IO resources, x86: ioremap sanity check to catch mapping requests exceeding the BAR...

Go through the iomem resource tree to check if any of the ioremap()
requests span more than any slot in the iomem resource tree and do
a WARN_ON() if we hit this check.

This will raise a red-flag, if some driver is mapping more than what
is needed. And hopefully identify possible corruptions much earlier.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index d4b6e6a29ae3597c45071805f734a502a12d6ab2..c818b45bd07d3bade0b48174b0436d39f4134fd2 100644 (file)
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -149,6 +149,12 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
        if (is_ISA_range(phys_addr, last_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..
         */

diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index fded376b94e3fdb53aa532408b63c4059502e24d..01712cf1a38b3b47d5f40f7b7ba145f343f286c5 100644 (file)
--- 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 fc59dcc4795b772c9aae54f266d50d9a79703db2..1d003a50ee17a1bd6291ba3cd9472ecbeb95ae27 100644 (file)
--- 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;
+}