diff --git a/arch/powerpc/include/asm/book3s/64/mmu.h b/arch/powerpc/include/asm/book3s/64/mmu.h
index c9448e19847a..27e7e9732ea1 100644
--- a/arch/powerpc/include/asm/book3s/64/mmu.h
+++ b/arch/powerpc/include/asm/book3s/64/mmu.h
@@ -91,7 +91,7 @@ typedef struct {
 	struct npu_context *npu_context;
 
 #ifdef CONFIG_PPC_MM_SLICES
-	u64 low_slices_psize;	/* SLB page size encodings */
+	unsigned char low_slices_psize[8]; /* SLB page size encodings */
 	unsigned char high_slices_psize[SLICE_ARRAY_SIZE];
 	unsigned long slb_addr_limit;
 #else
diff --git a/arch/powerpc/include/asm/mmu-8xx.h b/arch/powerpc/include/asm/mmu-8xx.h
index 5f89b6010453..d669d0062da4 100644
--- a/arch/powerpc/include/asm/mmu-8xx.h
+++ b/arch/powerpc/include/asm/mmu-8xx.h
@@ -171,7 +171,7 @@ typedef struct {
 	unsigned long vdso_base;
 #ifdef CONFIG_PPC_MM_SLICES
 	u16 user_psize;		/* page size index */
-	u64 low_slices_psize;	/* page size encodings */
+	unsigned char low_slices_psize[8]; /* 16 slices */
 	unsigned char high_slices_psize[0];
 	unsigned long slb_addr_limit;
 #endif
diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h
index 3892db93b837..612017054825 100644
--- a/arch/powerpc/include/asm/paca.h
+++ b/arch/powerpc/include/asm/paca.h
@@ -141,7 +141,7 @@ struct paca_struct {
 #ifdef CONFIG_PPC_BOOK3S
 	mm_context_id_t mm_ctx_id;
 #ifdef CONFIG_PPC_MM_SLICES
-	u64 mm_ctx_low_slices_psize;
+	unsigned char mm_ctx_low_slices_psize[8];
 	unsigned char mm_ctx_high_slices_psize[SLICE_ARRAY_SIZE];
 	unsigned long mm_ctx_slb_addr_limit;
 #else
diff --git a/arch/powerpc/kernel/paca.c b/arch/powerpc/kernel/paca.c
index d6597038931d..8e1566bf82b8 100644
--- a/arch/powerpc/kernel/paca.c
+++ b/arch/powerpc/kernel/paca.c
@@ -264,7 +264,8 @@ void copy_mm_to_paca(struct mm_struct *mm)
 #ifdef CONFIG_PPC_MM_SLICES
 	VM_BUG_ON(!mm->context.slb_addr_limit);
 	get_paca()->mm_ctx_slb_addr_limit = mm->context.slb_addr_limit;
-	get_paca()->mm_ctx_low_slices_psize = context->low_slices_psize;
+	memcpy(&get_paca()->mm_ctx_low_slices_psize,
+	       &context->low_slices_psize, sizeof(context->low_slices_psize));
 	memcpy(&get_paca()->mm_ctx_high_slices_psize,
 	       &context->high_slices_psize, TASK_SLICE_ARRAY_SZ(mm));
 #else /* CONFIG_PPC_MM_SLICES */
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 3266b3326088..2f0c6b527a83 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -1097,19 +1097,18 @@ unsigned int hash_page_do_lazy_icache(unsigned int pp, pte_t pte, int trap)
 #ifdef CONFIG_PPC_MM_SLICES
 static unsigned int get_paca_psize(unsigned long addr)
 {
-	u64 lpsizes;
-	unsigned char *hpsizes;
+	unsigned char *psizes;
 	unsigned long index, mask_index;
 
 	if (addr <= SLICE_LOW_TOP) {
-		lpsizes = get_paca()->mm_ctx_low_slices_psize;
+		psizes = get_paca()->mm_ctx_low_slices_psize;
 		index = GET_LOW_SLICE_INDEX(addr);
-		return (lpsizes >> (index * 4)) & 0xF;
+	} else {
+		psizes = get_paca()->mm_ctx_high_slices_psize;
+		index = GET_HIGH_SLICE_INDEX(addr);
 	}
-	hpsizes = get_paca()->mm_ctx_high_slices_psize;
-	index = GET_HIGH_SLICE_INDEX(addr);
 	mask_index = index & 0x1;
-	return (hpsizes[index >> 1] >> (mask_index * 4)) & 0xF;
+	return (psizes[index >> 1] >> (mask_index * 4)) & 0xF;
 }
 
