@@ -37,8 +37,15 @@
/*
* 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
@@ -319,7 +326,7 @@ static inline void *phys_to_virt(phys_addr_t x)
#define _virt_addr_valid(kaddr) pfn_valid(__pa(kaddr) >> PAGE_SHIFT)
#else
#define __virt_to_pgoff(kaddr) (((u64)(kaddr) & ~PAGE_OFFSET) / PAGE_SIZE * sizeof(struct page))
-#define __page_to_voff(kaddr) (((u64)(kaddr) & ~VMEMMAP_START) * PAGE_SIZE / sizeof(struct page))
+#define __page_to_voff(kaddr) (((u64)(kaddr) - VMEMMAP_START) * PAGE_SIZE / sizeof(struct page))
#define page_to_virt(page) ({ \
unsigned long __addr = \
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). Also this patch removes the use of bitmasking in the computation of _page_to_voff as this can cause problems if we decide to move regions around in future. Signed-off-by: Steve Capper <steve.capper@arm.com> --- arch/arm64/include/asm/memory.h | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)