[PATCH] [7/8] Implement true end_pfn_mapped for 32bit

Andi Kleen
2008-02-11T09:36:54Z

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. Needed for followup patches (in this case EFI)

Cc: ying.huang@intel.com

Signed-off-by: Andi Kleen <ak@suse.de>

---
arch/x86/mm/init_32.c | 5 +++++
include/asm-x86/page.h | 4 +++-
include/asm-x86/page_64.h | 1 -
3 files changed, 8 insertions(+), 2 deletions(-)

Index: linux/arch/x86/mm/init_32.c
===================================================================
--- linux.orig/arch/x86/mm/init_32.c
+++ linux/arch/x86/mm/init_32.c
@@ -50,6 +50,8 @@

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;

@@ -193,6 +195,7 @@ static void __init kernel_physical_mappi
set_pmd(pmd, pfn_pmd(pfn, prot));

pfn += PTRS_PER_PTE;
+ end_pfn_map = pfn;
continue;
}
pte = one_page_table_init(pmd);
@@ -207,6 +210,7 @@ static void __init kernel_physical_mappi

set_pte(pte, pfn_pte(pfn, prot));
}
+ end_pfn_map = pfn;
}
}
}
Index: linux/include/asm-x86/page.h
===================================================================
--- linux.orig/include/asm-x86/page.h
+++ linux/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)
@@ -51,6 +51,8 @@
extern int page_is_ram(unsigned long pagenr);
extern int devmem_is_allowed(unsigned long pagenr);

+extern unsigned long end_pfn_map;
+
struct page;

static void inline clear_user_page(void *page, unsigned long vaddr,
Index: linux/include/asm-x86/page_64.h
===================================================================
--- linux.orig/include/asm-x86/page_64.h
+++ linux/include/asm-x86/page_64.h
@@ -55,7 +55,6 @@ 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);