[PATCH V4 09/11] arm64: mm: Modify calculation of VMEMMAP_SIZE
From: Steve Capper <hidden>
Date: 2019-07-29 16:26:10
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
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 <redacted> --- arch/arm64/include/asm/memory.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index 93341f4fe840..aa7186006ee5 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
--
2.20.1
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