[kvm-unit-tests v4 02/12] powerpc: Add some checking to exception handler install

[Thomas Huth]

On 08/06/2023 09.58, Nicholas Piggin wrote:
> Check to ensure exception handlers are not being overwritten or
> invalid exception numbers are used.
> 
> Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
> ---
> Since v3:
> - Simplified code as suggested by Thomas.
> 
>   lib/powerpc/processor.c | 10 +++++++---
>   1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/lib/powerpc/processor.c b/lib/powerpc/processor.c
> index 05b4b04f..0550e4fc 100644
> --- a/lib/powerpc/processor.c
> +++ b/lib/powerpc/processor.c
> @@ -19,12 +19,16 @@ static struct {
>   void handle_exception(int trap, void (*func)(struct pt_regs *, void *),
>   		      void * data)
>   {
> +	assert(!(trap & ~0xf00));
> +
>   	trap >>= 8;
>   
> -	if (trap < 16) {
> -		handlers[trap].func = func;
> -		handlers[trap].data = data;
> +	if (func && handlers[trap].func) {
> +		printf("exception handler installed twice %#x\n", trap);
> +		abort();
>   	}
> +	handlers[trap].func = func;
> +	handlers[trap].data = data;
>   }
>   
>   void do_handle_exception(struct pt_regs *regs)

Reviewed-by: Thomas Huth <thuth at redhat.com>