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| author |   Steve Capper <steve.capper@arm.com> | 2019-08-07 16:55:21 +0100 |
|---|---|---|
| committer |   Will Deacon <will@kernel.org> | 2019-08-09 11:17:26 +0100 |
| commit | ce3aaed87344c83c77135f80e7b76e1da9c92ee6 (patch) | |
| tree | e6d129a82c0262b52d14d15e30a6fa5dd74a2f12 /arch | |
| parent | arm64: mm: Separate out vmemmap (diff) | |
| download | linux-dev-ce3aaed87344c83c77135f80e7b76e1da9c92ee6.tar.xz linux-dev-ce3aaed87344c83c77135f80e7b76e1da9c92ee6.zip | |
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 <steve.capper@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm64/include/asm/memory.h | 9 |
1 files changed, 8 insertions, 1 deletions
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 |