Re: ofwboot, why does it work?

[Frank Wille <frank%phoenix.owl.de@localhost>]

On Thu, 18 Sep 2014 22:16:01 +0200
Artyom Tarasenko <atar4qemu%gmail.com@localhost> wrote:

> ok dev /client-services
> ok see getprop
> [...]
> Now it's only unclear why B50 was not affected as well.
> Do you by any chance have more OF machines?

Today I tested my Powerstack II, which runs FirmWorks. It shows exactly the
same code for getprop and copy-out as your emulated FirmWorks machine, and
ofwboot 1.12 made it crash. I didn't remember that, but I probably just used
an older ofwboot version to continue my tests in the past.

The new ofwboot with a 128K stack fixes it, so I committed the code and bumped
the version to 1.13.


Now I also wanted to test a recent kernel on it, but it fails very early
while attaching the cpu. I'm sure it went further in the past and listed
all devices, before a problem with PCI I/O- or Mem-space made it unusable.

---8<---
PowerPC Open Firmware                                                           
Version 1.2 RM11   Thu Jun 4 10:20:43 MST 1998                                  
Copyright Motorola 1995-96, All Rights Reserved                                 
Copyright FirmWorks 1995-96, All Rights Reserved                            

CPU . . . . . . . . . . . . . . . . . . . . . . . . . . . =PowerPC,Mach5        
MicroProcessor Internal Clock Speed (MHZ) . . . . . . . . =300                  
MicroProcessor External Clock Speed (MHZ) . . . . . . . . =67                   
PCI Bus Clock Speed (MHZ) . . . . . . . . . . . . . . . . =33                   
Local Memory Size . . . . . . . . . . . . . . . . . . . . =4000000 (64 MB)      
Memory Type . . . . . . . . . . . . . . . . . . . . . . . =EDO                  
Memory Error Checking . . . . . . . . . . . . . . . . . . =ECC                  
Memory Speed. . . . . . . . . . . . . . . . . . . . . . . =60 NS                
L2 Cache Size . . . . . . . . . . . . . . . . . . . . . . =256KB                
L2 Cache Type . . . . . . . . . . . . . . . . . . . . . . =Asynchronous         
L2 Cache Parity . . . . . . . . . . . . . . . . . . . . . =Disabled             
Configuration Checksum. . . . . . . . . . . . . . . . . . =Failed
                                                                                
Type any key to interrupt automatic selftest                                    
Rebooting with command: boot /pci/ethernet@4:192.168.0.5,ofwboot,192.168.0.10
Boot device: /pci/ethernet@4:192.168.0.5,ofwboot,192.168.0.10  File and args:   
\
>> NetBSD/ofppc OpenFirmware Boot, Revision 1.13 (Sun Sep 21 00:44:32 CEST 2014)
Using IP address: 192.168.0.10                                                  
root addr=192.168.0.5 path=/usr/local/data/export/powerstack/root
open /netbsd.ofppc: No such file or directory
Using IP address: 192.168.0.10
root addr=192.168.0.5 path=/usr/local/data/export/powerstack/root
3474276+152680 [171936+167715]=0x3c8b38
 start=0x100000
powerpc_fixup_stubs: 166 fixups done in 2856021 cycles
calling mem_regions                                   
regcnt=8 num=1 acell=1 scell=1
mem region 0 start=0 size=4000000
available                        
00004000 03ddc000 00000000 00000000
regcnt=8 num=1 acell=1 scell=1     
to OF_avail                   
0          
avail region 0 start=0x4000 size=0x3ddc000
Loaded initial symtab at 0x475c74, strtab at 0x49fc14, # entries 10727
Copyright (c) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
    2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014                 
    The NetBSD Foundation, Inc.  All rights reserved.   
Copyright (c) 1982, 1986, 1989, 1991, 1993           
    The Regents of the University of California.  All rights reserved.
                                                                      
NetBSD 7.99.1 (PWRSTK2) #0: Sun Sep 21 00:51:55 CEST 2014
        
frank@tethys:/home/frank/netbsd/current/src/objofppc/sys/arch/ofppc/compile/PWRSTK2
Model: MOT,PowerStack_II_Pro4000
total memory = 65536 KB         
avail memory = 57756 KB
kern.module.path=/stand/ofppc/7.99.1/modules
trap: pid 0.1 (system): kernel ALI trap @ 0x3d80000 by 0x23471c (DSISR 0x17d07)
Press a key to panic.
---8<---

The exception is caused by dcbz, while clearing allocated kernel memory:

db> bt
0x004ccbb0: at db_panic+0xe8
0x004ccbd0: at vpanic+0x13c 
0x004ccc00: at panic+0x4c  
0x004ccc40: at trap+0x164
0x004cccd0: kernel ALI trap @ 0x3d80000 (DSISR 0x17d07) pmap_zero_page+0xe8: 
srr1=0x1032                                                                     
  
            r1=0x4ccda0 cr=0x42422084 xer=0x20000000 ctr=0x2
0x004ccda0: at pmap_zero_page+0x18                          
0x004ccdb0: at uvm_pagealloc_strat+0x414
0x004cce10: at uvm_km_alloc+0x1e4       
0x004cce70: at softint_init+0x4c 
0x004cce90: at mi_cpu_attach+0xdc
0x004cceb0: at main+0x124        
0x004ccf10: at 0x1000d0  
db> x/i pmap_zero_page+0xe0,6                           
netbsd:pmap_zero_page+0xe0:     addi    r9, r0, 0x0
netbsd:pmap_zero_page+0xe4:     subf    r8, r11, r0
netbsd:pmap_zero_page+0xe8:     dcbz    r31, r9    
netbsd:pmap_zero_page+0xec:     dcbz    r31, r0
netbsd:pmap_zero_page+0xf0:     add     r0, r0, r11
netbsd:pmap_zero_page+0xf4:     add     r9, r9, r11

-- 
Frank Wille