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-rw-r--r--lib/Makefile2
-rw-r--r--lib/check_signature.c26
2 files changed, 27 insertions, 1 deletions
diff --git a/lib/Makefile b/lib/Makefile
index d1b366b..d7a93ff 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -13,7 +13,7 @@ lib-$(CONFIG_SMP) += cpumask.o
lib-y += kobject.o kref.o kobject_uevent.o klist.o
obj-y += div64.o sort.o parser.o halfmd4.o debug_locks.o random32.o \
- bust_spinlocks.o hexdump.o
+ bust_spinlocks.o hexdump.o check_signature.o
ifeq ($(CONFIG_DEBUG_KOBJECT),y)
CFLAGS_kobject.o += -DDEBUG
diff --git a/lib/check_signature.c b/lib/check_signature.c
new file mode 100644
index 0000000..fd6af19
--- /dev/null
+++ b/lib/check_signature.c
@@ -0,0 +1,26 @@
+#include <linux/io.h>
+#include <linux/module.h>
+
+/**
+ * check_signature - find BIOS signatures
+ * @io_addr: mmio address to check
+ * @signature: signature block
+ * @length: length of signature
+ *
+ * Perform a signature comparison with the mmio address io_addr. This
+ * address should have been obtained by ioremap.
+ * Returns 1 on a match.
+ */
+
+int check_signature(const volatile void __iomem *io_addr,
+ const unsigned char *signature, int length)
+{
+ while (length--) {
+ if (readb(io_addr) != *signature)
+ return 0;
+ io_addr++;
+ signature++;
+ }
+ return 1;
+}
+EXPORT_SYMBOL(check_signature);