diff --git linux-libre-5.4.255-gnu1/Makefile linux-libre-5.4.256-gnu1/Makefile
index d54cc8aa6cd1..36fa1deae87b 100644
--- linux-libre-5.4.255-gnu1/Makefile
+++ linux-libre-5.4.256-gnu1/Makefile
@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 VERSION = 5
 PATCHLEVEL = 4
-SUBLEVEL = 255
+SUBLEVEL = 256
 EXTRAVERSION = -gnu1
 NAME = Kleptomaniac Octopus
 
diff --git linux-libre-5.4.255-gnu1/arch/mips/alchemy/common/dbdma.c linux-libre-5.4.256-gnu1/arch/mips/alchemy/common/dbdma.c
index e9ee9ab90a0c..4ca2c28878e0 100644
--- linux-libre-5.4.255-gnu1/arch/mips/alchemy/common/dbdma.c
+++ linux-libre-5.4.256-gnu1/arch/mips/alchemy/common/dbdma.c
@@ -30,7 +30,6 @@
  *
  */
 
-#include <linux/dma-map-ops.h> /* for dma_default_coherent */
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/slab.h>
@@ -624,18 +623,17 @@ u32 au1xxx_dbdma_put_source(u32 chanid, dma_addr_t buf, int nbytes, u32 flags)
 		dp->dscr_cmd0 &= ~DSCR_CMD0_IE;
 
 	/*
-	 * There is an erratum on certain Au1200/Au1550 revisions that could
-	 * result in "stale" data being DMA'ed. It has to do with the snoop
-	 * logic on the cache eviction buffer.  dma_default_coherent is set
-	 * to false on these parts.
+	 * There is an errata on the Au1200/Au1550 parts that could result
+	 * in "stale" data being DMA'ed. It has to do with the snoop logic on
+	 * the cache eviction buffer.  DMA_NONCOHERENT is on by default for
+	 * these parts. If it is fixed in the future, these dma_cache_inv will
+	 * just be nothing more than empty macros. See io.h.
 	 */
-	if (!dma_default_coherent)
-		dma_cache_wback_inv(KSEG0ADDR(buf), nbytes);
+	dma_cache_wback_inv((unsigned long)buf, nbytes);
 	dp->dscr_cmd0 |= DSCR_CMD0_V;	/* Let it rip */
 	wmb(); /* drain writebuffer */
 	dma_cache_wback_inv((unsigned long)dp, sizeof(*dp));
 	ctp->chan_ptr->ddma_dbell = 0;
-	wmb(); /* force doorbell write out to dma engine */
 
 	/* Get next descriptor pointer. */
 	ctp->put_ptr = phys_to_virt(DSCR_GET_NXTPTR(dp->dscr_nxtptr));
@@ -687,18 +685,17 @@ u32 au1xxx_dbdma_put_dest(u32 chanid, dma_addr_t buf, int nbytes, u32 flags)
 			  dp->dscr_source1, dp->dscr_dest0, dp->dscr_dest1);
 #endif
 	/*
-	 * There is an erratum on certain Au1200/Au1550 revisions that could
-	 * result in "stale" data being DMA'ed. It has to do with the snoop
-	 * logic on the cache eviction buffer.  dma_default_coherent is set
-	 * to false on these parts.
+	 * There is an errata on the Au1200/Au1550 parts that could result in
+	 * "stale" data being DMA'ed. It has to do with the snoop logic on the
+	 * cache eviction buffer.  DMA_NONCOHERENT is on by default for these
+	 * parts. If it is fixed in the future, these dma_cache_inv will just
+	 * be nothing more than empty macros. See io.h.
 	 */
-	if (!dma_default_coherent)
-		dma_cache_inv(KSEG0ADDR(buf), nbytes);
+	dma_cache_inv((unsigned long)buf, nbytes);
 	dp->dscr_cmd0 |= DSCR_CMD0_V;	/* Let it rip */
 	wmb(); /* drain writebuffer */
 	dma_cache_wback_inv((unsigned long)dp, sizeof(*dp));
 	ctp->chan_ptr->ddma_dbell = 0;
-	wmb(); /* force doorbell write out to dma engine */
 
 	/* Get next descriptor pointer. */
 	ctp->put_ptr = phys_to_virt(DSCR_GET_NXTPTR(dp->dscr_nxtptr));
diff --git linux-libre-5.4.255-gnu1/arch/powerpc/platforms/powermac/smp.c linux-libre-5.4.256-gnu1/arch/powerpc/platforms/powermac/smp.c
index f95fbdee6efe..d2900689d642 100644
--- linux-libre-5.4.255-gnu1/arch/powerpc/platforms/powermac/smp.c
+++ linux-libre-5.4.256-gnu1/arch/powerpc/platforms/powermac/smp.c
@@ -660,13 +660,13 @@ static void smp_core99_gpio_tb_freeze(int freeze)
 
 #endif /* !CONFIG_PPC64 */
 
-/* L2 and L3 cache settings to pass from CPU0 to CPU1 on G4 cpus */
-volatile static long int core99_l2_cache;
-volatile static long int core99_l3_cache;
-
 static void core99_init_caches(int cpu)
 {
 #ifndef CONFIG_PPC64
+	/* L2 and L3 cache settings to pass from CPU0 to CPU1 on G4 cpus */
+	static long int core99_l2_cache;
+	static long int core99_l3_cache;
+
 	if (!cpu_has_feature(CPU_FTR_L2CR))
 		return;
 