 #else
diff --git a/arch/powerpc/mm/slb_low.S b/arch/powerpc/mm/slb_low.S
index 2cf5ef3fc50d..2c7c717fd2ea 100644
--- a/arch/powerpc/mm/slb_low.S
+++ b/arch/powerpc/mm/slb_low.S
@@ -200,10 +200,12 @@ END_MMU_FTR_SECTION_IFCLR(MMU_FTR_1T_SEGMENT)
 5:
 	/*
 	 * Handle lpsizes
-	 * r9 is get_paca()->context.low_slices_psize, r11 is index
+	 * r9 is get_paca()->context.low_slices_psize[index], r11 is mask_index
 	 */
-	ld	r9,PACALOWSLICESPSIZE(r13)
-	mr	r11,r10
+	srdi    r11,r10,1 /* index */
+	addi	r9,r11,PACALOWSLICESPSIZE
+	lbzx	r9,r13,r9		/* r9 is lpsizes[r11] */
+	rldicl	r11,r10,0,63		/* r11 = r10 & 0x1 */
 6:
 	sldi	r11,r11,2  /* index * 4 */
 	/* Extract the psize and multiply to get an array offset */
diff --git a/arch/powerpc/mm/slice.c b/arch/powerpc/mm/slice.c
index 1a66fafc3e45..e01ea72f21c6 100644
--- a/arch/powerpc/mm/slice.c
+++ b/arch/powerpc/mm/slice.c
@@ -43,7 +43,7 @@ static DEFINE_SPINLOCK(slice_convert_lock);
  * in 1TB size.
  */
 struct slice_mask {
-	u64 low_slices;
+	DECLARE_BITMAP(low_slices, SLICE_NUM_LOW);
 	DECLARE_BITMAP(high_slices, SLICE_NUM_HIGH);
 };
 
@@ -54,7 +54,8 @@ static void slice_print_mask(const char *label, struct slice_mask mask)
 {
 	if (!_slice_debug)
 		return;
-	pr_devel("%s low_slice: %*pbl\n", label, (int)SLICE_NUM_LOW, &mask.low_slices);
+	pr_devel("%s low_slice: %*pbl\n", label, (int)SLICE_NUM_LOW,
+		 mask.low_slices);
 	pr_devel("%s high_slice: %*pbl\n", label, (int)SLICE_NUM_HIGH, mask.high_slices);
 }
 
@@ -72,15 +73,18 @@ static void slice_range_to_mask(unsigned long start, unsigned long len,
 {
 	unsigned long end = start + len - 1;
 
-	ret->low_slices = 0;
+	bitmap_zero(ret->low_slices, SLICE_NUM_LOW);
 	if (SLICE_NUM_HIGH)
 		bitmap_zero(ret->high_slices, SLICE_NUM_HIGH);
 
 	if (start <= SLICE_LOW_TOP) {
 		unsigned long mend = min(end, SLICE_LOW_TOP);
+		unsigned long start_index = GET_LOW_SLICE_INDEX(start);
+		unsigned long align_end = ALIGN(mend, (1UL << SLICE_LOW_SHIFT));
+		unsigned long count = GET_LOW_SLICE_INDEX(align_end) -
+				      start_index;
 
-		ret->low_slices = (1u << (GET_LOW_SLICE_INDEX(mend) + 1))
-			- (1u << GET_LOW_SLICE_INDEX(start));
+		bitmap_set(ret->low_slices, start_index, count);
 	}
 
 	if ((start + len) > SLICE_LOW_TOP) {
@@ -128,13 +132,13 @@ static void slice_mask_for_free(struct mm_struct *mm, struct slice_mask *ret,
 {
 	unsigned long i;
 
-	ret->low_slices = 0;
+	bitmap_zero(ret->low_slices, SLICE_NUM_LOW);
 	if (SLICE_NUM_HIGH)
 		bitmap_zero(ret->high_slices, SLICE_NUM_HIGH);
 
 	for (i = 0; i < SLICE_NUM_LOW; i++)
 		if (!slice_low_has_vma(mm, i))
-			ret->low_slices |= 1u << i;
+			__set_bit(i, ret->low_slices);
 
 	if (high_limit <= SLICE_LOW_TOP)
 		return;
@@ -147,19 +151,21 @@ static void slice_mask_for_free(struct mm_struct *mm, struct slice_mask *ret,
 static void slice_mask_for_size(struct mm_struct *mm, int psize, struct slice_mask *ret,
 				unsigned long high_limit)
 {
-	unsigned char *hpsizes;
+	unsigned char *hpsizes, *lpsizes;
 	int index, mask_index;
 	unsigned long i;
-	u64 lpsizes;
 
