On Aug 24, 2011, at 12:47 PM, Matthias Reis wrote:
On Sun, Aug 7, 2011 at 23:09, Geert Uytterhoeven <geert@linux-
m68k.org>
wrote:
MFP interrupts are not autovector interrupts, but user vector
interrupts.
Sorry, I forgot about this: it may be a stack frame format issue,
which causes the kernel to
incorrectly identify the interrupt number.
user_inthandler() in arch/m68k/kernel/entry_mm.S looks at the
PT_OFF_FORMATVEC
field in the stack frame to identify the interrupt source. I don't
know from memory
if the plain 68000 stores it there. For autovector interrupts, it
doesn't, that's why
I created inidividual auto*_inthandler() functions that put an
hardcoded
number
on the stack instead of looking at the stack frame.
Hi Geert,
thanks for your kind reply. As far as I understand the 68000 manual
(http://www.freescale.com/files/archives/doc/ref_manual/M68000PRM.pdf,
section b.2), the CPU does not store the vector number on the
exception
stack. This is also what I've seen in the debugger: some seemingly
bogus
irq number is passed to m68k_handle_int. Any suggestions how to solve
this? I guess it is not a good idea to write an individual
user*_inthandler for each of the 255-64=191 possible user interrupts.
It's not out of the question. Although you wouldn't write 192 little
functions by hand -- just have stubs that push the vector number or
offset onto the stack and branch to another function, and generate
the stub code at runtime.
Josh
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