Re: [PATCH v4 3/3] xen: add support for automatic debug key actions in case of crash

[Julien Grall <julien@xxxxxxx>]

Hi Juergen,

On 14/12/2020 07:56, Juergen Gross wrote:
> diff --git a/xen/common/keyhandler.c b/xen/common/keyhandler.c
> index de120fa092..806355ed8b 100644
> --- a/xen/common/keyhandler.c
> +++ b/xen/common/keyhandler.c
> @@ -3,7 +3,9 @@
>    */
>   
>   #include <asm/regs.h>
> +#include <xen/delay.h>
>   #include <xen/keyhandler.h>
> +#include <xen/param.h>
>   #include <xen/shutdown.h>
>   #include <xen/event.h>
>   #include <xen/console.h>
> @@ -519,6 +521,59 @@ void __init initialize_keytable(void)
>       }
>   }
>   
> +#define CRASHACTION_SIZE  32
> +static char crash_debug_panic[CRASHACTION_SIZE];
> +string_runtime_param("crash-debug-panic", crash_debug_panic);
> +static char crash_debug_hwdom[CRASHACTION_SIZE];
> +string_runtime_param("crash-debug-hwdom", crash_debug_hwdom);
> +static char crash_debug_watchdog[CRASHACTION_SIZE];
> +string_runtime_param("crash-debug-watchdog", crash_debug_watchdog);
> +#ifdef CONFIG_KEXEC
> +static char crash_debug_kexeccmd[CRASHACTION_SIZE];
> +string_runtime_param("crash-debug-kexeccmd", crash_debug_kexeccmd);
> +#else
> +#define crash_debug_kexeccmd NULL
> +#endif
> +static char crash_debug_debugkey[CRASHACTION_SIZE];
> +string_runtime_param("crash-debug-debugkey", crash_debug_debugkey);
> +
> +void keyhandler_crash_action(enum crash_reason reason)
> +{
> +    static const char *const crash_action[] = {
> +        [CRASHREASON_PANIC] = crash_debug_panic,
> +        [CRASHREASON_HWDOM] = crash_debug_hwdom,
> +        [CRASHREASON_WATCHDOG] = crash_debug_watchdog,
> +        [CRASHREASON_KEXECCMD] = crash_debug_kexeccmd,
> +        [CRASHREASON_DEBUGKEY] = crash_debug_debugkey,
> +    };
> +    static bool ignore;
> +    const char *action;
> +
> +    /* Some handlers are not functional too early. */
Can you explain in the commit message why this is necessary (An example 
would be useful)?
Cheers,

--
Julien Grall