-	ret->low_slices = 0;
+	bitmap_zero(ret->low_slices, SLICE_NUM_LOW);
 	if (SLICE_NUM_HIGH)
 		bitmap_zero(ret->high_slices, SLICE_NUM_HIGH);
 
 	lpsizes = mm->context.low_slices_psize;
-	for (i = 0; i < SLICE_NUM_LOW; i++)
-		if (((lpsizes >> (i * 4)) & 0xf) == psize)
-			ret->low_slices |= 1u << i;
+	for (i = 0; i < SLICE_NUM_LOW; i++) {
+		mask_index = i & 0x1;
+		index = i >> 1;
+		if (((lpsizes[index] >> (mask_index * 4)) & 0xf) == psize)
+			__set_bit(i, ret->low_slices);
+	}
 
 	if (high_limit <= SLICE_LOW_TOP)
 		return;
@@ -176,6 +182,7 @@ static void slice_mask_for_size(struct mm_struct *mm, int psize, struct slice_ma
 static int slice_check_fit(struct mm_struct *mm,
 			   struct slice_mask mask, struct slice_mask available)
 {
+	DECLARE_BITMAP(result_low, SLICE_NUM_LOW);
 	DECLARE_BITMAP(result, SLICE_NUM_HIGH);
 	/*
 	 * Make sure we just do bit compare only to the max
@@ -183,11 +190,13 @@ static int slice_check_fit(struct mm_struct *mm,
 	 */
 	unsigned long slice_count = GET_HIGH_SLICE_INDEX(mm->context.slb_addr_limit);
 
+	bitmap_and(result_low, mask.low_slices,
+		   available.low_slices, SLICE_NUM_LOW);
 	if (SLICE_NUM_HIGH)
 		bitmap_and(result, mask.high_slices,
 			   available.high_slices, slice_count);
 
-	return (mask.low_slices & available.low_slices) == mask.low_slices &&
+	return bitmap_equal(result_low, mask.low_slices, SLICE_NUM_LOW) &&
 		(!slice_count ||
 		 bitmap_equal(result, mask.high_slices, slice_count));
 }
@@ -213,8 +222,7 @@ static void slice_convert(struct mm_struct *mm, struct slice_mask mask, int psiz
 {
 	int index, mask_index;
 	/* Write the new slice psize bits */
-	unsigned char *hpsizes;
-	u64 lpsizes;
+	unsigned char *hpsizes, *lpsizes;
 	unsigned long i, flags;
 
 	slice_dbg("slice_convert(mm=%p, psize=%d)\n", mm, psize);
@@ -226,13 +234,14 @@ static void slice_convert(struct mm_struct *mm, struct slice_mask mask, int psiz
 	spin_lock_irqsave(&slice_convert_lock, flags);
 
 	lpsizes = mm->context.low_slices_psize;
-	for (i = 0; i < SLICE_NUM_LOW; i++)
-		if (mask.low_slices & (1u << i))
-			lpsizes = (lpsizes & ~(0xful << (i * 4))) |
-				(((unsigned long)psize) << (i * 4));
-
-	/* Assign the value back */
-	mm->context.low_slices_psize = lpsizes;
+	for (i = 0; i < SLICE_NUM_LOW; i++) {
+		mask_index = i & 0x1;
+		index = i >> 1;
+		if (test_bit(i, mask.low_slices))
+			lpsizes[index] = (lpsizes[index] &
+					  ~(0xf << (mask_index * 4))) |
+				(((unsigned long)psize) << (mask_index * 4));
+	}
 
 	hpsizes = mm->context.high_slices_psize;
 	for (i = 0; i < GET_HIGH_SLICE_INDEX(mm->context.slb_addr_limit); i++) {
@@ -269,7 +278,7 @@ static bool slice_scan_available(unsigned long addr,
 	if (addr <= SLICE_LOW_TOP) {
 		slice = GET_LOW_SLICE_INDEX(addr);
 		*boundary_addr = (slice + end) << SLICE_LOW_SHIFT;
-		return !!(available.low_slices & (1u << slice));
+		return !!test_bit(slice, available.low_slices);
 	} else {
 		slice = GET_HIGH_SLICE_INDEX(addr);
 		*boundary_addr = (slice + end) ?
@@ -397,7 +406,8 @@ static inline void slice_or_mask(struct slice_mask *dst, struct slice_mask *src)
 {
 	DECLARE_BITMAP(result, SLICE_NUM_HIGH);
 
-	dst->low_slices |= src->low_slices;
+	bitmap_or(dst->low_slices, dst->low_slices, src->low_slices,
+		  SLICE_NUM_LOW);
 	if (SLICE_NUM_HIGH) {
 		bitmap_or(result, dst->high_slices, src->high_slices,
 			  SLICE_NUM_HIGH);
@@ -409,7 +419,8 @@ static inline void slice_andnot_mask(struct slice_mask *dst, struct slice_mask *
 {
 	DECLARE_BITMAP(result, SLICE_NUM_HIGH);
 
