On Mon, 5 Jun 2023, 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.hender...@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <phi...@linaro.org>
---
Based-on: <20230605175647.88395-2-phi...@linaro.org>
---
util/cacheflush.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/util/cacheflush.c b/util/cacheflush.c
index de35616718..a08906155a 100644
--- a/util/cacheflush.c
+++ b/util/cacheflush.c
@@ -241,7 +241,14 @@ static void __attribute__((constructor))
init_cache_info(void)
void flush_idcache_range(uintptr_t rx, uintptr_t rw, size_t len)
{
- sys_dcache_flush((void *)rw, len);
+ if (rx == rw) {
Isn't it more straight forward to use rx != rw and drop the else branch
than having an empty if branch? You can still keep the comment above the
if to explain it if needed.
Regards,
BALATON Zoltan
+ /*
+ * sys_icache_invalidate() syncs the dcache and icache,
+ * so no need to call sys_dcache_flush().
+ */
+ } else {
+ sys_dcache_flush((void *)rw, len);
+ }
sys_icache_invalidate((void *)rx, len);
}
#else
