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authorKristina Martsenko <kristina.martsenko@arm.com>2017-12-13 17:07:18 +0000
committerCatalin Marinas <catalin.marinas@arm.com>2017-12-22 17:35:21 +0000
commit529c4b05a3cb2f324aac347042ee6d641478e946 (patch)
tree2fab0e91f3abe37f2b7ee29a02e0c41af6ad03d6 /arch/arm64/mm/pgd.c
parent787fd1d019b269af7912249231dfe34a5fe3e7c8 (diff)
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 <suzuki.poulose@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Tested-by: Bob Picco <bob.picco@oracle.com> Reviewed-by: Bob Picco <bob.picco@oracle.com> Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com> [catalin.marinas@arm.com: added TTBR_BADD_MASK_52 comment] Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/mm/pgd.c')
-rw-r--r--arch/arm64/mm/pgd.c8
1 files changed, 8 insertions, 0 deletions
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.
*/