x86, kexec: Set ident mapping for kernel that is above max_pfn

When first kernel is booted with memmap= or mem=  to limit max_pfn.
kexec can load second kernel above that max_pfn.

We need to set ident mapping for whole image in this case instead of just
for first 2M.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1359058816-7615-23-git-send-email-yinghai@kernel.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 37 insertions, 6 deletions

diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
index b3ea9db39db6..be14ee120c43 100644
--- a/arch/x86/kernel/machine_kexec_64.c
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -56,6 +56,25 @@ out:
         return result;
 }
 
+static int ident_mapping_init(struct kimage *image, pgd_t *level4p,
+                                unsigned long mstart, unsigned long mend)
+{
+        int result;
+
+        mstart = round_down(mstart, PMD_SIZE);
+        mend   = round_up(mend - 1, PMD_SIZE);
+
+        while (mstart < mend) {
+                result = init_one_level2_page(image, level4p, mstart);
+                if (result)
+                        return result;
+
+                mstart += PMD_SIZE;
+        }
+
+        return 0;
+}
+
 static void init_level2_page(pmd_t *level2p, unsigned long addr)
 {
         unsigned long end_addr;
@@ -184,22 +203,34 @@ err:
         return result;
 }
 
-
 static int init_pgtable(struct kimage *image, unsigned long start_pgtable)
 {
+        unsigned long mstart, mend;
         pgd_t *level4p;
         int result;
+        int i;
+
         level4p = (pgd_t *)__va(start_pgtable);
         result = init_level4_page(image, level4p, 0, max_pfn << PAGE_SHIFT);
         if (result)
                 return result;
+
         /*
-         * image->start may be outside 0 ~ max_pfn, for example when
-         * jump back to original kernel from kexeced kernel
+         * segments's mem ranges could be outside 0 ~ max_pfn,
+         * for example when jump back to original kernel from kexeced kernel.
+         * or first kernel is booted with user mem map, and second kernel
+         * could be loaded out of that range.
          */
-        result = init_one_level2_page(image, level4p, image->start);
-        if (result)
-                return result;
+        for (i = 0; i < image->nr_segments; i++) {
+                mstart = image->segment[i].mem;
+                mend   = mstart + image->segment[i].memsz;
+
+                result = ident_mapping_init(image, level4p, mstart, mend);
+
+                if (result)
+                        return result;
+        }
+
         return init_transition_pgtable(image, level4p);
 }