x86, kexec, 64bit: Only set ident mapping for ram.

We should set mappings only for usable memory ranges under max_pfn
Otherwise causes same problem that is fixed by

	x86, mm: Only direct map addresses that are marked as E820_RAM

This patch exposes pfn_mapped array, and only sets ident mapping for ranges
in that array.

This patch relies on new kernel_ident_mapping_init that could handle existing
pgd/pud between different calls.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1359058816-7615-25-git-send-email-yinghai@kernel.org
Cc: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

3 files changed, 15 insertions, 6 deletions

diff --git a/arch/x86/include/asm/page.h b/arch/x86/include/asm/page.h
index 8ca82839288a..100a20c7b98d 100644
--- a/arch/x86/include/asm/page.h
+++ b/arch/x86/include/asm/page.h
@@ -17,6 +17,10 @@
 
 struct page;
 
+#include <linux/range.h>
+extern struct range pfn_mapped[];
+extern int nr_pfn_mapped;
+
 static inline void clear_user_page(void *page, unsigned long vaddr,
                                    struct page *pg)
 {
diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
index d2d7e023a8c8..4eabc160696f 100644
--- a/arch/x86/kernel/machine_kexec_64.c
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -100,10 +100,15 @@ static int init_pgtable(struct kimage *image, unsigned long start_pgtable)
 
         level4p = (pgd_t *)__va(start_pgtable);
         clear_page(level4p);
-        result = kernel_ident_mapping_init(&info, level4p,
-                                                0, max_pfn << PAGE_SHIFT);
-        if (result)
-                return result;
+        for (i = 0; i < nr_pfn_mapped; i++) {
+                mstart = pfn_mapped[i].start << PAGE_SHIFT;
+                mend   = pfn_mapped[i].end << PAGE_SHIFT;
+
+                result = kernel_ident_mapping_init(&info,
+                                                 level4p, mstart, mend);
+                if (result)
+                        return result;
+        }
 
         /*
          * segments's mem ranges could be outside 0 ~ max_pfn,
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 3364a7643a4c..d41815265a0b 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -302,8 +302,8 @@ static int __meminit split_mem_range(struct map_range *mr, int nr_range,
         return nr_range;
 }
 
-static struct range pfn_mapped[E820_X_MAX];
-static int nr_pfn_mapped;
+struct range pfn_mapped[E820_X_MAX];
+int nr_pfn_mapped;
 
 static void add_pfn_range_mapped(unsigned long start_pfn, unsigned long end_pfn)
 {