RE: LinuxBIOS debugging with an emulator

  On Tue, 26 Oct 2004 Stephen.Kimball(a)bench.com wrote:
  
 Can someone tell me what the starting sequence is with LinuxBIOS?
 
 Reset jumps to crt0.s.  crt0.s calls auto.E.  auto.E is built using
 romcc, so source-level debugging is not possible.
 ah well :-)

 > The statement
 > locations can be found using the Lxxxx labels in linuxbios.map.
Then
  hardwaremain
is called. Hardwaremain is the first C function called.
 yep.

  Crt0 and auto run out of FLASH.  Hardwaremain is
the first function
 called after LinuxBIOS is copied to RAM.
 sounds good so far.

 ron
It seems that LinuxBIOS copies itself to _RAMBASE, which is 0x4000.
Then it branches to 0x4000 into _start, which sets up the stack and
calls hardwaremain.  The address of hardwaremain from linuxbios_c.o is
wrong.  The address is not the Flash address and it's not the RAM
address.  Can someone explain how linuxbios_c.o is linked with RAM
addresses?  

Steve

LinuxBIOS debugging with an emulator

[Li-Ta Lo]

      On Thu, 2004-10-28 at 16:03, Stephen.Kimball(a)bench.com wrote:
  
 It seems that LinuxBIOS copies itself to _RAMBASE, which is 0x4000.
 Then it branches to 0x4000 into _start, which sets up the stack and
 calls hardwaremain.  The address of hardwaremain from linuxbios_c.o is
 wrong.  The address is not the Flash address and it's not the RAM
 address.  Can someone explain how linuxbios_c.o is linked with RAM
 addresses?  
What do you mean ? In the S2885 I built, the _RAMBASE is 0x4000 and 
hardwaremain is 0x5fe0 as you can get from the linuxbios_c.map. They
are both in RAM. If you use "objdump -drS linuxbios_c.o" you will
find the hardwaremain is at offset 0x1fe0 from the _RAMBASSE.

BTW, if you specify the -g option for gcc, you can use the -S option
in objdump to see the source code with the disassebmly (-d).

Ollie


  Steve 
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LinuxBIOS debugging with an emulator

[Adam Sulmicki]

      On Thu, 28 Oct 2004, Li-Ta Lo wrote:

  BTW, if you specify the -g option for gcc, you can use
the -S option
 in objdump to see the source code with the disassebmly (-d).
BTW, this is a very usefull tip. I had been using it lately all the time
to trace ooops in kernel.

	objdump -S -C ./vmadump.ko  |less