From: Grant Grundler <grundler@puffin.external.hp.com>
To: parisc-linux@lists.parisc-linux.org
Subject: [parisc-linux] r3 getting trashed by __wake_up?
Date: Thu, 19 Jul 2001 01:51:15 -0600 [thread overview]
Message-ID: <200107190751.BAA09784@puffin.external.hp.com> (raw)
Hi parisc asm experts! ;^)
The problem I'm seeing is r3 is zero'd (trashed) by __wake_up()
when called by wake_up_parent(). I'm triggering this consistently
with "pon uunet" - ie fire up a ppp dialup session. The c3k crashes
after the modem returns a "CONNECT" string.
The c3k data page faults with:
Kernel Fault: Code=26 regs=8e6a4740 (Addr=00000098)
IOAQ and GR02 are both wake_up_parent+24
(called from skip_save_ior+164)
"objdump -rD kernel/signal.o" shows:
0000000000000000 <wake_up_parent>:
0: 6b c2 3f d9 stw rp,-14(sp)
4: 6f c4 00 80 stw,ma r4,40(sp)
8: 6b c3 3f 89 stw r3,-3c(sp)
c: 08 1a 02 44 copy r26,r4
10: 08 04 02 43 copy r4,r3
14: 34 19 00 02 ldi 1,r25
18: 34 7a 01 50 ldo a8(r3),r26
1c: e8 00 a0 00 call 24 <wake_up_parent+0x24>
1c: R_PARISC_PCREL22F __wake_up
20: 08 19 02 58 copy r25,r24
24: 48 73 01 30 ldw 98(r3),r19
28: 36 63 3e d1 ldo -98(r19),r3
...
r3 is zero. But it obviously wasn't zero before calling __wake_up.
Now __wake_up save/restore of registers is a bit wierd...
It doesn't look right to me but it's been a long day:
0000000000000000 <__wake_up>:
0: 08 03 02 41 copy r3,r1
4: 6b c2 3f d9 stw rp,-14(sp)
8: 08 1e 02 43 copy sp,r3
c: 6f c1 01 00 stw,ma r1,80(sp)
10: 0c 6d 12 90 stw r13,8(sr0,r3)
...
c8: 0c 70 10 8d ldw 8(sr0,r3),r13
...
f0: 34 7e 00 80 ldo 40(r3),sp
f4: e8 40 d0 00 ret
f8: 4f c3 3f 81 ldw,mb -40(sp),r3
I didn't see any code inbetween that modifies r3.
And from this code it looks like r3 is callee save.
Shouldn't sp be restored with "copy r3,sp"?
And the restore of r3 be "ldw 0(sp),r3"?
Everything on my c3k is up-to-date and vmlinux was built native from scratch:
gcc-3.0 | 1:3.0-1 | unstable | hppa, hurd-i386
gcc-3.0 | 1:3.0-4 | unstable | alpha, arm, i386, mips, mipsel, powerpc, sparc
Perhaps we just need to rebuild/use the newer gcc bits?
Other ideas?
thanks,
grant
next reply other threads:[~2001-07-19 7:52 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-07-19 7:51 Grant Grundler [this message]
2001-07-19 10:50 ` [parisc-linux] r3 getting trashed by __wake_up? Alan Modra
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