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[PATCH] util/cacheflush: Avoid flushing dcache twice when not necessary
From: |
Philippe Mathieu-Daudé |
Subject: |
[PATCH] util/cacheflush: Avoid flushing dcache twice when not necessary |
Date: |
Mon, 5 Jun 2023 21:59:11 +0200 |
<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(-)
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) {
+ /*
+ * 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
--
2.38.1
- [PATCH] util/cacheflush: Avoid flushing dcache twice when not necessary,
Philippe Mathieu-Daudé <=