* Patch by Hans-Joerg Frieden, 06 Dec 2002

[karo-tx-uboot.git] / cpu / ppc4xx / start.S

diff --git a/cpu/ppc4xx/start.S b/cpu/ppc4xx/start.S
index baaaba4fab15c2a7236d92797d22d39483c125e4..c40a8dba8b160c506f64148cfc05993005072ee9 100644 (file)
--- a/cpu/ppc4xx/start.S
+++ b/cpu/ppc4xx/start.S
@@ -775,7 +775,14 @@ SystemCall:
        add     r11,r11,r0
        lwz     r11,0(r11)
 
-       li      r12,0xd00-4*3           /* save LR & SRRx */
+       li      r20,0xd00-4             /* Get stack pointer */
+       lwz     r12,0(r20)
+       subi    r12,r12,12              /* Adjust stack pointer */
+       li      r0,0xc00+_end_back-SystemCall
+       cmplw   0, r0, r12              /* Check stack overflow */
+       bgt     1f
+       stw     r12,0(r20)
+
        mflr    r0
        stw     r0,0(r12)
        mfspr   r0,SRR0
@@ -800,7 +807,9 @@ _back:
        mtmsr   r11
        SYNC
 
-       li      r12,0xd00-4*3           /* restore regs */
+       li      r12,0xd00-4             /* restore regs */
+       lwz     r12,0(r12)
+
        lwz     r11,0(r12)
        mtlr    r11
        lwz     r11,4(r12)
@@ -808,8 +817,13 @@ _back:
        lwz     r11,8(r12)
        mtspr   SRR1,r11
 
+       addi    r12,r12,12              /* Adjust stack pointer */
+       li      r20,0xd00-4
+       stw     r12,0(r20)
+
        SYNC
        rfi
+_end_back:
 
        STD_EXCEPTION(0xd00, SingleStep, UnknownException)