Hi!
I'm trying to boot gentoo install-sparc64-minimal-2008.0.iso
using qemu-system-sparc64 and it stops with SI message.
The problem is with code in first-isofs/crt0.S where it tries to
clear BSS, it is using %i3 register value to compute address.
It occurs that openbios image does not really care about
contents of %i3 before calling loaded silo code. So %i3 can
have odd value and subsequent store is faulting with
unaligned access.
Any hints on what does silo expect in %i3 are appreciated,
so we could amend openbios code to provide good initial
state to silo.
If I follow open firmware standard draft and clear %i3 before
control is passed to silo then it even allows me to boot gentoo
kernel (of course kernel crashes a bit later :) Still in this case
it is not clear why silo does those computations in the first place.
The silo code excerpt in question is below. Note that %i3 is
never assigned to in silo code before that 5 label. Fault is at
last std instruction (which is at pc=0x4064), qemu trace below.
--- silo-1.4.13/first-isofs/crt0.S ---
.align 32
jumphere:
/* Clear BSS */
5: add %l0, %i3, %l0
add %i1, %i3, %i1
andcc %i1, 4, %g0
sub %l0, %i1, %i2 ! %i2 = BSS length
be 1f
mov %g0, %g1
st %g0, [%i1]
add %i1, 4, %i1
1:
subcc %i2, 32, %i2
std %g0, [%i1]
---QEMU TRACE---
IN:
0x0000000000004060: subcc %i2, 0x20, %i2
0x0000000000004064: std %g0, [ %i1 ]
0x0000000000004068: std %g0, [ %i1 + 8 ]
0x000000000000406c: std %g0, [ %i1 + 0x10 ]
0x0000000000004070: std %g0, [ %i1 + 0x18 ]
0x0000000000004074: bgu 0x4060
0x0000000000004078: add %i1, 0x20, %i1
4254: Unaligned Memory Access (v=0034) pc=0000000000004064
npc=0000000000004068 SP=00000000ffe80201
pc: 0000000000004064 npc: 0000000000004068
General Registers:
%g0: 0000000000000000 %g1: 0000000000000000 %g2: 000001fe020003f8
%g3: 00000000ffe52ed0
%g4: 0000000000000000 %g5: 0000000000000020 %g6: 0000000000000000
%g7: 0000000000000000
Current Register Window:
%o0: 0000000000000000 %o1: 0000000000000000 %o2: 0000000000000000
%o3: 0000000000000000
%o4: 00000000ffd19928 %o5: 0000000000000001 %o6: 00000000ffe80201
%o7: 0000000000004000
%l0: 0000000000005db1 %l1: 0000000000005c30 %l2: 0000000000000000
%l3: 0000000000000000
%l4: 0000000000000000 %l5: 0000000000000000 %l6: 0000000000000000
%l7: 000000000000401c
%i0: 0000000000004000 %i1: 0000000000005c31 %i2: 0000000000000160
%i3: 0000000000000001
%i4: 00000000ffe808dc %i5: 0000000000000000 %i6: 00000000ffe802e1
%i7: 00000000ffd0bc90
--
Kind regards,
Igor V. Kovalenko
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