[parisc-linux] Boot error on C200+

[Ryan Bradetich]

David Huggins-Daines wrote:

> Ryan Bradetich <rbradetich@uswest.net> writes:
>
> > Kernel Fault: Code=7 regs=c7f98248 (Addr=00000110)
> >
> > PSW  : 0004000b  GR 1 : 00002000  GR 2 : 00013403  GR 3 : 00000000
> > GR 4 : 2001ff74  GR 5 : 00000000  GR 6 : 000777f4  GR 7 : 000010c4
> > GR 8 : 000011bc  GR 9 : c7f98000  GR10 : c022fa78  GR11 : c0270030
> > GR12 : c0270008  GR13 : c022fe14  GR14 : c0270000  GR15 : 617bfdfb
> > GR16 : c027c60c  GR17 : 00000000  GR18 : c02b0000  GR19 : 00000001
> > GR20 : 00000037  GR21 : 00089b9c  GR22 : 00089bd8  GR23 : 000010c4
> > GR24 : 2001ff74  GR25 : 00000001  GR26 : 00000000  GR27 : 00088f00
> > GR28 : b64d8e60  GR29 : b44302d0  GR30 : 20020140  GR31 : 00022d63
> > SR0  : 00002000  SR1  : fffd2dff  SR2  : 00000000  SR3  : 00002000
> > SR4  : 00000000  SR5  : 00002000  SR6  : 00002000  SR7  : 00002000
> >
> > IASQ : 00000000 00000000 IAOQ : 00000110 00000114 ORIG_R28 : ffdf7fff
>                            ^^^^^^^^^^^^^^^^^^^^^^^^
>
> That is the syscall gateway page.  Note that the low bits of IAOQ are
> clear, so you are running in kernel mode and kernel space at this
> point.  Note also that the IAOQ points to just after the 'gate'
> instruction in linux_gateway_page, and from the look of the space
> registers, you've managed to successfully execute the instruction in
> the delay slot of the gate (mtsp %r0,%sr4) but nothing else.

I just wanted to verify I understood how you obtained this information...

hppa-linux-objdump -d vmlinux

c010d100 <linux_gateway_entry>:
c010d100:       00 00 e4 a1     mfsp sr7,r1
c010d104:       00 01 d8 20     mtsp r1,sr3
c010d108:       e8 00 20 00     b,gate c010d110 <linux_gateway_entry+0x10>,r0
c010d10c:       00 00 38 20     mtsp r0,sr4
c010d110:       00 00 78 20     mtsp r0,sr5

SR4 = 0, but SR5 != 0 ... therefore the delay slot of the gate instruction
executed.

> Note that GR20 is 0x37, which is the syscall number for fcntl(), which
> confirms your earlier findings :-)

From arch/parisc/kernel/syscall.S

        ENTRY_NAME(sys_ioctl)
        ENTRY_NAME(sys_fcntl)           /* 55 */
        ENTRY_NAME(sys_socketpair)

55 = 0x37 ....  I understand that....I don't see where GR20 is mapped to the
the syscall number.... (Not really important that I know now... but curious)

> >  IIR : 43ffff40 ISR : 00000000 IOR : 00000000
>
> That IIR doesn't look like any instruction on the syscall page that I
> know of.  Perhaps the gateway page is not getting mapped properly.
> The fact that it is trapping after the 'gate' instruction seems to
> support this.

From this statement, I assume it is a kernel problem and not a glibc
problem ... since the kernel would perform the mapping?  I'll start digging
around in the kernel and see what I can find.... any hints where to start?

Thanks for the replay and explanation.

Ryan


>
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