sparc64: Define SPARC default fls function

fls will now require a boot time patching on T4 and above.
Redefining it under arch/sparc/lib.

Signed-off-by: Vijay Kumar <vijay.ac.kumar@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 70 insertions, 1 deletions

diff --git a/arch/sparc/include/asm/bitops_64.h b/arch/sparc/include/asm/bitops_64.h
index 2d522402a937..30aea561176f 100644
--- a/arch/sparc/include/asm/bitops_64.h
+++ b/arch/sparc/include/asm/bitops_64.h
@@ -22,9 +22,10 @@ void set_bit(unsigned long nr, volatile unsigned long *addr);
 void clear_bit(unsigned long nr, volatile unsigned long *addr);
 void change_bit(unsigned long nr, volatile unsigned long *addr);
 
+int fls(unsigned int word);
+
 #include <asm-generic/bitops/non-atomic.h>
 
-#include <asm-generic/bitops/fls.h>
 #include <asm-generic/bitops/__fls.h>
 #include <asm-generic/bitops/fls64.h>
 
diff --git a/arch/sparc/lib/Makefile b/arch/sparc/lib/Makefile
index a1a2d39ec96e..3b9f5e0c1bcd 100644
--- a/arch/sparc/lib/Makefile
+++ b/arch/sparc/lib/Makefile
@@ -16,6 +16,7 @@ lib-$(CONFIG_SPARC64) += atomic_64.o
 lib-$(CONFIG_SPARC32) += lshrdi3.o ashldi3.o
 lib-$(CONFIG_SPARC32) += muldi3.o bitext.o cmpdi2.o
 lib-$(CONFIG_SPARC64) += multi3.o
+lib-$(CONFIG_SPARC64) += fls.o
 
 lib-$(CONFIG_SPARC64) += copy_page.o clear_page.o bzero.o
 lib-$(CONFIG_SPARC64) += csum_copy.o csum_copy_from_user.o csum_copy_to_user.o
diff --git a/arch/sparc/lib/fls.S b/arch/sparc/lib/fls.S
new file mode 100644
index 000000000000..06b8d300bcae
--- /dev/null
+++ b/arch/sparc/lib/fls.S
@@ -0,0 +1,67 @@
+/* fls.S: SPARC default fls definition.
+ *
+ * SPARC default fls definition, which follows the same algorithm as
+ * in generic fls(). This function will be boot time patched on T4
+ * and onward.
+ */
+
+#include <linux/linkage.h>
+#include <asm/export.h>
+
+        .text
+        .register       %g2, #scratch
+        .register       %g3, #scratch
+ENTRY(fls)
+        brz,pn  %o0, 6f
+         mov    0, %o1
+        sethi   %hi(0xffff0000), %g3
+        mov     %o0, %g2
+        andcc   %o0, %g3, %g0
+        be,pt   %icc, 8f
+         mov    32, %o1
+        sethi   %hi(0xff000000), %g3
+        andcc   %g2, %g3, %g0
+        bne,pt  %icc, 3f
+         sethi  %hi(0xf0000000), %g3
+        sll     %o0, 8, %o0
+1:
+        add     %o1, -8, %o1
+        sra     %o0, 0, %o0
+        mov     %o0, %g2
+2:
+        sethi   %hi(0xf0000000), %g3
+3:
+        andcc   %g2, %g3, %g0
+        bne,pt  %icc, 4f
+         sethi  %hi(0xc0000000), %g3
+        sll     %o0, 4, %o0
+        add     %o1, -4, %o1
+        sra     %o0, 0, %o0
+        mov     %o0, %g2
+4:
+        andcc   %g2, %g3, %g0
+        be,a,pt %icc, 7f
+         sll    %o0, 2, %o0
+5:
+        xnor    %g0, %o0, %o0
+        srl     %o0, 31, %o0
+        sub     %o1, %o0, %o1
+6:
+        jmp     %o7 + 8
+         sra    %o1, 0, %o0
+7:
+        add     %o1, -2, %o1
+        ba,pt   %xcc, 5b
+         sra    %o0, 0, %o0
+8:
+        sll     %o0, 16, %o0
+        sethi   %hi(0xff000000), %g3
+        sra     %o0, 0, %o0
+        mov     %o0, %g2
+        andcc   %g2, %g3, %g0
+        bne,pt  %icc, 2b
+         mov    16, %o1
+        ba,pt   %xcc, 1b
+         sll    %o0, 8, %o0
+ENDPROC(fls)
+EXPORT_SYMBOL(fls)