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-rw-r--r--arch/x86/mm/pgtable.c18
1 files changed, 18 insertions, 0 deletions
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index 86f2ffc43c3d..5b7c7c8464fe 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -313,6 +313,24 @@ int ptep_clear_flush_young(struct vm_area_struct *vma,
return young;
}
+/**
+ * reserve_top_address - reserves a hole in the top of kernel address space
+ * @reserve - size of hole to reserve
+ *
+ * Can be used to relocate the fixmap area and poke a hole in the top
+ * of kernel address space to make room for a hypervisor.
+ */
+void __init reserve_top_address(unsigned long reserve)
+{
+#ifdef CONFIG_X86_32
+ BUG_ON(fixmaps_set > 0);
+ printk(KERN_INFO "Reserving virtual address space above 0x%08x\n",
+ (int)-reserve);
+ __FIXADDR_TOP = -reserve - PAGE_SIZE;
+ __VMALLOC_RESERVE += reserve;
+#endif
+}
+
int fixmaps_set;
void __native_set_fixmap(enum fixed_addresses idx, pte_t pte)