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Message-ID: <20140804115540.GA25890@gmail.com>
Date: Mon, 4 Aug 2014 13:55:40 +0200
From: Ingo Molnar <mingo@...nel.org>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: linux-kernel@...r.kernel.org, "H. Peter Anvin" <hpa@...or.com>,
Thomas Gleixner <tglx@...utronix.de>,
Andrew Morton <akpm@...ux-foundation.org>
Subject: [GIT PULL] x86/cleanups for v3.17
Linus,
Please pull the latest x86-cleanups-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-cleanups-for-linus
# HEAD: b08ee5f7e4135d64b8edd769367f8964a725122e x86: Simplify __HAVE_ARCH_CMPXCHG tests
Two cleanups.
Thanks,
Ingo
------------------>
Borislav Petkov (1):
x86: Simplify __HAVE_ARCH_CMPXCHG tests
Michal Nazarewicz (1):
x86/tsc: Get rid of custom DIV_ROUND() macro
arch/x86/include/asm/cmpxchg.h | 4 ++--
arch/x86/include/asm/cmpxchg_32.h | 2 --
arch/x86/include/asm/cmpxchg_64.h | 2 --
arch/x86/include/asm/mc146818rtc.h | 2 +-
arch/x86/include/asm/mutex_32.h | 16 ++--------------
arch/x86/kernel/acpi/boot.c | 4 ----
arch/x86/kernel/tsc.c | 7 +++----
7 files changed, 8 insertions(+), 29 deletions(-)
diff --git a/arch/x86/include/asm/cmpxchg.h b/arch/x86/include/asm/cmpxchg.h
index d47786a..99c105d7 100644
--- a/arch/x86/include/asm/cmpxchg.h
+++ b/arch/x86/include/asm/cmpxchg.h
@@ -4,6 +4,8 @@
#include <linux/compiler.h>
#include <asm/alternative.h> /* Provides LOCK_PREFIX */
+#define __HAVE_ARCH_CMPXCHG 1
+
/*
* Non-existant functions to indicate usage errors at link time
* (or compile-time if the compiler implements __compiletime_error().
@@ -143,7 +145,6 @@ extern void __add_wrong_size(void)
# include <asm/cmpxchg_64.h>
#endif
-#ifdef __HAVE_ARCH_CMPXCHG
#define cmpxchg(ptr, old, new) \
__cmpxchg(ptr, old, new, sizeof(*(ptr)))
@@ -152,7 +153,6 @@ extern void __add_wrong_size(void)
#define cmpxchg_local(ptr, old, new) \
__cmpxchg_local(ptr, old, new, sizeof(*(ptr)))
-#endif
/*
* xadd() adds "inc" to "*ptr" and atomically returns the previous
diff --git a/arch/x86/include/asm/cmpxchg_32.h b/arch/x86/include/asm/cmpxchg_32.h
index f8bf2ee..f7e1429 100644
--- a/arch/x86/include/asm/cmpxchg_32.h
+++ b/arch/x86/include/asm/cmpxchg_32.h
@@ -34,8 +34,6 @@ static inline void set_64bit(volatile u64 *ptr, u64 value)
: "memory");
}
-#define __HAVE_ARCH_CMPXCHG 1
-
#ifdef CONFIG_X86_CMPXCHG64
#define cmpxchg64(ptr, o, n) \
((__typeof__(*(ptr)))__cmpxchg64((ptr), (unsigned long long)(o), \
diff --git a/arch/x86/include/asm/cmpxchg_64.h b/arch/x86/include/asm/cmpxchg_64.h
index 614be87..1af9469 100644
--- a/arch/x86/include/asm/cmpxchg_64.h
+++ b/arch/x86/include/asm/cmpxchg_64.h
@@ -6,8 +6,6 @@ static inline void set_64bit(volatile u64 *ptr, u64 val)
*ptr = val;
}
-#define __HAVE_ARCH_CMPXCHG 1
-
#define cmpxchg64(ptr, o, n) \
({ \
BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
diff --git a/arch/x86/include/asm/mc146818rtc.h b/arch/x86/include/asm/mc146818rtc.h
index a55c7ef..0f555cc 100644
--- a/arch/x86/include/asm/mc146818rtc.h
+++ b/arch/x86/include/asm/mc146818rtc.h
@@ -13,7 +13,7 @@
#define RTC_ALWAYS_BCD 1 /* RTC operates in binary mode */
#endif
-#if defined(CONFIG_X86_32) && defined(__HAVE_ARCH_CMPXCHG)
+#if defined(CONFIG_X86_32)
/*
* This lock provides nmi access to the CMOS/RTC registers. It has some
* special properties. It is owned by a CPU and stores the index register
diff --git a/arch/x86/include/asm/mutex_32.h b/arch/x86/include/asm/mutex_32.h
index 0208c3c..85e6cda 100644
--- a/arch/x86/include/asm/mutex_32.h
+++ b/arch/x86/include/asm/mutex_32.h
@@ -100,23 +100,11 @@ do { \
static inline int __mutex_fastpath_trylock(atomic_t *count,
int (*fail_fn)(atomic_t *))
{
- /*
- * We have two variants here. The cmpxchg based one is the best one
- * because it never induce a false contention state. It is included
- * here because architectures using the inc/dec algorithms over the
- * xchg ones are much more likely to support cmpxchg natively.
- *
- * If not we fall back to the spinlock based variant - that is
- * just as efficient (and simpler) as a 'destructive' probing of
- * the mutex state would be.
- */
-#ifdef __HAVE_ARCH_CMPXCHG
+ /* cmpxchg because it never induces a false contention state. */
if (likely(atomic_cmpxchg(count, 1, 0) == 1))
return 1;
+
return 0;
-#else
- return fail_fn(count);
-#endif
}
#endif /* _ASM_X86_MUTEX_32_H */
diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 86281ff..a531f65 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -74,10 +74,6 @@ int acpi_fix_pin2_polarity __initdata;
static u64 acpi_lapic_addr __initdata = APIC_DEFAULT_PHYS_BASE;
#endif
-#ifndef __HAVE_ARCH_CMPXCHG
-#warning ACPI uses CMPXCHG, i486 and later hardware
-#endif
-
/* --------------------------------------------------------------------------
Boot-time Configuration
-------------------------------------------------------------------------- */
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 57e5ce1..8764232 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -234,9 +234,6 @@ static inline unsigned long long cycles_2_ns(unsigned long long cyc)
return ns;
}
-/* XXX surely we already have this someplace in the kernel?! */
-#define DIV_ROUND(n, d) (((n) + ((d) / 2)) / (d))
-
static void set_cyc2ns_scale(unsigned long cpu_khz, int cpu)
{
unsigned long long tsc_now, ns_now;
@@ -259,7 +256,9 @@ static void set_cyc2ns_scale(unsigned long cpu_khz, int cpu)
* time function is continuous; see the comment near struct
* cyc2ns_data.
*/
- data->cyc2ns_mul = DIV_ROUND(NSEC_PER_MSEC << CYC2NS_SCALE_FACTOR, cpu_khz);
+ data->cyc2ns_mul =
+ DIV_ROUND_CLOSEST(NSEC_PER_MSEC << CYC2NS_SCALE_FACTOR,
+ cpu_khz);
data->cyc2ns_shift = CYC2NS_SCALE_FACTOR;
data->cyc2ns_offset = ns_now -
mul_u64_u32_shr(tsc_now, data->cyc2ns_mul, CYC2NS_SCALE_FACTOR);
--
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