Re: [PATCH] util/cacheflush: Avoid flushing dcache twice when not necessary

[Richard Henderson]

On 6/5/23 12:59, Philippe Mathieu-Daudé wrote:
> <libkern/OSCacheControl.h> describes sys_icache_invalidate() as
> "equivalent to sys_cache_control(kCacheFunctionPrepareForExecution)",
> having kCacheFunctionPrepareForExecution defined as:
>
>    /* Prepare memory for execution.  This should be called
>     * after writing machine instructions to memory, before
>     * executing them.  It syncs the dcache and icache. [...]
>     */
>
> Since the dcache is also sync'd, we can avoid the sys_dcache_flush()
> call when both rx/rw pointers are equal.
>
> Suggested-by: Richard Henderson<richard.henderson@linaro.org>
> Signed-off-by: Philippe Mathieu-Daudé<philmd@linaro.org>
> ---
> Based-on:<20230605175647.88395-2-philmd@linaro.org>
> ---
>   util/cacheflush.c | 9 ++++++++-
>   1 file changed, 8 insertions(+), 1 deletion(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>


r~