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Subject[PATCH v3 1/5] sparc64: Define SPARC default fls function
Date
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>
---
arch/sparc/include/asm/bitops_64.h | 3 +-
arch/sparc/lib/Makefile | 1 +
arch/sparc/lib/fls.S | 67 ++++++++++++++++++++++++++++++++++++
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 2d52240..30aea56 100644
--- a/arch/sparc/include/asm/bitops_64.h
+++ b/arch/sparc/include/asm/bitops_64.h
@@ -22,9 +22,10 @@
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 a1a2d39..3b9f5e0 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 0000000..06b8d30
--- /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)
--
1.7.1
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