From 529c4b05a3cb2f324aac347042ee6d641478e946 Mon Sep 17 00:00:00 2001 From: Kristina Martsenko Date: Wed, 13 Dec 2017 17:07:18 +0000 Subject: arm64: handle 52-bit addresses in TTBR The top 4 bits of a 52-bit physical address are positioned at bits 2..5 in the TTBR registers. Introduce a couple of macros to move the bits there, and change all TTBR writers to use them. Leave TTBR0 PAN code unchanged, to avoid complicating it. A system with 52-bit PA will have PAN anyway (because it's ARMv8.1 or later), and a system without 52-bit PA can only use up to 48-bit PAs. A later patch in this series will add a kconfig dependency to ensure PAN is configured. In addition, when using 52-bit PA there is a special alignment requirement on the top-level table. We don't currently have any VA_BITS configuration that would violate the requirement, but one could be added in the future, so add a compile-time BUG_ON to check for it. Tested-by: Suzuki K Poulose Reviewed-by: Suzuki K Poulose Reviewed-by: Marc Zyngier Tested-by: Bob Picco Reviewed-by: Bob Picco Signed-off-by: Kristina Martsenko [catalin.marinas@arm.com: added TTBR_BADD_MASK_52 comment] Signed-off-by: Catalin Marinas --- arch/arm64/mm/pgd.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'arch/arm64/mm/pgd.c') diff --git a/arch/arm64/mm/pgd.c b/arch/arm64/mm/pgd.c index 051e71ec3335..289f9113a27a 100644 --- a/arch/arm64/mm/pgd.c +++ b/arch/arm64/mm/pgd.c @@ -49,6 +49,14 @@ void __init pgd_cache_init(void) if (PGD_SIZE == PAGE_SIZE) return; +#ifdef CONFIG_ARM64_PA_BITS_52 + /* + * With 52-bit physical addresses, the architecture requires the + * top-level table to be aligned to at least 64 bytes. + */ + BUILD_BUG_ON(PGD_SIZE < 64); +#endif + /* * Naturally aligned pgds required by the architecture. */ -- cgit v1.2.3