ARC: Fix PAE40 boot failures due to PTE truncation

[deliverable/linux.git] / arch / arc / include / asm / page.h

diff --git a/arch/arc/include/asm/page.h b/arch/arc/include/asm/page.h
index 36da89e2c853ef0551bfcee0f145454e23a81dd6..533e5a0c6ba52cdc458a33f9d678d9f9a62c1bce 100644 (file)
--- a/arch/arc/include/asm/page.h
+++ b/arch/arc/include/asm/page.h
@@ -72,6 +72,13 @@ typedef unsigned long pgprot_t;
 
 typedef pte_t * pgtable_t;
 
+/*
+ * Use virt_to_pfn with caution:
+ * If used in pte or paddr related macros, it could cause truncation
+ * in PAE40 builds
+ * As a rule of thumb, only use it in helpers starting with virt_
+ * You have been warned !
+ */
 #define virt_to_pfn(kaddr)     (__pa(kaddr) >> PAGE_SHIFT)
 
 #define ARCH_PFN_OFFSET                virt_to_pfn(CONFIG_LINUX_LINK_BASE)
@@ -85,7 +92,7 @@ typedef pte_t * pgtable_t;
  * virt here means link-address/program-address as embedded in object code.
  * And for ARC, link-addr = physical address
  */
-#define __pa(vaddr)  ((unsigned long)vaddr)
+#define __pa(vaddr)  ((unsigned long)(vaddr))
 #define __va(paddr)  ((void *)((unsigned long)(paddr)))
 
 #define virt_to_page(kaddr)    \