s390/bitops: use generic find bit functions / reimplement _left variant

Just like all other architectures we should use out-of-line find bit
operations, since the inline variant bloat the size of the kernel image.
And also like all other architecures we should only supply optimized
variants of the __ffs, ffs, etc. primitives.

Therefore this patch removes the inlined s390 find bit functions and uses
the generic out-of-line variants instead.

The optimization of the primitives follows with the next patch.

With this patch also the functions find_first_bit_left() and
find_next_bit_left() have been reimplemented, since logically, they are
nothing else but a find_first_bit()/find_next_bit() implementation that
use an inverted __fls() instead of __ffs().
Also the restriction that these functions only work on machines which
support the "flogr" instruction is gone now.

This reduces the size of the kernel image (defconfig, -march=z9-109)
by 144,482 bytes.
Alone the size of the function build_sched_domains() gets reduced from
7 KB to 3,5 KB.

We also git rid of unused functions like find_first_bit_le()...

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/Kconfig

@@ -99,6 +99,7 @@ config S390
 	select CLONE_BACKWARDS2
 	select GENERIC_CLOCKEVENTS
 	select GENERIC_CPU_DEVICES if !SMP
+	select GENERIC_FIND_FIRST_BIT
 	select GENERIC_SMP_IDLE_THREAD
 	select GENERIC_TIME_VSYSCALL_OLD
 	select HAVE_ALIGNED_STRUCT_PAGE if SLUB

arch/s390/kernel/Makefile

@@ -28,7 +28,7 @@ CFLAGS_ptrace.o		+= -DUTS_MACHINE='"$(UTS_MACHINE)"'
 
 CFLAGS_sysinfo.o += -Iinclude/math-emu -Iarch/s390/math-emu -w
 
-obj-y	:= bitmap.o traps.o time.o process.o base.o early.o setup.o vtime.o
+obj-y	:= traps.o time.o process.o base.o early.o setup.o vtime.o
 obj-y	+= processor.o sys_s390.o ptrace.o signal.o cpcmd.o ebcdic.o nmi.o
 obj-y	+= debug.o irq.o ipl.o dis.o diag.o sclp.o vdso.o
 obj-y	+= sysinfo.o jump_label.o lgr.o os_info.o machine_kexec.o pgm_check.o

arch/s390/kernel/bitmap.c

@@ -1,48 +0,0 @@
-/*
- *    Bitmaps for set_bit, clear_bit, test_and_set_bit, ...
- *    See include/asm/{bitops.h|posix_types.h} for details
- *
- *    Copyright IBM Corp. 1999, 2009
- *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>,
- */
-
-#include <linux/bitops.h>
-#include <linux/module.h>
-
-const char _zb_findmap[] = {
-	0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,
-	0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,5,
-	0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,
-	0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,6,
-	0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,
-	0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,5,
-	0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,
-	0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,7,
-	0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,
-	0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,5,
-	0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,
-	0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,6,
-	0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,
-	0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,5,
-	0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,
-	0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,8 };
-EXPORT_SYMBOL(_zb_findmap);
-
-const char _sb_findmap[] = {
-	8,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
-	4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
-	5,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
-	4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
-	6,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
-	4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
-	5,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
-	4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
-	7,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
-	4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
-	5,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
-	4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
-	6,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
-	4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
-	5,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
-	4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0 };
-EXPORT_SYMBOL(_sb_findmap);

arch/s390/lib/Makefile

@@ -2,7 +2,7 @@
 # Makefile for s390-specific library files..
 #
 
-lib-y += delay.o string.o uaccess_std.o uaccess_pt.o
+lib-y += delay.o string.o uaccess_std.o uaccess_pt.o find.o
 obj-$(CONFIG_32BIT) += div64.o qrnnd.o ucmpdi2.o mem32.o
 obj-$(CONFIG_64BIT) += mem64.o
 lib-$(CONFIG_64BIT) += uaccess_mvcos.o

arch/s390/lib/find.c

@@ -0,0 +1,77 @@
+/*
+ * MSB0 numbered special bitops handling.
+ *
+ * On s390x the bits are numbered:
+ *   |0..............63|64............127|128...........191|192...........255|
+ * and on s390:
+ *   |0.....31|31....63|64....95|96...127|128..159|160..191|192..223|224..255|
+ *
+ * The reason for this bit numbering is the fact that the hardware sets bits
+ * in a bitmap starting at bit 0 (MSB) and we don't want to scan the bitmap
+ * from the 'wrong end'.
+ */
+
+#include <linux/compiler.h>
+#include <linux/bitops.h>
+#include <linux/export.h>
+
+unsigned long find_first_bit_left(const unsigned long *addr, unsigned long size)
+{
+	const unsigned long *p = addr;
+	unsigned long result = 0;
+	unsigned long tmp;
+
+	while (size & ~(BITS_PER_LONG - 1)) {
+		if ((tmp = *(p++)))
+			goto found;
+		result += BITS_PER_LONG;
+		size -= BITS_PER_LONG;
+	}
+	if (!size)
+		return result;
+	tmp = (*p) & (~0UL << (BITS_PER_LONG - size));
+	if (!tmp)		/* Are any bits set? */
+		return result + size;	/* Nope. */
+found:
+	return result + (__fls(tmp) ^ (BITS_PER_LONG - 1));
+}
+EXPORT_SYMBOL(find_first_bit_left);
+
+unsigned long find_next_bit_left(const unsigned long *addr, unsigned long size,
+				 unsigned long offset)
+{
+	const unsigned long *p = addr + (offset / BITS_PER_LONG);
+	unsigned long result = offset & ~(BITS_PER_LONG - 1);
+	unsigned long tmp;
+
+	if (offset >= size)
+		return size;
+	size -= result;
+	offset %= BITS_PER_LONG;
+	if (offset) {
+		tmp = *(p++);
+		tmp &= (~0UL >> offset);
+		if (size < BITS_PER_LONG)
+			goto found_first;
+		if (tmp)
+			goto found_middle;
+		size -= BITS_PER_LONG;
+		result += BITS_PER_LONG;
+	}
+	while (size & ~(BITS_PER_LONG-1)) {
+		if ((tmp = *(p++)))
+			goto found_middle;
+		result += BITS_PER_LONG;
+		size -= BITS_PER_LONG;
+	}
+	if (!size)
+		return result;
+	tmp = *p;
+found_first:
+	tmp &= (~0UL << (BITS_PER_LONG - size));
+	if (!tmp)		/* Are any bits set? */
+		return result + size;	/* Nope. */
+found_middle:
+	return result + (__fls(tmp) ^ (BITS_PER_LONG - 1));
+}
+EXPORT_SYMBOL(find_next_bit_left);