linux booting fails on ppc440x5 with SRAM

[Vineeth _]

We ported the uboot Memory test and tested the 15MB ram and it was
successful.interestingly we have only 16MB SRAM in our board.We used 1
MB of RAM for the bootloader to execute and tested the other 15 MB.
i couldnt see any reason why the DEAR, MSR value become identical.
checked the objcopy of my linux image and the instruction on that
particular location was an ordinary branch instruction. !


On Fri, Oct 2, 2009 at 10:47 PM, Johnny Hung <johnny.hacking at gmail.com> wrote:
> It's seems a RAM initialize problem. Try to use ICE or your bootloader
> to test initialized RAM wirh write/read operation.
> Ex, use mtest in uboot to check memory. For ICE, it should be an
> detailed memory test function like hardware diagnostic.
>
> 2009/9/24 Benjamin Herrenschmidt <benh at kernel.crashing.org>:
>> On Wed, 2009-09-23 at 20:19 +0530, Vineeth _ wrote:
>>> I am trying to port linux on IBM powerpc-440x5. I have this board
>>> which has this processor, a 16MB SRAM sits on location 0x0, uart and a
>>> flash.I have a simple bootloader which does the following.
>>>     1. Initialize the processor (as part of it, we Generates the tlbs
>>> for UART,16MB flash,16MB SRAM)
>>>     2. Initialize the UART
>>>     3. Copy the simple-boot linux_image (binary file) from flash to
>>> 0x400000 location of SRAM.
>>>     4. Kernel entry to 0x400000
>>
>> Not sure yet, looks like things are being overwritten during boot.
>> Interestingly enough, the DEAR value looks like an MSR value..
>>
>> Hard to tell what's up. You'll have to dig a bit more youself to
>> figure out how come the kernel's getting that bad pointer.
>>
>> All I can tell you is that things work fine on 440x5 cores, though
>> I haven't tested a configuration with so little memory in a while.
>>
>> Ben.
>>
>>> zImage starting: loaded at 0x00400000 (sp: 0x004deeb0)
>>> Allocating 0x1dad84 bytes for kernel ...
>>> gunzipping (0x00000000 <- 0x0040c000:0x004dd3f1)...done 0x1c31cc bytes
>>>
>>> Linux/PowerPC load: console=ttyS0 root=/dev/ram
>>> Finalizing device tree... flat tree at 0x4eb300
>>> id mach(): done
>>> inside skybeam_register_console function
>>> MMU:enterMMU:hw initMMU:mapinMMU:setioMMU:exitinside
>>> _setup_arch-begininginside _setup_arch-1inside
>>> _setup_arch-2setup_arch: bootmemarch: exit<7>Top of RAM: 0x1000000,
>>> Total RAM: 0x1000000
>>> Zone PFN ranges:
>>>  DMA      0x00000000 -> 0x00001000
>>>  Normal   0x00001000 -> 0x00001000
>>> Movable zone start PFN for each node
>>> early_node_map[1] active PFN ranges
>>>    0: 0x00000000 -> 0x00001000
>>> MMU: Allocated 1088 bytes of context maps for 255 contexts
>>> Built 1 zonelists in Zone order, mobility grouping off.  Total pages: 4064
>>> Kernel command line: console=ttyS0 root=/dev/ram
>>> Unable to handle kernel paging request for data at address 0x00021000
>>> Faulting instruction address: 0xc010a7c4
>>> Oops: Kernel access of bad area, sig: 11 [#1]
>>> PREEMPT PowerPC 44x Platform
>>> Modules linked in:
>>> NIP: c010a7c4 LR: c010dc50 CTR: 00000000
>>> REGS: c01bfeb0 TRAP: 0300   Not tainted  (2.6.30)
>>> MSR: 00021000 <ME,CE>  CR: 24000044  XER: 00000000
>>> DEAR: 00021000, ESR: 00000000
>>> TASK = c01a94b8[0] 'swapper' THREAD: c01be000
>>> GPR00: 00001180 c01bff60 c01a94b8 00021000 00000025 00000008 c0104968 00000000
>>> GPR08: 2f72616d c0110000 c0155938 c01a0000 22000024 00000000 fffff104 00000000
>>> GPR16: 00000000 00000000 00000000 00000000 fffffff8 000008b8 c010d758 c0104968
>>> GPR24: 00001198 00001190 c018a001 c01c5498 000008c0 00001188 00021000 c01c42f0
>>> NIP [c010a7c4] strchr+0x0/0x3c
>>> LR [c010dc50] match_token+0x138/0x228
>>> Call Trace:
>>> [c01bff60] [c016b99c] 0xc016b99c (unreliable)
>>> [c01bffa0] [c0104a00] sort_extable+0x28/0x38
>>> [c01bffb0] [c01938ec] sort_main_extable+0x20/0x30
>>> [c01bffc0] [c018c734] start_kernel+0x140/0x288
>>> [c01bfff0] [c0000200] skpinv+0x190/0x1cc
>>> Instruction dump:
>>> 7ca903a6 88040000 38a5ffff 38840001 2f800000 98090000 39290001 419e0010
>>> 4200ffe4 98a90000 4e800020 4e800020 <88030000> 5484063e 7f802000 4d9e0020
>>> ---[ end trace 31fd0ba7d8756001 ]---
>>> Kernel panic - not syncing: Attempted to kill the idle task!
>>> Call Trace:
>>> [c01bfd90] [c0005d5c] show_stack+0x4c/0x16c (unreliable)
>>> [c01bfdd0] [c002f17c] panic+0xa0/0x168
>>> [c01bfe20] [c0032eb8] do_exit+0x61c/0x638
>>> [c01bfe60] [c000b60c] kernel_bad_stack+0x0/0x4c
>>> [c01bfe90] [c000f310] bad_page_fault+0x90/0xd8
>>> [c01bfea0] [c000e184] handle_page_fault+0x7c/0x80
>>> [c01bff60] [c016b99c] 0xc016b99c
>>> [c01bffa0] [c0104a00] sort_extable+0x28/0x38
>>> [c01bffb0] [c01938ec] sort_main_extable+0x20/0x30
>>> [c01bffc0] [c018c734] start_kernel+0x140/0x288
>>> [c01bfff0] [c0000200] skpinv+0x190/0x1cc
>>> Rebooting in 180 seconds..
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