Re: [PATCH] openrisc: make function cache_loop() inline

[Stafford Horne]

On Mon, Nov 12, 2018 at 11:55:44PM +0800, Changbin Du wrote:
> The third operand of mtspr instruction must be a constraint. To guarantee
> this condition, function cache_loop() which uses macro mtspr() must be
> inlined. So let's force it as 'inline'. This is to fix compiling error with
> new option CONFIG_NO_AUTO_INLINE.

Thanks for looking at this.

Do you mean, must be a 'constant'?

I think this fix is fine for now.  Can you add it to your 'kernel hacking: GCC
optimization for better debug experience' series?

> In file included from arch/openrisc/mm/cache.c:17:0:
> arch/openrisc/mm/cache.c: In function 'cache_loop':
> arch/openrisc/include/asm/spr.h:20:27: warning: asm operand 0 probably doesn't match constraints
>                               ^
> arch/openrisc/mm/cache.c:29:3: note: in expansion of macro 'mtspr'
>       mtspr(reg, line);
>       ^~~~~
> arch/openrisc/include/asm/spr.h:20:27: error: impossible constraint in 'asm'
> 
> Signed-off-by: Changbin Du <changbin.du@xxxxxxxxx>
> Reported-by: kbuild test robot <lkp@xxxxxxxxx>
> Cc: Stafford Horne <shorne@xxxxxxxxx>
> Cc: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>

Acked-by: Stafford Horne <shorne@xxxxxxxxx>

> ---
>  arch/openrisc/mm/cache.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/openrisc/mm/cache.c b/arch/openrisc/mm/cache.c
> index b747bf1fc1b6..4a4b2b6e006b 100644
> --- a/arch/openrisc/mm/cache.c
> +++ b/arch/openrisc/mm/cache.c
> @@ -20,7 +20,7 @@
>  #include <asm/cacheflush.h>
>  #include <asm/tlbflush.h>
>  
> -static void cache_loop(struct page *page, const unsigned int reg)
> +static inline void cache_loop(struct page *page, const unsigned int reg)
>  {
>  	unsigned long paddr = page_to_pfn(page) << PAGE_SHIFT;
>  	unsigned long line = paddr & ~(L1_CACHE_BYTES - 1);
> -- 
> 2.17.1
>