[U-Boot] [PATCH v2 3/5] Introduce CONFIG_ENABLE_BUG_CHECKS to disable BUG{_ON} by default

[Lothar Waßmann]

Hi,

On Mon,  4 Dec 2017 12:37:02 +0900 Masahiro Yamada wrote:
> BUG() and BUG_ON() are generally used to test a condition that should
> never happen.  If it does, it is a bug.
> 
> Linux always enables them, but doing so in U-Boot causes image size
> problems on some platforms.  Introduce CONFIG_ENABLE_BUG_CHECKS to
> make them no-op by default.  Platforms without image size constraint
> are free to enable this option to catch bugs easily.
> 
> Likewise, silence WARN_ON() unless this option is enabled.
> 
> Suggested-by: Tom Rini <trini at konsulko.com>
> Signed-off-by: Masahiro Yamada <yamada.masahiro at socionext.com>
> ---
> 
> Changes in v2:
>   - Newly added
> 
>  include/linux/bug.h | 9 ++++++++-
>  lib/Kconfig         | 7 +++++++
>  2 files changed, 15 insertions(+), 1 deletion(-)
> 
> diff --git a/include/linux/bug.h b/include/linux/bug.h
> index f07bb71..ac1c7de 100644
> --- a/include/linux/bug.h
> +++ b/include/linux/bug.h
> @@ -6,17 +6,24 @@
>  #include <linux/compiler.h>
>  #include <linux/printk.h>
>  
> +#ifdef CONFIG_ENABLE_BUG_CHECKS
>  #define BUG() do { \
>  	printk("BUG at %s:%d/%s()!\n", __FILE__, __LINE__, __func__); \
>  	panic("BUG!"); \
>  } while (0)
> +#define __WARN() 	\
> +	printk("WARNING at %s:%d/%s()!\n", __FILE__, __LINE__, __func__)
> +#else
> +#define BUG()
> +#define __WARN()
> +#endif
>  
>  #define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0)
>  
>  #define WARN_ON(condition) ({						\
>  	int __ret_warn_on = !!(condition);				\
>  	if (unlikely(__ret_warn_on))					\
> -		printk("WARNING at %s:%d/%s()!\n", __FILE__, __LINE__, __func__); \
> +		__WARN();						\
>  	unlikely(__ret_warn_on);					\
>  })
>  
> diff --git a/lib/Kconfig b/lib/Kconfig
> index 00ac650..36b1b3b 100644
> --- a/lib/Kconfig
> +++ b/lib/Kconfig
> @@ -45,6 +45,13 @@ config USE_TINY_PRINTF
>  
>  	  The supported format specifiers are %c, %s, %u/%d and %x.
>  
> +config ENABLE_BUG_CHECKS
> +	bool "Enable BUG/BUG_ON() checks and WARN_ON() logs"
> +	help
This should be 'default y' IMO to keep the current behaviour for all
existing platforms.


Lothar Waßmann