Re: [PATCH] m68k/coldfire: flush cache when creating the signal stack frame

[Alexander Stein <alexander.stein@systec-electronic.com>]

Any feedback on this?

On Wednesday 05 June 2013 13:42:39, Alexander Stein wrote:
> When the signal stack frame is created, it must be flushed in order to
> make sure the cache fetches the correct data.
> Without cache flush the icache might pick up old cached data from an older
> signal stack frame if the signal is raised again very fast.
> In case of copyback the data cache muist be pushed first, but is untested.
> 
> Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
> ---
>  arch/m68k/kernel/signal.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/arch/m68k/kernel/signal.c b/arch/m68k/kernel/signal.c
> index 2a16df3..57fd286 100644
> --- a/arch/m68k/kernel/signal.c
> +++ b/arch/m68k/kernel/signal.c
> @@ -50,6 +50,7 @@
>  #include <asm/pgtable.h>
>  #include <asm/traps.h>
>  #include <asm/ucontext.h>
> +#include <asm/cacheflush.h>
>  
>  #ifdef CONFIG_MMU
>  
> @@ -181,6 +182,13 @@ static inline void push_cache (unsigned long vaddr)
>  		asm volatile ("movec %0,%%caar\n\t"
>  			      "movec %1,%%cacr"
>  			      : : "r" (vaddr + 4), "r" (temp));
> +	} else {
> +		/* CPU_IS_COLDFIRE */
> +#if defined(CONFIG_CACHE_COPYBACK)
> +		flush_cf_dcache(0, DCACHE_MAX_ADDR);
> +#endif
> +		/* Invalidate instruction cache for the pushed bytes */
> +		clear_cf_icache(vaddr, vaddr + 8);
>  	}
>  }
>  
> 
-- 
Dipl.-Inf. Alexander Stein

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