diff --git a/arch/powerpc/include/asm/book3s/64/hash-4k.h b/arch/powerpc/include/asm/book3s/64/hash-4k.h
index cf5ba5254299..54fab723a8c7 100644
--- a/arch/powerpc/include/asm/book3s/64/hash-4k.h
+++ b/arch/powerpc/include/asm/book3s/64/hash-4k.h
@@ -2,10 +2,10 @@
 #ifndef _ASM_POWERPC_BOOK3S_64_HASH_4K_H
 #define _ASM_POWERPC_BOOK3S_64_HASH_4K_H
 
-#define H_PTE_INDEX_SIZE  9
-#define H_PMD_INDEX_SIZE  7
-#define H_PUD_INDEX_SIZE  9
-#define H_PGD_INDEX_SIZE  9
+#define H_PTE_INDEX_SIZE  9  // size: 8B << 9 = 4KB, maps: 2^9 x   4KB =   2MB
+#define H_PMD_INDEX_SIZE  7  // size: 8B << 7 = 1KB, maps: 2^7 x   2MB = 256MB
+#define H_PUD_INDEX_SIZE  9  // size: 8B << 9 = 4KB, maps: 2^9 x 256MB = 128GB
+#define H_PGD_INDEX_SIZE  9  // size: 8B << 9 = 4KB, maps: 2^9 x 128GB =  64TB
 
 /*
  * Each context is 512TB. But on 4k we restrict our max TASK size to 64TB
diff --git a/arch/powerpc/include/asm/book3s/64/hash-64k.h b/arch/powerpc/include/asm/book3s/64/hash-64k.h
index f82ee8a3b561..81f4eb6e7da4 100644
--- a/arch/powerpc/include/asm/book3s/64/hash-64k.h
+++ b/arch/powerpc/include/asm/book3s/64/hash-64k.h
@@ -2,10 +2,11 @@
 #ifndef _ASM_POWERPC_BOOK3S_64_HASH_64K_H
 #define _ASM_POWERPC_BOOK3S_64_HASH_64K_H
 
-#define H_PTE_INDEX_SIZE  8
-#define H_PMD_INDEX_SIZE  10
-#define H_PUD_INDEX_SIZE  10
-#define H_PGD_INDEX_SIZE  8
+#define H_PTE_INDEX_SIZE   8  // size: 8B <<  8 = 2KB, maps 2^8  x 64KB = 16MB
+#define H_PMD_INDEX_SIZE  10  // size: 8B << 10 = 8KB, maps 2^10 x 16MB = 16GB
+#define H_PUD_INDEX_SIZE  10  // size: 8B << 10 = 8KB, maps 2^10 x 16GB = 16TB
+#define H_PGD_INDEX_SIZE   8  // size: 8B <<  8 = 2KB, maps 2^8  x 16TB =  4PB
+
 
 /*
  * Each context is 512TB size. SLB miss for first context/default context
diff --git a/arch/powerpc/include/asm/book3s/64/radix-4k.h b/arch/powerpc/include/asm/book3s/64/radix-4k.h
index 863c3e8286fb..d5f5ab73dc7f 100644
--- a/arch/powerpc/include/asm/book3s/64/radix-4k.h
+++ b/arch/powerpc/include/asm/book3s/64/radix-4k.h
@@ -5,10 +5,11 @@
 /*
  * For 4K page size supported index is 13/9/9/9
  */
-#define RADIX_PTE_INDEX_SIZE  9  /* 2MB huge page */
-#define RADIX_PMD_INDEX_SIZE  9  /* 1G huge page */
-#define RADIX_PUD_INDEX_SIZE	 9
-#define RADIX_PGD_INDEX_SIZE  13
+#define RADIX_PTE_INDEX_SIZE   9  // size: 8B <<  9 =  4KB, maps 2^9  x    4K =   2MB
+#define RADIX_PMD_INDEX_SIZE   9  // size: 8B <<  9 =  4KB, maps 2^9  x   2MB =   1GB
+#define RADIX_PUD_INDEX_SIZE   9  // size: 8B <<  9 =  4KB, maps 2^9  x   1GB = 512GB
+#define RADIX_PGD_INDEX_SIZE  13  // size: 8B << 13 = 64KB, maps 2^13 x 512GB =   4PB
+
 /*
  * One fragment per per page
  */
diff --git a/arch/powerpc/include/asm/book3s/64/radix-64k.h b/arch/powerpc/include/asm/book3s/64/radix-64k.h
index ccb78ca9d0c5..54e33828b0fb 100644
--- a/arch/powerpc/include/asm/book3s/64/radix-64k.h
+++ b/arch/powerpc/include/asm/book3s/64/radix-64k.h
@@ -5,10 +5,10 @@
 /*
  * For 64K page size supported index is 13/9/9/5
  */
-#define RADIX_PTE_INDEX_SIZE  5  /* 2MB huge page */
-#define RADIX_PMD_INDEX_SIZE  9  /* 1G huge page */
-#define RADIX_PUD_INDEX_SIZE	 9
-#define RADIX_PGD_INDEX_SIZE  13
+#define RADIX_PTE_INDEX_SIZE   5  // size: 8B <<  5 = 256B, maps 2^5  x   64K =   2MB
+#define RADIX_PMD_INDEX_SIZE   9  // size: 8B <<  9 =  4KB, maps 2^9  x   2MB =   1GB
+#define RADIX_PUD_INDEX_SIZE   9  // size: 8B <<  9 =  4KB, maps 2^9  x   1GB = 512GB
+#define RADIX_PGD_INDEX_SIZE  13  // size: 8B << 13 = 64KB, maps 2^13 x 512GB =   4PB
 
 /*
  * We use a 256 byte PTE page fragment in radix