From mboxrd@z Thu Jan 1 00:00:00 1970 From: suzuki.poulose@arm.com (Suzuki K. Poulose) Date: Tue, 15 Sep 2015 16:41:24 +0100 Subject: [PATCH 15/15] arm64: 36 bit VA In-Reply-To: <1442331684-28818-1-git-send-email-suzuki.poulose@arm.com> References: <1442331684-28818-1-git-send-email-suzuki.poulose@arm.com> Message-ID: <1442331684-28818-16-git-send-email-suzuki.poulose@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org From: "Suzuki K. Poulose" 36bit VA lets us use 2 level page tables while limiting the available address space to 64GB. Cc: Mark Rutland Cc: Catalin Marinas Cc: Will Deacon Signed-off-by: Suzuki K. Poulose Reviewed-by: Ard Biesheuvel Tested-by: Ard Biesheuvel --- arch/arm64/Kconfig | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 2253819..3560241 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -168,6 +168,7 @@ config FIX_EARLYCON_MEM config PGTABLE_LEVELS int + default 2 if ARM64_16K_PAGES && ARM64_VA_BITS_36 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 @@ -373,6 +374,10 @@ choice space sizes. The level of translation table is determined by a combination of page size and virtual address space size. +config ARM64_VA_BITS_36 + bool "36-bit" + depends on ARM64_16K_PAGES + config ARM64_VA_BITS_39 bool "39-bit" depends on ARM64_4K_PAGES @@ -392,6 +397,7 @@ endchoice config ARM64_VA_BITS int + default 36 if ARM64_VA_BITS_36 default 39 if ARM64_VA_BITS_39 default 42 if ARM64_VA_BITS_42 default 47 if ARM64_VA_BITS_47 @@ -465,7 +471,7 @@ config ARCH_WANT_GENERAL_HUGETLB def_bool y config ARCH_WANT_HUGE_PMD_SHARE - def_bool y if ARM64_4K_PAGES || ARM64_16K_PAGES + def_bool y if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36) config HAVE_ARCH_TRANSPARENT_HUGEPAGE def_bool y -- 1.7.9.5