3 files changed, 40 insertions, 0 deletions

diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index d4b6e6a29ae3..c818b45bd07d 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -150,6 +150,12 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
                 return (__force void __iomem *)phys_to_virt(phys_addr);
 
         /*
+         * Check if the request spans more than any BAR in the iomem resource
+         * tree.
+         */
+        WARN_ON(iomem_map_sanity_check(phys_addr, size));
+
+        /*
          * Don't allow anybody to remap normal RAM that we're using..
          */
         for (pfn = phys_addr >> PAGE_SHIFT;
diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index fded376b94e3..01712cf1a38b 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -169,6 +169,7 @@ extern struct resource * __devm_request_region(struct device *dev,
 
 extern void __devm_release_region(struct device *dev, struct resource *parent,
                                   resource_size_t start, resource_size_t n);
+extern int iomem_map_sanity_check(resource_size_t addr, unsigned long size);
 
 #endif /* __ASSEMBLY__ */
 #endif  /* _LINUX_IOPORT_H */
diff --git a/kernel/resource.c b/kernel/resource.c
index fc59dcc4795b..1d003a50ee17 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -827,3 +827,36 @@ static int __init reserve_setup(char *str)
 }
 
 __setup("reserve=", reserve_setup);
+
+/*
+ * Check if the requested addr and size spans more than any slot in the
+ * iomem resource tree.
+ */
+int iomem_map_sanity_check(resource_size_t addr, unsigned long size)
+{
+        struct resource *p = &iomem_resource;
+        int err = 0;
+        loff_t l;
+
+        read_lock(&resource_lock);
+        for (p = p->child; p ; p = r_next(NULL, p, &l)) {
+                /*
+                 * We can probably skip the resources without
+                 * IORESOURCE_IO attribute?
+                 */
+                if (p->start >= addr + size)
+                        continue;
+                if (p->end < addr)
+                        continue;
+                if (p->start <= addr && (p->end >= addr + size - 1))
+                        continue;
+                printk(KERN_WARNING "resource map sanity check conflict: "
+                       "0x%llx 0x%llx 0x%llx 0x%llx %s\n",
+                       addr, addr + size - 1, p->start, p->end, p->name);
+                err = -1;
+                break;
+        }
+        read_unlock(&resource_lock);
+
+        return err;
+}