x86: implement true end_pfn_mapped for 32bit

Even on 32bit 2MB pages can map more memory than is in the true
max_low_pfn if end_pfn is not highmem and not aligned to 2MB.
Add a end_pfn_map similar to x86-64 that accounts for this
fact. This is important for code that really needs to know about
all mapping aliases.

Signed-off-by: Andi Kleen <ak@suse.de>
Cc: andreas.herrmann3@amd.com
Cc: mingo@elte.hu
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 3 insertions, 1 deletions

diff --git a/include/asm-x86/page.h b/include/asm-x86/page.h
index a05b2896492f..b734939916c4 100644
--- a/include/asm-x86/page.h
+++ b/include/asm-x86/page.h
@@ -36,7 +36,7 @@
 #define max_pfn_mapped          end_pfn_map
 #else
 #include <asm/page_32.h>
-#define max_pfn_mapped          max_low_pfn
+#define max_pfn_mapped          end_pfn_map
 #endif  /* CONFIG_X86_64 */
 
 #define PAGE_OFFSET             ((unsigned long)__PAGE_OFFSET)
@@ -50,6 +50,8 @@
 
 extern int page_is_ram(unsigned long pagenr);
 
+extern unsigned long end_pfn_map;
+
 struct page;
 
 static inline void clear_user_page(void *page, unsigned long vaddr,