[OpenBIOS] [PATCH 1/2] arch/ppc/qemu: Moved exception handlers from beginning of RAM

BALATON Zoltan balaton at eik.bme.hu
Wed May 28 21:03:40 CEST 2014


Do not put exception handler routines between 0x00-0xff as some OSes
use this area for their own purposes and can corrupt them. (In
particular MorphOS writes to 0x80 during boot). This patch frees up
this area by moving the routines that were there higher.

Signed-off-by: BALATON Zoltan <balaton at eik.bme.hu>
---
 openbios-devel/arch/ppc/qemu/start.S | 32 +++++++++++++-------------------
 1 file changed, 13 insertions(+), 19 deletions(-)

diff --git a/openbios-devel/arch/ppc/qemu/start.S b/openbios-devel/arch/ppc/qemu/start.S
index db8e860..ae2fd53 100644
--- a/openbios-devel/arch/ppc/qemu/start.S
+++ b/openbios-devel/arch/ppc/qemu/start.S
@@ -280,20 +280,8 @@ GLOBL(__vectors):
 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
+VECTOR( 0x100, "SRE" ):
+        b       _entry
 
 trap_error:
 	lis	r1, 0x8000			/* r1=0x80000000 */
@@ -309,9 +297,6 @@ trap_error:
 	mtctr r4
 	bctr
 
-VECTOR( 0x100, "SRE" ):
-        b       _entry
-
 ILLEGAL_VECTOR( 0x200 )
 
 VECTOR( 0x300, "DSI" ):
@@ -373,11 +358,20 @@ VECTOR( 0x2200, "ISI_64" ):
 
 real_dsi:
 	EXCEPTION_PREAMBLE
-	b	call_dsi_exception
+	LOAD_REG_FUNC(r3, dsi_exception)
+	mtctr	r3
+	bctrl
+	b exception_return
 
 real_isi:
 	EXCEPTION_PREAMBLE
-	b	call_isi_exception
+	LOAD_REG_FUNC(r3, isi_exception)
+	mtctr	r3
+	bctrl
+	b exception_return
+
+exception_return:
+	EXCEPTION_EPILOGUE
 
 GLOBL(__vectors_end):
 
-- 
1.8.1.5




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