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 <[email protected]> Cc: [email protected] Cc: [email protected] Signed-off-by: Thomas Gleixner <[email protected]> Signed-off-by: Ingo Molnar <[email protected]>
tdeneau · Apr 17, 2008 · 7d1116a · 7d1116a
1 parent 41bd4ea
commit 7d1116a
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Showing 3 changed files with 7 additions and 2 deletions.
diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
@@ -51,6 +51,8 @@
 
 unsigned int __VMALLOC_RESERVE = 128 << 20;
 
+unsigned long end_pfn_map;
+
 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
 unsigned long highstart_pfn, highend_pfn;
 
@@ -194,6 +196,7 @@ static void __init kernel_physical_mapping_init(pgd_t *pgd_base)
 				set_pmd(pmd, pfn_pmd(pfn, prot));
 
 				pfn += PTRS_PER_PTE;
+				end_pfn_map = pfn;
 				continue;
 			}
 			pte = one_page_table_init(pmd);
@@ -208,6 +211,7 @@ static void __init kernel_physical_mapping_init(pgd_t *pgd_base)
 
 				set_pte(pte, pfn_pte(pfn, prot));
 			}
+			end_pfn_map = pfn;
 		}
 	}
 }

diff --git 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,

diff --git a/include/asm-x86/page_64.h b/include/asm-x86/page_64.h
@@ -59,7 +59,6 @@ void clear_page(void *page);
 void copy_page(void *to, void *from);
 
 extern unsigned long end_pfn;
-extern unsigned long end_pfn_map;
 extern unsigned long phys_base;
 
 extern unsigned long __phys_addr(unsigned long);