[PATCH 17/17] arm64/mm: Make ARM64_D128 selectable

[Anshuman Khandual <anshuman.khandual@arm.com>]

All required changes are already in place including the TLBIP instruction
support for enabling D128 translation. Just make this new ARM64_D128 user
selectable, after ensuring necessary tools chain support required for the
new instructions being used for D128.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
 arch/arm64/Kconfig | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 8459d43afd45..6c88906d48ec 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -275,6 +275,10 @@ config GCC_SUPPORTS_DYNAMIC_FTRACE_WITH_ARGS
 	def_bool CC_IS_GCC
 	depends on $(cc-option,-fpatchable-function-entry=2)
 
+config CC_SUPPORTS_LSE128
+	def_bool CC_IS_GCC
+	depends on $(cc-option, -march=armv8.1-a+lse128)
+
 config 64BIT
 	def_bool y
 
@@ -2249,8 +2253,18 @@ endmenu # "ARMv8.9 architectural features"
 
 menu "ARMv9.3 architectural features"
 
+config AS_HAS_ARMV9_3
+	def_bool $(cc-option,-Wa$(comma)-march=armv9.3-a)
+
 config ARM64_D128
-	bool
+	bool "Enable support for 128 bit page table (FEAT_D128)"
+	depends on ARCH_SUPPORTS_INT128
+	depends on CC_SUPPORTS_LSE128
+	depends on AS_HAS_ARMV9_3
+	depends on EXPERT
+	depends on !VIRTUALIZATION
+	depends on !KASAN
+	depends on !UNMAP_KERNEL_AT_EL0
 	default n
 	help
 	  ARMv9.3 introduces FEAT_D128, which provides a 128 bit page
-- 
2.43.0