As the TOC pointer can be corrupted by the main program,
we must restore it in the exception handler.
As we know where we are loaded, we can now compute it easily.
To compute it only in the common part of the exception handler
(call_handler), store the address of call_handler at an absolute
address in memory to be able to call the handler from the exception
table (as SLOF does).
Reported-by: Thomas Huth <thuth@xxxxxxxxxx>
Signed-off-by: Laurent Vivier <lvivier@xxxxxxxxxx>
---
v2: don't add SPAPR_KERNEL_LOAD_ADDR to r2 as
the TOC has been relocated and have directly the good
value. The problem has been reported by Thomas.
powerpc/cstart64.S | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/powerpc/cstart64.S b/powerpc/cstart64.S
index c47b67d..2d66032 100644
--- a/powerpc/cstart64.S
+++ b/powerpc/cstart64.S
@@ -13,6 +13,8 @@
#include "spapr.h"
+#define P_HANDLER 0x2ff8
+
.section .init
/*
@@ -46,6 +48,11 @@ start:
add r4, r4, r31
bl relocate
+ /* compute address of call_handler */
+
+ LOAD_REG_ADDR(r4, call_handler)
+ std r4, P_HANDLER(0)
+
/* relocate vector table to base address 0x0 (MSR_IP = 0) */
/* source: r4, dest end: r5, destination: r6 */
@@ -166,6 +173,11 @@ call_handler:
mfsrr1 r0
std r0, _MSR(r1)
+ /* restore TOC pointer */
+
+ LOAD_REG_IMMEDIATE(r31, SPAPR_KERNEL_LOAD_ADDR)
+ ld r2, (p_toc - start)(r31)
+
/* FIXME: build stack frame */
/* call generic handler */
@@ -221,7 +233,7 @@ call_handler:
mfctr r0
std r0,_CTR(r1)
- LOAD_REG_ADDR(r0, call_handler)
+ ld r0, P_HANDLER(0)
mtctr r0
li r0,\vec
@@ -245,3 +257,5 @@ VECTOR(0x900)
.align 7
.globl __end_interrupts
__end_interrupts:
+ .org P_HANDLER
+ .llong 0
--
2.5.5
--
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