[POWERPC] Add hand-coded assembly strcmp

We have an assembly version of strncmp for the bootwrapper, but not
for the kernel, so we end up using the C version in the kernel.  This
takes the strncmp code from the bootup and copies it to the kernel
proper, adding two instructions so it copes correctly with len==0.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

2 files changed, 15 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/ppc_ksyms.c b/arch/powerpc/kernel/ppc_ksyms.c
index a722ede726db..5a4c76eada48 100644
--- a/arch/powerpc/kernel/ppc_ksyms.c
+++ b/arch/powerpc/kernel/ppc_ksyms.c
@@ -78,6 +78,7 @@ EXPORT_SYMBOL(strncpy);
 EXPORT_SYMBOL(strcat);
 EXPORT_SYMBOL(strlen);
 EXPORT_SYMBOL(strcmp);
+EXPORT_SYMBOL(strncmp);
 
 EXPORT_SYMBOL(csum_partial);
 EXPORT_SYMBOL(csum_partial_copy_generic);
diff --git a/arch/powerpc/lib/string.S b/arch/powerpc/lib/string.S
index c4c622d8e6ac..49eb1f1a2bb4 100644
--- a/arch/powerpc/lib/string.S
+++ b/arch/powerpc/lib/string.S
@@ -75,6 +75,20 @@ _GLOBAL(strcmp)
         beq     1b
         blr
 
+_GLOBAL(strncmp)
+        PPC_LCMPI r5,0
+        beqlr
+        mtctr   r5
+        addi    r5,r3,-1
+        addi    r4,r4,-1
+1:      lbzu    r3,1(r5)
+        cmpwi   1,r3,0
+        lbzu    r0,1(r4)
+        subf.   r3,r0,r3
+        beqlr   1
+        bdnzt   eq,1b
+        blr
+
 _GLOBAL(strlen)
         addi    r4,r3,-1
 1:      lbzu    r0,1(r4)