From ce3aaed87344c83c77135f80e7b76e1da9c92ee6 Mon Sep 17 00:00:00 2001 From: Steve Capper Date: Wed, 7 Aug 2019 16:55:21 +0100 Subject: arm64: mm: Modify calculation of VMEMMAP_SIZE In a later patch we will need to have a slightly larger VMEMMAP region to accommodate boot time selection between 48/52-bit kernel VAs. This patch modifies the formula for computing VMEMMAP_SIZE to depend explicitly on the PAGE_OFFSET and start of kernel addressable memory. (This allows for a slightly larger direct linear map in future). Signed-off-by: Steve Capper Reviewed-by: Catalin Marinas Signed-off-by: Will Deacon --- arch/arm64/include/asm/memory.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'arch/arm64/include') diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h index 364635b8370a..0204c2006c92 100644 --- a/arch/arm64/include/asm/memory.h +++ b/arch/arm64/include/asm/memory.h @@ -26,8 +26,15 @@ /* * VMEMMAP_SIZE - allows the whole linear region to be covered by * a struct page array + * + * If we are configured with a 52-bit kernel VA then our VMEMMAP_SIZE + * neads to cover the memory region from the beginning of the 52-bit + * PAGE_OFFSET all the way to VA_START for 48-bit. This allows us to + * keep a constant PAGE_OFFSET and "fallback" to using the higher end + * of the VMEMMAP where 52-bit support is not available in hardware. */ -#define VMEMMAP_SIZE (UL(1) << (VA_BITS - PAGE_SHIFT - 1 + STRUCT_PAGE_MAX_SHIFT)) +#define VMEMMAP_SIZE ((_VA_START(VA_BITS_MIN) - PAGE_OFFSET) \ + >> (PAGE_SHIFT - STRUCT_PAGE_MAX_SHIFT)) /* * PAGE_OFFSET - the virtual address of the start of the linear map (top -- cgit v1.2.3