[PATCH] arch/ppc/qemu: Move and simplify DSI and ISI exception handler routines

[BALATON Zoltan]

The routines are moved to avoid overwriting by the MorphOS boot code
which writes to address 0x80 during start up.

Signed-off-by: BALATON Zoltan

Index: openbios-devel/arch/ppc/qemu/start.S
===================================================================
--- openbios-devel/arch/ppc/qemu/start.S	(revision 1286)
+++ openbios-devel/arch/ppc/qemu/start.S	(working copy)
@@ -280,21 +280,6 @@
 1:	nop			//
    b	1b

-call_dsi_exception:
-	LOAD_REG_FUNC(r3, dsi_exception)
-	mtctr	r3
-	bctrl
-	b	exception_return
-
-call_isi_exception:
-	LOAD_REG_FUNC(r3, isi_exception)
-	mtctr	r3
-	bctrl
-	b	exception_return
-
-exception_return:
-	EXCEPTION_EPILOGUE
-
 trap_error:
    lis	r1, 0x8000			/* r1=0x80000000 */
    add.	r1,r1,r1			/* r1=r1+r1 (high 32bit !0) */
@@ -371,13 +356,19 @@

#endif

+VECTOR( 0x3000, "DSI_ISI" ):
 real_dsi:
    EXCEPTION_PREAMBLE
-	b	call_dsi_exception
+	LOAD_REG_FUNC(r3, dsi_exception)
+	b call_exception_handler

real_isi:
    EXCEPTION_PREAMBLE
-	b	call_isi_exception
+	LOAD_REG_FUNC(r3, isi_exception)
+call_exception_handler:
+	mtctr	r3
+	bctrl
+	EXCEPTION_EPILOGUE

GLOBL(__vectors_end):

[Mark Cave-Ayland]

On 12/04/14 13:18, BALATON Zoltan wrote:
> The routines are moved to avoid overwriting by the MorphOS boot code
> which writes to address 0x80 during start up.

Just thinking about a somewhat related SPARC experience here - does this 
mean that the PPC trap table is relocated to zero page memory somewhere 
further down in arch/ppc/qemu/start.S? (apologies for my lack of ability 
to read PPC assembly)

ATB,

Mark.

[BALATON Zoltan]

On Mon, 14 Apr 2014, Mark Cave-Ayland wrote:
> On 12/04/14 13:18, BALATON Zoltan wrote:
> > The routines are moved to avoid overwriting by the MorphOS boot code
> > which writes to address 0x80 during start up.
>
> Just thinking about a somewhat related SPARC experience here - does this mean 
> that the PPC trap table is relocated to zero page memory somewhere further 
> down in arch/ppc/qemu/start.S? (apologies for my lack of ability to read PPC 
> assembly)

It's not relocated but based off of __vectors which seems to be zero by 
default.

Regards,
BALATON Zoltan