Re: [Xen-devel] [RFC 5/6] xen/console: Add noreturn attribute to panic function

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 05/01/2014 21:26, Julien Grall wrote:
> Panic function will never return. Without this attribute, gcc may output
> warnings in call function.
>
> Cc: Keir Fraser <keir@xxxxxxx>
> Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>

I have a longer series doing rather more noreturn'ing than just this, if
you can wait until the 4.5 dev window opens up again.

~Andrew

> ---
>  xen/drivers/char/console.c | 4 +++-
>  xen/include/xen/lib.h      | 2 +-
>  2 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/xen/drivers/char/console.c b/xen/drivers/char/console.c
> index f83c92e..229d48a 100644
> --- a/xen/drivers/char/console.c
> +++ b/xen/drivers/char/console.c
> @@ -1049,7 +1049,7 @@ __initcall(debugtrace_init);
>   * **************************************************************
>   */
>  
> -void panic(const char *fmt, ...)
> +void __attribute__((noreturn)) panic(const char *fmt, ...)
>  {
>      va_list args;
>      unsigned long flags;
> @@ -1092,6 +1092,8 @@ void panic(const char *fmt, ...)
>          watchdog_disable();
>          machine_restart(5000);
>      }
> +
> +    while ( 1 );
>  }
>  
>  void __bug(char *file, int line)
> diff --git a/xen/include/xen/lib.h b/xen/include/xen/lib.h
> index 5b258fd..9c3a242 100644
> --- a/xen/include/xen/lib.h
> +++ b/xen/include/xen/lib.h
> @@ -88,7 +88,7 @@ extern void printk(const char *format, ...)
>  extern void guest_printk(const struct domain *d, const char *format, ...)
>      __attribute__ ((format (printf, 2, 3)));
>  extern void panic(const char *format, ...)
> -    __attribute__ ((format (printf, 1, 2)));
> +    __attribute__ ((format (printf, 1, 2))) __attribute__ ((noreturn));
>  extern long vm_assist(struct domain *, unsigned int, unsigned int);
>  extern int __printk_ratelimit(int ratelimit_ms, int ratelimit_burst);
>  extern int printk_ratelimit(void);


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