arm64: mm: restrict virt_to_page() to the linear mapping

[cascardo/linux.git] / arch / arm64 / include / asm / memory.h

diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index 12f8a00..f412f50 100644 (file)
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -39,6 +39,21 @@
  */
 #define PCI_IO_SIZE            SZ_16M
 
+/*
+ * Log2 of the upper bound of the size of a struct page. Used for sizing
+ * the vmemmap region only, does not affect actual memory footprint.
+ * We don't use sizeof(struct page) directly since taking its size here
+ * requires its definition to be available at this point in the inclusion
+ * chain, and it may not be a power of 2 in the first place.
+ */
+#define STRUCT_PAGE_MAX_SHIFT  6
+
+/*
+ * VMEMMAP_SIZE - allows the whole linear region to be covered by
+ *                a struct page array
+ */
+#define VMEMMAP_SIZE (UL(1) << (VA_BITS - PAGE_SHIFT - 1 + STRUCT_PAGE_MAX_SHIFT))
+
 /*
  * PAGE_OFFSET - the virtual address of the start of the kernel image (top
  *              (VA_BITS - 1))
@@ -54,7 +69,8 @@
 #define MODULES_END            (MODULES_VADDR + MODULES_VSIZE)
 #define MODULES_VADDR          (VA_START + KASAN_SHADOW_SIZE)
 #define MODULES_VSIZE          (SZ_128M)
-#define PCI_IO_END             (PAGE_OFFSET - SZ_2M)
+#define VMEMMAP_START          (PAGE_OFFSET - VMEMMAP_SIZE)
+#define PCI_IO_END             (VMEMMAP_START - SZ_2M)
 #define PCI_IO_START           (PCI_IO_END - PCI_IO_SIZE)
 #define FIXADDR_TOP            (PCI_IO_START - SZ_2M)
 #define TASK_SIZE_64           (UL(1) << VA_BITS)
@@ -192,9 +208,19 @@ static inline void *phys_to_virt(phys_addr_t x)
  */
 #define ARCH_PFN_OFFSET                ((unsigned long)PHYS_PFN_OFFSET)
 
+#ifndef CONFIG_SPARSEMEM_VMEMMAP
 #define virt_to_page(kaddr)    pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)
-#define        virt_addr_valid(kaddr)  pfn_valid(__pa(kaddr) >> PAGE_SHIFT)
+#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)(page) & ~VMEMMAP_START) * PAGE_SIZE / sizeof(struct page))
 
+#define page_to_virt(page)     ((void *)((__page_to_voff(page)) | PAGE_OFFSET))
+#define virt_to_page(vaddr)    ((struct page *)((__virt_to_pgoff(vaddr)) | VMEMMAP_START))
+
+#define virt_addr_valid(kaddr) pfn_valid((((u64)(kaddr) & ~PAGE_OFFSET) \
+                                          + PHYS_OFFSET) >> PAGE_SHIFT)
+#endif
 #endif
 
 #include <asm-generic/memory_model.h>