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authorLinus Torvalds <torvalds@linux-foundation.org>2014-01-23 18:34:03 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-01-23 18:34:03 -0800
commitf341535193c338b4ce4af8e32be51e6aae7f22a6 (patch)
treed054a10be84681b93ce53c348cde0d764e1e24a2 /arch/arm/include/asm/bitops.h
parent13c789a6b219aa23f917466c7e630566106b14c2 (diff)
parent857989a7fdd2f6de42272578b8aaa413ed6e63e4 (diff)
downloadlinux-f341535193c338b4ce4af8e32be51e6aae7f22a6.tar.bz2
Merge branch 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm
Pull ARM updates from Russell King: "In this set, we have: - Refactoring of some of the old StrongARM-1100 GPIO code to make things simpler by Dmitry Eremin-Solenikov - Read-only and non-executable support for modules on ARM from Laura Abbot - Removal of unnecessary set_drvdata() calls in AMBA code - Some non-executable support for kernel lowmem mappings at the 1MB section granularity, and dumping of kernel page tables via debugfs - Some improvements for the timer/clock code on Footbridge platforms, and cleanup some of the LED code there - Fix fls/ffs() signatures to match x86 to prevent build warnings, particularly where these are used with min/max() macros - Avoid using the bootmem allocator on ARM (patches from Santosh Shilimkar) - Various asid/unaligned access updates from Will Deacon" * 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm: (51 commits) ARM: SMP implementations are not supposed to return from smp_ops.cpu_die() ARM: ignore memory below PHYS_OFFSET Fix select-induced Kconfig warning for ZBOOT_ROM ARM: fix ffs/fls implementations to match x86 ARM: 7935/1: sa1100: collie: add gpio-keys configuration ARM: 7932/1: bcm: Add DEBUG_LL console support ARM: 7929/1: Remove duplicate SCHED_HRTICK config option ARM: 7928/1: kconfig: select HAVE_EFFICIENT_UNALIGNED_ACCESS for CPUv6+ && MMU ARM: 7927/1: dcache: select DCACHE_WORD_ACCESS for big-endian CPUs ARM: 7926/1: mm: flesh out and fix the comments in the ASID allocator ARM: 7925/1: mm: keep track of last ASID allocation to improve bitmap searching ARM: 7924/1: mm: don't bother with reserved ttbr0 when running with LPAE ARM: PCI: add legacy IDE IRQ implementation ARM: footbridge: cleanup LEDs code ARM: pgd allocation: retry on failure ARM: footbridge: add one-shot mode for DC21285 timer ARM: footbridge: add sched_clock implementation ARM: 7922/1: l2x0: add Marvell Tauros3 support ARM: 7877/1: use built-in byte swap function ARM: 7921/1: mcpm: remove redundant dsb instructions prior to sev ...
Diffstat (limited to 'arch/arm/include/asm/bitops.h')
-rw-r--r--arch/arm/include/asm/bitops.h54
1 files changed, 44 insertions, 10 deletions
diff --git a/arch/arm/include/asm/bitops.h b/arch/arm/include/asm/bitops.h
index e691ec91e4d3..b2e298a90d76 100644
--- a/arch/arm/include/asm/bitops.h
+++ b/arch/arm/include/asm/bitops.h
@@ -254,25 +254,59 @@ static inline int constant_fls(int x)
}
/*
- * On ARMv5 and above those functions can be implemented around
- * the clz instruction for much better code efficiency.
+ * On ARMv5 and above those functions can be implemented around the
+ * clz instruction for much better code efficiency. __clz returns
+ * the number of leading zeros, zero input will return 32, and
+ * 0x80000000 will return 0.
*/
+static inline unsigned int __clz(unsigned int x)
+{
+ unsigned int ret;
+
+ asm("clz\t%0, %1" : "=r" (ret) : "r" (x));
+ return ret;
+}
+
+/*
+ * fls() returns zero if the input is zero, otherwise returns the bit
+ * position of the last set bit, where the LSB is 1 and MSB is 32.
+ */
static inline int fls(int x)
{
- int ret;
-
if (__builtin_constant_p(x))
return constant_fls(x);
- asm("clz\t%0, %1" : "=r" (ret) : "r" (x));
- ret = 32 - ret;
- return ret;
+ return 32 - __clz(x);
+}
+
+/*
+ * __fls() returns the bit position of the last bit set, where the
+ * LSB is 0 and MSB is 31. Zero input is undefined.
+ */
+static inline unsigned long __fls(unsigned long x)
+{
+ return fls(x) - 1;
+}
+
+/*
+ * ffs() returns zero if the input was zero, otherwise returns the bit
+ * position of the first set bit, where the LSB is 1 and MSB is 32.
+ */
+static inline int ffs(int x)
+{
+ return fls(x & -x);
+}
+
+/*
+ * __ffs() returns the bit position of the first bit set, where the
+ * LSB is 0 and MSB is 31. Zero input is undefined.
+ */
+static inline unsigned long __ffs(unsigned long x)
+{
+ return ffs(x) - 1;
}
-#define __fls(x) (fls(x) - 1)
-#define ffs(x) ({ unsigned long __t = (x); fls(__t & -__t); })
-#define __ffs(x) (ffs(x) - 1)
#define ffz(x) __ffs( ~(x) )
#endif