6 files changed, 51 insertions, 6 deletions

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 13b51a0c4e7f..854166422c42 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -173,7 +173,8 @@ config PGTABLE_LEVELS
         default 2 if ARM64_64K_PAGES && ARM64_VA_BITS_42
         default 3 if ARM64_64K_PAGES && ARM64_VA_BITS_48
         default 3 if ARM64_4K_PAGES && ARM64_VA_BITS_39
-        default 4 if ARM64_4K_PAGES && ARM64_VA_BITS_48
+        default 3 if ARM64_16K_PAGES && ARM64_VA_BITS_47
+        default 4 if !ARM64_64K_PAGES && ARM64_VA_BITS_48
 
 source "init/Kconfig"
 
@@ -363,6 +364,13 @@ config ARM64_4K_PAGES
         help
           This feature enables 4KB pages support.
 
+config ARM64_16K_PAGES
+        bool "16KB"
+        help
+          The system will use 16KB pages support. AArch32 emulation
+          requires applications compiled with 16K (or a multiple of 16K)
+          aligned segments.
+
 config ARM64_64K_PAGES
         bool "64KB"
         help
@@ -376,6 +384,7 @@ endchoice
 choice
         prompt "Virtual address space size"
         default ARM64_VA_BITS_39 if ARM64_4K_PAGES
+        default ARM64_VA_BITS_47 if ARM64_16K_PAGES
         default ARM64_VA_BITS_42 if ARM64_64K_PAGES
         help
           Allows choosing one of multiple possible virtual address
@@ -390,6 +399,10 @@ config ARM64_VA_BITS_42
         bool "42-bit"
         depends on ARM64_64K_PAGES
 
+config ARM64_VA_BITS_47
+        bool "47-bit"
+        depends on ARM64_16K_PAGES
+
 config ARM64_VA_BITS_48
         bool "48-bit"
 
@@ -399,6 +412,7 @@ config ARM64_VA_BITS
         int
         default 39 if ARM64_VA_BITS_39
         default 42 if ARM64_VA_BITS_42
+        default 47 if ARM64_VA_BITS_47
         default 48 if ARM64_VA_BITS_48
 
 config CPU_BIG_ENDIAN
@@ -466,7 +480,7 @@ config ARCH_WANT_GENERAL_HUGETLB
         def_bool y
 
 config ARCH_WANT_HUGE_PMD_SHARE
-        def_bool y if ARM64_4K_PAGES
+        def_bool y if ARM64_4K_PAGES || ARM64_16K_PAGES
 
 config HAVE_ARCH_TRANSPARENT_HUGEPAGE
         def_bool y
@@ -503,7 +517,25 @@ config XEN
 config FORCE_MAX_ZONEORDER
         int
         default "14" if (ARM64_64K_PAGES && TRANSPARENT_HUGEPAGE)
+        default "12" if (ARM64_16K_PAGES && TRANSPARENT_HUGEPAGE)
         default "11"
+        help
+          The kernel memory allocator divides physically contiguous memory
+          blocks into "zones", where each zone is a power of two number of
+          pages.  This option selects the largest power of two that the kernel
+          keeps in the memory allocator.  If you need to allocate very large
+          blocks of physically contiguous memory, then you may need to
+          increase this value.
+
+          This config option is actually maximum order plus one. For example,
+          a value of 11 means that the largest free memory block is 2^10 pages.
+
+          We make sure that we can allocate upto a HugePage size for each configuration.
+          Hence we have :
+                MAX_ORDER = (PMD_SHIFT - PAGE_SHIFT) + 1 => PAGE_SHIFT - 2
+
+          However for 4K, we choose a higher default value, 11 as opposed to 10, giving us
+          4M allocations matching the default size used by generic code.
 
 menuconfig ARMV8_DEPRECATED
         bool "Emulate deprecated/obsolete ARMv8 instructions"
@@ -689,9 +721,9 @@ config COMPAT
           the user helper functions, VFP support and the ptrace interface are
           handled appropriately by the kernel.
 
