RE: [ECOS] RedBoot hits fetch instruction trap

[Kurt Siedenburg <kurt.siedenburg@vicom.com>]

What I do see from the stuff below would result in data abort exceptions on other architectures - but not in instruction fetch exceptions:
  -  The instructions themselves are in valid address space, are all well aligned and seem to be valid opcodes 
  -  But the data those instructions fetch may not be valid addresses (00000000, FFFFFFFF)
Again I'm not familiar with SPARC - and its CPU exception architecture.

Sorry - I don't think I can help any further.
  Kurt

-----Original Message-----
From: Les Miklosy [mailto:lgm0@verizon.net] 
Sent: Wednesday, July 30, 2014 11:18 PM
To: Kurt Siedenburg
Cc: ecos-discuss@ecos.sourceware.org
Subject: Re: [ECOS] RedBoot hits fetch instruction trap

Hope the following is useful information. I used the -nb -nswb switches when starting grmon to remove the erroneous exception notices. With a break point at RedBoot's _rb_gets I still see multiple traps (think grmon creates the last one in each list). The instruction at 0x4000bee8 is _rb_gets_preloaded. After a 'cont' command the process is trapped and neither RedBoot nor grmon returns control to the user.

Anyone have a clue?   Here is the sequence just described:

grmon2> go 0
   breakpoint 1 hit
   0x4000c5a4: c02a0000  clrb  [%o0]

grmon2> hist
       TIME     ADDRESS   INSTRUCTIONS/AHB SIGNALS      RESULT/DATA
      98758063  4000AE00  or  %l0, 0x298, %o0           [4001FA98]
      98758064  4000C5AC  AHB read   mst=0  size=2      [7FFFFE4B]
      98758065  4000C5B0  AHB read   mst=0  size=2      [9E104000]
      98758066  4000C5B4  AHB read   mst=0  size=2      [01000000]
      98758067  4000C5B8  AHB read   mst=0  size=2      [9DE3BF90]
      98758068  4000C5BC  AHB read   mst=0  size=2      [9210001A]
      98758070  4000AE04  mov  256, %o1                 [00000100]
      98758071  4000AE08  call  0x4000C5A4              [4000AE08]
      98758072  4000AE0C  mov  10, %o2                  [0000000A]
      98758073  4000C5A4  clrb  [%o0]                   [  TRAP  ]

grmon2> step 10
   0x4000c5a4: c02a0000  clrb  [%o0]
   0x4000c5a8: 8213c000  or  %o7, %g1
   0x4000c5ac: 7ffffe4b  call  0x4000BED8
   0x4000c5b0: 9e104000  or  %g1, %o7
   0x4000bed8: 9de3bf90  save  %sp, -112, %sp
   0x4000bedc: 1110004e  sethi  %hi(0x40013800), %o0
   0x4000bee0: ea022390  ld  [%o0 + 0x390], %l5
   0x4000bee4: a4100018  mov  %i0, %l2
   0x4000bee8: d24e0000  ldsb  [%i0], %o1
   0x4000beec: a6102000  mov  0, %l3

grmon2> hist
       TIME     ADDRESS   INSTRUCTIONS/AHB SIGNALS      RESULT/DATA
      98758147  40013B90  AHB read   mst=0  size=2      [FFFFFFFF]
      98758148  4000BEE0  ld  [%o0 + 0x390], %l5        [FFFFFFFF]
      98758149  4000BEE4  mov  %i0, %l2                 [  TRAP  ]
      98758155  4000BEE4  mov  %i0, %l2                 [4001FA98]
      98758156  4000BEE8  ldsb  [%i0], %o1              [  TRAP  ]
      98758169  4001FA98  AHB read   mst=0  size=2      [00656C70]
      98758170  4000BEE8  ldsb  [%i0], %o1              [00000000]
      98758171  4000BEEC  mov  0, %l3                   [  TRAP  ]
      98758177  4000BEEC  mov  0, %l3                   [00000000]
      98758178  4000BEF0  cmp  %o1                      [  TRAP  ]

grmon2> cont

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