Hi Daniel,
Thanks for your patch!
On Mon, Jan 8, 2024 at 10:32 AM Daniel Palmer <daniel@xxxxxxxx> wrote:
The plain old 68000 does not push the frame type/vector on the
stack when an interrupt starts like the brand new 68010 does.
;-)
This means that currently everything in struct pt_regs is
a bit off because it expects the processor to push an extra
short before the kernel interrupt code adds the rest.
In entry.S for the 68000 we already need to manually put
the vector number on the stack to work out what interrupt
is being handled because the cpu doesn't push that to the
stack.
So we can jiggle this around a bit to fix the issue:
- For 68000 use the same struct pt_regs layout as coldfire
where frame/vector is after pc and sp.
- In entry.S push the vector number first, the stack pointer
now lines up with the sktadj field in pt_regs and when saving
the remaining registers the offsets match the fields in the
struct.
- Remove the vec argument from the DragonBall interrupt
decoding logic as it's not pushed on the stack anymore
and not used either way.
Signed-off-by: Daniel Palmer <daniel@xxxxxxxx>
--- a/arch/m68k/include/uapi/asm/ptrace.h
+++ b/arch/m68k/include/uapi/asm/ptrace.h
@@ -39,7 +39,7 @@ struct pt_regs {
long d0;
long orig_d0;
long stkadj;
-#ifdef CONFIG_COLDFIRE
+#if defined(CONFIG_COLDFIRE) || defined(CONFIG_M68000)
unsigned format : 4; /* frame format specifier */
unsigned vector : 12; /* vector offset */
unsigned short sr;
I think it would be better to use the classic m68k stack frame.
That would pave the way for building a single nommu kernel for
MC680[012346]0 that runs on e.g. any Amiga.
MC68000 and Coldfire are incompatible anyway.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
