1 files changed, 23 insertions, 1 deletions

diff --git a/firmware/crt0.S b/firmware/crt0.S
index 1e07e0c029..54432c9731 100644
--- a/firmware/crt0.S
+++ b/firmware/crt0.S
@@ -249,6 +249,9 @@ boot_table:
     /* Set up stack for IRQ mode */ 
     msr    cpsr_c, #0xd2
     ldr    sp, =irq_stack
+    /* Let abort mode use IRQ stack */
+    msr    cpsr_c, #0xd7
+    ldr    sp, =irq_stack
     /* Switch to supervisor mode */
     msr    cpsr_c, #0xd3
     ldr    sp, =stackend
@@ -278,18 +281,37 @@ ecode:
 ecodeend:
 
     .global irq
+    .global UIE
 
+/* All illegal exceptions call into UIE with exception address as first
+   parameter. This is calculated differently depending on which exception
+   we're in. Second parameter is exception number, used for a string lookup
+   in UIE.
+ */
 undef_instr_handler:
+    mov    r0, lr
+    mov    r1, #0
+    b      UIE
+
+/* We run supervisor mode most of the time, and should never see a software
+   exception being thrown. Perhaps make it illegal and call UIE?
+ */
 software_int_handler:
 reserved_handler:
     movs   pc, lr
 
 prefetch_abort_handler:
+    sub    r0, lr, #4
+    mov    r1, #1
+    b      UIE
+
 fiq_handler:
     subs   pc, lr, #4
 
 data_abort_handler:
-    subs   pc, lr, #8
+    sub    r0, lr, #8 
+    mov    r1, #2
+    b      UIE
 
 irq_handler:
     stmfd  sp!, {r0-r3, r12, lr}