-	dst->low_slices &= ~src->low_slices;
+	bitmap_andnot(dst->low_slices, dst->low_slices, src->low_slices,
+		      SLICE_NUM_LOW);
 
 	if (SLICE_NUM_HIGH) {
 		bitmap_andnot(result, dst->high_slices, src->high_slices,
@@ -464,16 +475,16 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
 	/*
 	 * init different masks
 	 */
-	mask.low_slices = 0;
+	bitmap_zero(mask.low_slices, SLICE_NUM_LOW);
 	if (SLICE_NUM_HIGH)
 		bitmap_zero(mask.high_slices, SLICE_NUM_HIGH);
 
 	/* silence stupid warning */;
-	potential_mask.low_slices = 0;
+	bitmap_zero(potential_mask.low_slices, SLICE_NUM_LOW);
 	if (SLICE_NUM_HIGH)
 		bitmap_zero(potential_mask.high_slices, SLICE_NUM_HIGH);
 
-	compat_mask.low_slices = 0;
+	bitmap_zero(compat_mask.low_slices, SLICE_NUM_LOW);
 	if (SLICE_NUM_HIGH)
 		bitmap_zero(compat_mask.high_slices, SLICE_NUM_HIGH);
 
@@ -613,7 +624,7 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
  convert:
 	slice_andnot_mask(&mask, &good_mask);
 	slice_andnot_mask(&mask, &compat_mask);
-	if (mask.low_slices ||
+	if (!bitmap_empty(mask.low_slices, SLICE_NUM_LOW) ||
 	    (SLICE_NUM_HIGH &&
 	     !bitmap_empty(mask.high_slices, SLICE_NUM_HIGH))) {
 		slice_convert(mm, mask, psize);
@@ -647,7 +658,7 @@ unsigned long arch_get_unmapped_area_topdown(struct file *filp,
 
 unsigned int get_slice_psize(struct mm_struct *mm, unsigned long addr)
 {
-	unsigned char *hpsizes;
+	unsigned char *psizes;
 	int index, mask_index;
 
 	/*
@@ -661,15 +672,14 @@ unsigned int get_slice_psize(struct mm_struct *mm, unsigned long addr)
 #endif
 	}
 	if (addr <= SLICE_LOW_TOP) {
-		u64 lpsizes;
-		lpsizes = mm->context.low_slices_psize;
+		psizes = mm->context.low_slices_psize;
 		index = GET_LOW_SLICE_INDEX(addr);
-		return (lpsizes >> (index * 4)) & 0xf;
+	} else {
+		psizes = mm->context.high_slices_psize;
+		index = GET_HIGH_SLICE_INDEX(addr);
 	}
-	hpsizes = mm->context.high_slices_psize;
-	index = GET_HIGH_SLICE_INDEX(addr);
 	mask_index = index & 0x1;
-	return (hpsizes[index >> 1] >> (mask_index * 4)) & 0xf;
+	return (psizes[index >> 1] >> (mask_index * 4)) & 0xf;
 }
 EXPORT_SYMBOL_GPL(get_slice_psize);
 
@@ -690,8 +700,8 @@ EXPORT_SYMBOL_GPL(get_slice_psize);
 void slice_set_user_psize(struct mm_struct *mm, unsigned int psize)
 {
 	int index, mask_index;
-	unsigned char *hpsizes;
-	unsigned long flags, lpsizes;
+	unsigned char *hpsizes, *lpsizes;
+	unsigned long flags;
 	unsigned int old_psize;
 	int i;
 
@@ -709,12 +719,14 @@ void slice_set_user_psize(struct mm_struct *mm, unsigned int psize)
 	wmb();
 
 	lpsizes = mm->context.low_slices_psize;
-	for (i = 0; i < SLICE_NUM_LOW; i++)
-		if (((lpsizes >> (i * 4)) & 0xf) == old_psize)
-			lpsizes = (lpsizes & ~(0xful << (i * 4))) |
-				(((unsigned long)psize) << (i * 4));
-	/* Assign the value back */
-	mm->context.low_slices_psize = lpsizes;
+	for (i = 0; i < SLICE_NUM_LOW; i++) {
+		mask_index = i & 0x1;
+		index = i >> 1;
+		if (((lpsizes[index] >> (mask_index * 4)) & 0xf) == old_psize)
+			lpsizes[index] = (lpsizes[index] &
+					  ~(0xf << (mask_index * 4))) |
+				(((unsigned long)psize) << (mask_index * 4));
+	}
 
 	hpsizes = mm->context.high_slices_psize;
 	for (i = 0; i < SLICE_NUM_HIGH; i++) {
