On 12/11/19 4:46 PM, Pierre Morel wrote:
> Define two functions to register and to unregister a call back for IO
> Interrupt handling.

How about:
Let's make it possible to add and remove a custom io interrupt handler,
that can be used instead of the normal one.

> 
> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
> Reviewed-by: Thomas Huth <thuth@redhat.com>
> Reviewed-by: David Hildenbrand <david@redhat.com>
> ---
>  lib/s390x/interrupt.c | 23 ++++++++++++++++++++++-
>  lib/s390x/interrupt.h |  7 +++++++
>  2 files changed, 29 insertions(+), 1 deletion(-)
>  create mode 100644 lib/s390x/interrupt.h
> 
> diff --git a/lib/s390x/interrupt.c b/lib/s390x/interrupt.c
> index 05f30be..b70aafd 100644
> --- a/lib/s390x/interrupt.c
> +++ b/lib/s390x/interrupt.c
> @@ -10,9 +10,9 @@
>   * under the terms of the GNU Library General Public License version 2.
>   */
>  #include <libcflat.h>
> -#include <asm/interrupt.h>
>  #include <asm/barrier.h>
>  #include <sclp.h>
> +#include <interrupt.h>
>  
>  static bool pgm_int_expected;
>  static bool ext_int_expected;
> @@ -141,12 +141,33 @@ void handle_mcck_int(void)
>  		     lc->mcck_old_psw.addr);
>  }
>  
> +static void (*io_int_func)(void);
> +
>  void handle_io_int(void)
>  {
> +	if (*io_int_func)
> +		return (*io_int_func)();
> +
>  	report_abort("Unexpected io interrupt: at %#lx",
>  		     lc->io_old_psw.addr);
>  }
>  
> +int register_io_int_func(void (*f)(void))
> +{
> +	if (io_int_func)
> +		return -1;
> +	io_int_func = f;
> +	return 0;
> +}

Not completely sure why this isn't a bool, but ok.

> +
> +int unregister_io_int_func(void (*f)(void))
> +{
> +	if (io_int_func != f)
> +		return -1;
> +	io_int_func = NULL;
> +	return 0;
> +}
> +
>  void handle_svc_int(void)
>  {
>  	report_abort("Unexpected supervisor call interrupt: at %#lx",
> diff --git a/lib/s390x/interrupt.h b/lib/s390x/interrupt.h
> new file mode 100644
> index 0000000..e945ef7
> --- /dev/null
> +++ b/lib/s390x/interrupt.h
> @@ -0,0 +1,7 @@
> +#ifndef __INTERRUPT_H
> +#include <asm/interrupt.h>
> +
> +int register_io_int_func(void (*f)(void));
> +int unregister_io_int_func(void (*f)(void));
> +
> +#endif
>