Re: [Qemu-devel] [PATCH] MIPS: Fix dmtc0 instruction

[Thiemo Seufer <ths@networkno.de>]

Aurelien Jarno wrote:
> On Sat, Aug 23, 2008 at 06:42:34PM +0200, Hervé Poussineau wrote:
> > Hi,
> > 
> > In gen_dmtc0 function, TCG temporary variable t0 is freed at the end of
> > the function. Variable is freed again in the gen_dmtc0 caller.
> > I removed the free in gen_dmtc0, to do like in gen_dmfc0, gen_mfc0,
> > gen_mtc0.
> > 
> > Incidentally, this unregresses NetBSD on Pica 61.
>  
> This was also affecting Linux MIPS64 and I have noticed the problem this
> morning (though it seems to be a few weeks old).

My old 64-bit testcase worked for some reason despite that bug. The current
debian/testing kernel image for malta/5kc failed, though.

> I have applied the patch, and also removed another tcg_temp_free(t0)
> which has been left. Thanks!

I can confirm it works here as well, thank you. However, I still see
QEMU hang with the debian kernel at IDE detection:

[...]
[    2.040127] pcnet32.c:v1.34-NAPI 14.Aug.2007 tsbogend@alpha.franken.de
[    2.040127] pcnet32: PCnet/PCI II 79C970A at 0x1020, 52:54:00:12:34:56 assigned IRQ 10.
[    2.040127] eth0: registered as PCnet/PCI II 79C970A
[    2.040127] pcnet32: 1 cards_found.
[    2.040127] Uniform Multi-Platform E-IDE driver
[    2.040127] ide: Assuming 33MHz system bus speed for PIO modes; override with idebus=xx
[    2.040127] PIIX4: IDE controller (0x8086:0x7111 rev 0x00) at  PCI slot 0000:00:0a.1
[    2.040127] PCI: Enabling device 0000:00:0a.1 (0000 -> 0001)
[    2.040127] PIIX4: not 100% native mode: will probe irqs later
[    2.040127]     ide0: BM-DMA at 0x1040-0x1047, BIOS settings: hda:PIO, hdb:PIO
[    2.040127]     ide1: BM-DMA at 0x1048-0x104f, BIOS settings: hdc:PIO, hdd:PIO

I figure CONFIG_NO_HZ has too high demands on the count/compare emulation.


Thiemo