On 27/03/2023 14.45, Nicholas Piggin wrote:
Check to ensure exception handlers are not being overwritten or
invalid exception numbers are used.
Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx>
---
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) {
You could check for the other "invalid exception handler" condition here
already, i.e. if (trap & ~0xf00) ...
I'd maybe simply do an "assert(!(trap & ~0xf00))" here.
+ printf("invalid exception handler %#x\n", trap);
+ abort();
+ }
+
trap >>= 8;
if (trap < 16) {
... then you could get rid of the if-statement here and remove one level of
indentation in the code below.
+ 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();
}
}
Thomas
