[PATCH] powerpc/powernv/memtrace: Fix dcache flushing

Trace memory is cleared and the corresponding dcache lines
are flushed after allocation. However, this should not be
done using the PFN. This adds the missing __va() conversion.

Fixes: 2ac02e5ecec0 ("powerpc/mm: Remove dcache flush from memory remove.")
Signed-off-by: Sandipan Das <redacted>
---
 arch/powerpc/platforms/powernv/memtrace.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/memtrace.c b/arch/powerpc/platforms/powernv/memtrace.c
index 71c1262589fe..a31f13814f2e 100644
--- a/arch/powerpc/platforms/powernv/memtrace.c
+++ b/arch/powerpc/platforms/powernv/memtrace.c

@@ -104,8 +104,8 @@ static void memtrace_clear_range(unsigned long start_pfn,
 	 * Before we go ahead and use this range as cache inhibited range
 	 * flush the cache.
 	 */
-	flush_dcache_range_chunked(PFN_PHYS(start_pfn),
-				   PFN_PHYS(start_pfn + nr_pages),
+	flush_dcache_range_chunked((unsigned long)__va(PFN_PHYS(start_pfn)),
+				   (unsigned long)__va(PFN_PHYS(start_pfn + nr_pages)),
 				   FLUSH_CHUNK_SIZE);
 }
 

-- 
2.25.1

Sandipan Das [off-list ref] writes:

Trace memory is cleared and the corresponding dcache lines
are flushed after allocation. However, this should not be
done using the PFN. This adds the missing __va() conversion.

Reviewed-by: Aneesh Kumar K.V <redacted>

Le 30/04/2021 à 09:55, Sandipan Das a écrit :

Can you use pfn_to_virt() instead ?

  				   FLUSH_CHUNK_SIZE);
  }
  

On 30/04/21 2:12 pm, Christophe Leroy wrote:

Le 30/04/2021 à 09:55, Sandipan Das a écrit :

quoted

Trace memory is cleared and the corresponding dcache lines
are flushed after allocation. However, this should not be
done using the PFN. This adds the missing __va() conversion.

Fixes: 2ac02e5ecec0 ("powerpc/mm: Remove dcache flush from memory remove.")
Signed-off-by: Sandipan Das <redacted>
---
  arch/powerpc/platforms/powernv/memtrace.c | 4 ++--
  1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/memtrace.c b/arch/powerpc/platforms/powernv/memtrace.c
index 71c1262589fe..a31f13814f2e 100644
--- a/arch/powerpc/platforms/powernv/memtrace.c
+++ b/arch/powerpc/platforms/powernv/memtrace.c

@@ -104,8 +104,8 @@ static void memtrace_clear_range(unsigned long start_pfn,

       * Before we go ahead and use this range as cache inhibited range
       * flush the cache.
       */
-    flush_dcache_range_chunked(PFN_PHYS(start_pfn),
-                   PFN_PHYS(start_pfn + nr_pages),
+    flush_dcache_range_chunked((unsigned long)__va(PFN_PHYS(start_pfn)),
+                   (unsigned long)__va(PFN_PHYS(start_pfn + nr_pages)),

Can you use pfn_to_virt() instead ?

quoted

                     FLUSH_CHUNK_SIZE);
  }
 

Sure, that looks cleaner. Thanks for the suggestion.

- Sandipan