[kvm-unit-tests v3 03/13] powerpc: Add some checking to exception handler install

[Nicholas Piggin]

Check to ensure exception handlers are not being overwritten or
invalid exception numbers are used.

Signed-off-by: Nicholas Piggin <npig...@gmail.com>
---
Since v2:
- New patch

 lib/powerpc/processor.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/lib/powerpc/processor.c b/lib/powerpc/processor.c
index ec85b9d..70391aa 100644
--- a/lib/powerpc/processor.c
+++ b/lib/powerpc/processor.c
@@ -19,11 +19,23 @@ static struct {
 void handle_exception(int trap, void (*func)(struct pt_regs *, void *),
                      void * data)
 {
+       if (trap & 0xff) {
+               printf("invalid exception handler %#x\n", trap);
+               abort();
+       }
+
        trap >>= 8;
 
        if (trap < 16) {
+               if (func && handlers[trap].func) {
+                       printf("exception handler installed twice %#x\n", trap);
+                       abort();
+               }
                handlers[trap].func = func;
                handlers[trap].data = data;
+       } else {
+               printf("invalid exception handler %#x\n", trap);
+               abort();
        }
 }
 
-- 
2.37.2