Date: Tue, 23 Apr 2013 12:31:38 -0400 From: John Baldwin <jhb@freebsd.org> To: Andriy Gapon <avg@freebsd.org> Cc: Jeremy Chadwick <jdc@koitsu.org>, freebsd-hackers@freebsd.org, Joshua Isom <jrisom@gmail.com>, Dimitry Andric <dim@freebsd.org> Subject: Re: Rebooting from loader causes a "fault" in VMware Workstation Message-ID: <201304231231.38765.jhb@freebsd.org> In-Reply-To: <5176B238.7030306@FreeBSD.org> References: <20130419162834.GA90217@icarus.home.lan> <006B20F1-F67B-4E9D-B0DF-D4ED843F7E8E@FreeBSD.org> <5176B238.7030306@FreeBSD.org>
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On Tuesday, April 23, 2013 12:09:28 pm Andriy Gapon wrote: > on 23/04/2013 17:36 Dimitry Andric said the following: > > I have tried to ascertain it actually arrives at this code when > > rebooting from the loader, but it does not seem to ever make it there, > > at least not to the jump to f000:fff0. Maybe VMware intercepts the > > switching back to real mode in the previous part, and dies on that, I am > > not sure. It is of course rather tricky to print off any debug messages > > at that point. :-) > > For the inquisitive minds here how last instructions (and CPU state) look > according to qemu log: > > IN: > 0x000000000000a030: xor %eax,%eax > 0x000000000000a032: int $0x30 > > ---------------- > IN: > 0x00000000000093e0: cmp $0x1,%eax > 0x00000000000093e3: jne 0x93ff > > ---------------- > IN: > 0x00000000000093ff: orb $0x1,%ss:0x9007 > 0x0000000000009407: jmp 0x90d2 > > ---------------- > IN: > 0x00000000000090d2: cli > 0x00000000000090d3: mov $0x1800,%esp > 0x00000000000090d8: mov %cr0,%eax > 0x00000000000090db: and $0x7fffffff,%eax > 0x00000000000090e0: mov %eax,%cr0 > > ---------------- > IN: > 0x00000000000090e3: xor %ecx,%ecx > 0x00000000000090e5: mov %ecx,%cr3 > > ---------------- > IN: > 0x00000000000090e8: lgdtl 0x95d0 > 0x00000000000090ef: ljmpw $0x18,$0x90f5 > > Triple fault > CPU Reset (CPU 0) > ESI=0004503c EDI=3fe50968 EBP=00094a80 ESP=00001800 > EIP=000090ef EFL=00000046 [---Z-P-] CPL=0 II=0 A20=1 SMM=0 HLT=0 > ES =0033 0000a000 ffffffff 00cff300 DPL=3 DS [-WA] > CS =0008 00000000 ffffffff 00cf9a00 DPL=0 CS32 [-R-] > SS =0010 00000000 ffffffff 00cf9300 DPL=0 DS [-WA] > DS =0033 0000a000 ffffffff 00cff300 DPL=3 DS [-WA] > FS =0033 0000a000 ffffffff 00cff300 DPL=3 DS [-WA] > GS =0033 0000a000 ffffffff 00cff300 DPL=3 DS [-WA] > LDT=0000 00000000 0000ffff 00008200 DPL=0 LDT > TR =0038 00005f98 00002067 00008900 DPL=0 TSS32-avl > GDT= ff85c789 00000000 This seems wrong (address is way too high). I wonder if the gdtdesc was trashed by something? Can you dump memory before the lgdtl instruction at the 0x95d0 address? -- John Baldwin
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