bin ;Linux: dump.bin must already exist and
public writable
[FLASH]
WORKSPACE 0x00004000 ;workspace in target RAM for fast programming
algorithm
CHIPTYPE AM29F ;Flash type (AM29F | AM29BX8 | AM29BX16 | I28BX8 |
I28BX16)
CHIPSIZE 0x80000 ;The size of one flash chip in bytes (e.g. AM29F040
= 0x80000)
BUSWIDTH 8 ;The width of the flash memory bus in bits (8 | 16 |
32)
FILE u-boot.srec
ERASE 0xFFF80000 ;erase sector 0 of flash in U7 (AM29F040)
ERASE 0xFFF90000 ;erase sector 1 of flash
ERASE 0xFFFA0000 ;erase sector 2 of flash
ERASE 0xFFFB0000 ;erase sector 3 of flash
ERASE 0xFFFC0000 ;erase sector 4 of flash
ERASE 0xFFFD0000 ;erase sector 5 of flash
ERASE 0xFFFE0000 ;erase sector 6 of flash
ERASE 0xFFFF0000 ;erase sector 7 of flash
[REGS]
IDCR1 0x010 0x011 ;MEMCFGADR and MEMCFGDATA
IDCR2 0x012 0x013 ;EBCCFGADR and EBCCFGDATA
IDCR3 0x014 0x015 ;KIAR and KIDR
FILE reg405gp.def
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