parisc: Provide __ucmpdi2 to resolve undefined references in 32 bit builds.

The Debian experimental linux source package (3.8.5-1) build fails
with the following errors:
...
MODPOST 2016 modules
ERROR: "__ucmpdi2" [fs/btrfs/btrfs.ko] undefined!
ERROR: "__ucmpdi2" [drivers/md/dm-verity.ko] undefined!

The attached patch resolves this problem.  It is based on the s390
implementation of ucmpdi2.c.

Signed-off-by: John David Anglin <dave.anglin@bell.net>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Signed-off-by: Helge Deller <deller@gmx.de>

3 files changed, 29 insertions, 1 deletions

diff --git a/arch/parisc/kernel/parisc_ksyms.c b/arch/parisc/kernel/parisc_ksyms.c
index 6795dc6c995f..568b2c61ea02 100644
--- a/arch/parisc/kernel/parisc_ksyms.c
+++ b/arch/parisc/kernel/parisc_ksyms.c
@@ -120,11 +120,13 @@ extern void __ashrdi3(void);
 extern void __ashldi3(void);
 extern void __lshrdi3(void);
 extern void __muldi3(void);
+extern void __ucmpdi2(void);
 
 EXPORT_SYMBOL(__ashrdi3);
 EXPORT_SYMBOL(__ashldi3);
 EXPORT_SYMBOL(__lshrdi3);
 EXPORT_SYMBOL(__muldi3);
+EXPORT_SYMBOL(__ucmpdi2);
 
 asmlinkage void * __canonicalize_funcptr_for_compare(void *);
 EXPORT_SYMBOL(__canonicalize_funcptr_for_compare);
diff --git a/arch/parisc/lib/Makefile b/arch/parisc/lib/Makefile
index 5f2e6904d14a..5651536ac733 100644
--- a/arch/parisc/lib/Makefile
+++ b/arch/parisc/lib/Makefile
@@ -2,6 +2,7 @@
 # Makefile for parisc-specific library files
 #
 
-lib-y   := lusercopy.o bitops.o checksum.o io.o memset.o fixup.o memcpy.o
+lib-y   := lusercopy.o bitops.o checksum.o io.o memset.o fixup.o memcpy.o \
+           ucmpdi2.o
 
 obj-y   := iomap.o
diff --git a/arch/parisc/lib/ucmpdi2.c b/arch/parisc/lib/ucmpdi2.c
new file mode 100644
index 000000000000..149c016f32c5
--- /dev/null
+++ b/arch/parisc/lib/ucmpdi2.c
@@ -0,0 +1,25 @@
+#include <linux/module.h>
+
+union ull_union {
+        unsigned long long ull;
+        struct {
+                unsigned int high;
+                unsigned int low;
+        } ui;
+};
+
+int __ucmpdi2(unsigned long long a, unsigned long long b)
+{
+        union ull_union au = {.ull = a};
+        union ull_union bu = {.ull = b};
+
+        if (au.ui.high < bu.ui.high)
+                return 0;
+        else if (au.ui.high > bu.ui.high)
+                return 2;
+        if (au.ui.low < bu.ui.low)
+                return 0;
+        else if (au.ui.low > bu.ui.low)
+                return 2;
+        return 1;
+}