Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 fix from Will Deacon:
 "Arm64 fix for -rc7.  Without it, our struct page array can overflow
  the vmemmap region on systems with a large PHYS_OFFSET.

  Nothing else on the radar at the moment, so hopefully that's it for
  4.5 from us.

  Summary: Ensure struct page array fits within vmemmap area"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: vmemmap: use virtual projection of linear region

arch/arm64/include/asm/pgtable.h

@@ -34,13 +34,13 @@
 /*
  * VMALLOC and SPARSEMEM_VMEMMAP ranges.
  *
- * VMEMAP_SIZE: allows the whole VA space to be covered by a struct page array
+ * VMEMAP_SIZE: allows the whole linear region to be covered by a struct page array
  *	(rounded up to PUD_SIZE).
  * VMALLOC_START: beginning of the kernel VA space
  * VMALLOC_END: extends to the available space below vmmemmap, PCI I/O space,
  *	fixed mappings and modules
  */
-#define VMEMMAP_SIZE		ALIGN((1UL << (VA_BITS - PAGE_SHIFT)) * sizeof(struct page), PUD_SIZE)
+#define VMEMMAP_SIZE		ALIGN((1UL << (VA_BITS - PAGE_SHIFT - 1)) * sizeof(struct page), PUD_SIZE)
 
 #ifndef CONFIG_KASAN
 #define VMALLOC_START		(VA_START)
@@ -51,7 +51,8 @@
 
 #define VMALLOC_END		(PAGE_OFFSET - PUD_SIZE - VMEMMAP_SIZE - SZ_64K)
 
-#define vmemmap			((struct page *)(VMALLOC_END + SZ_64K))
+#define VMEMMAP_START		(VMALLOC_END + SZ_64K)
+#define vmemmap			((struct page *)VMEMMAP_START - (memstart_addr >> PAGE_SHIFT))
 
 #define FIRST_USER_ADDRESS	0UL
 

arch/arm64/mm/init.c

@@ -319,8 +319,8 @@ void __init mem_init(void)
 #endif
 		  MLG(VMALLOC_START, VMALLOC_END),
 #ifdef CONFIG_SPARSEMEM_VMEMMAP
-		  MLG((unsigned long)vmemmap,
-		      (unsigned long)vmemmap + VMEMMAP_SIZE),
+		  MLG(VMEMMAP_START,
+		      VMEMMAP_START + VMEMMAP_SIZE),
 		  MLM((unsigned long)virt_to_page(PAGE_OFFSET),
 		      (unsigned long)virt_to_page(high_memory)),
 #endif