-          If you also enabled CONFIG_ARM64_64K_PAGES, please be aware that you
-          will only be able to execute AArch32 binaries that were compiled with
-          64k aligned segments.
+          If you use a page size other than 4KB (i.e, 16KB or 64KB), please be aware
+          that you will only be able to execute AArch32 binaries that were compiled
+          with page size aligned segments.
 
           If you want to execute 32-bit userspace applications, say Y.
 
diff --git a/arch/arm64/include/asm/page.h b/arch/arm64/include/asm/page.h
index da3235494ffd..9b2f5a9d019d 100644
--- a/arch/arm64/include/asm/page.h
+++ b/arch/arm64/include/asm/page.h
@@ -24,6 +24,9 @@
 #ifdef CONFIG_ARM64_64K_PAGES
 #define PAGE_SHIFT              16
 #define CONT_SHIFT              5
+#elif defined(CONFIG_ARM64_16K_PAGES)
+#define PAGE_SHIFT              14
+#define CONT_SHIFT              7
 #else
 #define PAGE_SHIFT              12
 #define CONT_SHIFT              4
diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index d59cb231a673..4b57e1080538 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -59,6 +59,9 @@
 #if defined(CONFIG_ARM64_4K_PAGES)
 #define ID_AA64MMFR0_TGRAN_SHIFT        ID_AA64MMFR0_TGRAN4_SHIFT
 #define ID_AA64MMFR0_TGRAN_SUPPORTED    ID_AA64MMFR0_TGRAN4_SUPPORTED
+#elif defined(CONFIG_ARM64_16K_PAGES)
+#define ID_AA64MMFR0_TGRAN_SHIFT        ID_AA64MMFR0_TGRAN16_SHIFT
+#define ID_AA64MMFR0_TGRAN_SUPPORTED    ID_AA64MMFR0_TGRAN16_SUPPORTED
 #elif defined(CONFIG_ARM64_64K_PAGES)
 #define ID_AA64MMFR0_TGRAN_SHIFT        ID_AA64MMFR0_TGRAN64_SHIFT
 #define ID_AA64MMFR0_TGRAN_SUPPORTED    ID_AA64MMFR0_TGRAN64_SUPPORTED
diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
index 5eac6a2300af..90c7ff233735 100644
--- a/arch/arm64/include/asm/thread_info.h
+++ b/arch/arm64/include/asm/thread_info.h
@@ -25,6 +25,8 @@
 
 #ifdef CONFIG_ARM64_4K_PAGES
 #define THREAD_SIZE_ORDER       2
+#elif defined(CONFIG_ARM64_16K_PAGES)
+#define THREAD_SIZE_ORDER       0
 #endif
 
 #define THREAD_SIZE             16384
diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig
index 5c7e920e4861..6a7d5cd772e6 100644
--- a/arch/arm64/kvm/Kconfig
+++ b/arch/arm64/kvm/Kconfig
@@ -19,6 +19,7 @@ if VIRTUALIZATION
 config KVM
         bool "Kernel-based Virtual Machine (KVM) support"
         depends on OF
+        depends on !ARM64_16K_PAGES
         select MMU_NOTIFIER
         select PREEMPT_NOTIFIERS
         select ANON_INODES
@@ -33,6 +34,8 @@ config KVM
         select HAVE_KVM_IRQFD
         ---help---
           Support hosting virtualized guest machines.
+          We don't support KVM with 16K page tables yet, due to the multiple
+          levels of fake page tables.
 
           If unsure, say N.
 
diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S
index 91cb2eaac256..3a4b8b19978b 100644
--- a/arch/arm64/mm/proc.S
+++ b/arch/arm64/mm/proc.S
@@ -30,7 +30,9 @@
 
 #ifdef CONFIG_ARM64_64K_PAGES
 #define TCR_TG_FLAGS    TCR_TG0_64K | TCR_TG1_64K
-#else
+#elif defined(CONFIG_ARM64_16K_PAGES)
+#define TCR_TG_FLAGS    TCR_TG0_16K | TCR_TG1_16K
+#else /* CONFIG_ARM64_4K_PAGES */
 #define TCR_TG_FLAGS    TCR_TG0_4K | TCR_TG1_4K
 #endif