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Re: [Qemu-devel] Openbios upgrade broke sparc32 linux.
From: |
Olivier Danet |
Subject: |
Re: [Qemu-devel] Openbios upgrade broke sparc32 linux. |
Date: |
Thu, 04 Jul 2013 23:52:45 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130625 Thunderbird/17.0.7 |
On 29/06/2013 22:29, Olivier Danet wrote:
On 28/06/2013 23:44, Mark Cave-Ayland wrote:
On 28/06/13 03:08, Rob Landley wrote:
Commit 467b34689d27 upgraded the openbios image, and ever since my
linux
system images hang about the time they try to initialize interrupts.
http://landley.net/aboriginal/bin/system-image-sparc.tar.bz2
Extract that and "./run-emulator.sh" in the tarball. Using qemu 1.2.0
for example works fine, you get a shell prompt. Using 1.5.0 hangs.
Rob
Hi Rob,
Thanks for the bug report. I did a quick bisect on OpenBIOS and it
points to the following commit:
commit 167aafd70f64e74a77787ca5bf9f4dc750b27fc3
Author: blueswirl <address@hidden>
Date: Sun Feb 3 16:50:11 2013 +0000
SPARC32: microSPARC-II identification
For the microSPARC-II = Fujitsu MB86904 = Sun STP1012PGA,
PSR.IMPL=0 and PSR.VERS=4.
This CPU model is used as default by QEMU when emulating
a SparcStation-4 or SparcStation-5.
Signed-off-by: Olivier DANET <address@hidden>
Signed-off-by: Blue Swirl <address@hidden>
The commit itself is very simple and looks like this:
http://git.qemu.org/?p=openbios.git;a=commitdiff;h=0fe772df8717ef75d91eae8ef221e9966ce2fd7f.
My guess would be that Linux is trying to do some slightly different
initialisation based upon identifying the CPU, but I'm not too
familiar with the kernel code myself. Blue/Olivier - can either of
you comment on this?
ATB,
Mark.
How embarrassing...
- QEMU 1.5.1 can boot Debian Etch (kernel 2.6.18), RedHat 4.2 (kernel
2.0.30), NetBSD 6.1 and OpenBSD 5.3.
- Your image (Linux 3.8) can be started with a TurboSparc CPU : qemu
-cpu "Fujitsu MB86907".
- My SparcStation-5 has a 110MHz MicroSPARC-II and the .attributes
(aka .properties) fields are identical
to OpenBIOS values, except for the mask_rev : I have 0x26, OpenBIOS
sets 0x23
Before the patch, OpenBIOS had an incoherence between the PSR register
content and the BIOS defined values.
In Linux "arch/sparc/mm/srmmu.c:get_srmmu_type(void)", this correspond
to "a TurboSparc emulating Swift".
(Swift is the MS-2).
TurboSPARC could be the new QEMU default, but, ideally, the MS-II
should be preferred
as it is compatible with more OSes ( hoping to run NextStep in QEMU
one day ...).
Maybe recent Linux kernels are not compatible with the way QEMU
emulates the MS-II...
Regards
Olivier
[temlib.org]
Hello
I think I have found the problem.
Each SPARC CPU model use different MMU TLB management functions.
For Linux, the callbacks are set in arch/sparc/mm/srmmu.c :
xxx_flush_tlb_all, xxx_flush_tlb_mm, xxx_flush_tlb_range,
xxx_flush_tlb_page.
The assembly code used for the MicroSparcII is arch/sparc/mm/swift.S.
This code accesses the vm_mm member of vm_area_struct
(include/linux/mm_types.h)
The position of the vm_mm field in the structure was modified recently,
and the assembly
was not adjusted accordingly.
(https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/include/linux/mm_types.h?id=e4c6bfd2d79d063017ab19a18915f0bc759f32d9)
The bug was introduced in Linux 3.8
Here is a patch for swift, there are also issues in hypersparc.S,
viking.S, tsunami.S ...:
==========================================================================
diff -up linux_prev/arch/sparc/mm/swift.S linux/arch/sparc/mm/swift.S
--- linux_prev/arch/sparc/mm/swift.S 2013-07-04 23:16:37.785273225 +0200
+++ linux/arch/sparc/mm/swift.S 2013-07-04 23:30:50.445310001 +0200
@@ -105,7 +105,7 @@ swift_flush_cache_mm_out:
.globl swift_flush_cache_range
swift_flush_cache_range:
- ld [%o0 + 0x0], %o0 /* XXX vma->vm_mm, GROSS
XXX */
+ ld [%o0 + 0x20], %o0 /* XXX vma->vm_mm, GROSS
XXX */
sub %o2, %o1, %o2
sethi %hi(4096), %o3
cmp %o2, %o3
@@ -116,7 +116,7 @@ swift_flush_cache_range:
.globl swift_flush_cache_page
swift_flush_cache_page:
- ld [%o0 + 0x0], %o0 /* XXX vma->vm_mm, GROSS
XXX */
+ ld [%o0 + 0x20], %o0 /* XXX vma->vm_mm, GROSS
XXX */
70:
ld [%o0 + AOFF_mm_context], %g2
cmp %g2, -1
@@ -219,7 +219,7 @@ swift_flush_sig_insns:
.globl swift_flush_tlb_range
.globl swift_flush_tlb_all
swift_flush_tlb_range:
- ld [%o0 + 0x00], %o0 /* XXX vma->vm_mm GROSS XXX */
+ ld [%o0 + 0x20], %o0 /* XXX vma->vm_mm GROSS XXX */
swift_flush_tlb_mm:
ld [%o0 + AOFF_mm_context], %g2
cmp %g2, -1
@@ -233,7 +233,7 @@ swift_flush_tlb_all_out:
.globl swift_flush_tlb_page
swift_flush_tlb_page:
- ld [%o0 + 0x00], %o0 /* XXX vma->vm_mm GROSS XXX */
+ ld [%o0 + 0x20], %o0 /* XXX vma->vm_mm GROSS XXX */
mov SRMMU_CTX_REG, %g1
ld [%o0 + AOFF_mm_context], %o3
andn %o1, (PAGE_SIZE - 1), %o1
==========================================================================
For a cleaner fix, arch/sparc/kernel/asm_offsets.c should be modified.
Cool !
Olivier
[temlib.org]
- Re: [Qemu-devel] Openbios upgrade broke sparc32 linux.,
Olivier Danet <=