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Message-Id: <1304498932-30127-2-git-send-email-ying.huang@intel.com>
Date: Wed, 4 May 2011 16:48:49 +0800
From: Huang Ying <ying.huang@...el.com>
To: Len Brown <lenb@...nel.org>
Cc: linux-kernel@...r.kernel.org, Andi Kleen <andi@...stfloor.org>,
Tony Luck <tony.luck@...el.com>, ying.huang@...el.com,
linux-acpi@...r.kernel.org, Richard Henderson <rth@...ddle.net>,
Mikael Starvik <starvik@...s.com>,
David Howells <dhowells@...hat.com>,
Yoshinori Sato <ysato@...rs.sourceforge.jp>,
Hirokazu Takata <takata@...ux-m32r.org>,
Geert Uytterhoeven <geert@...ux-m68k.org>,
Michal Simek <monstr@...str.eu>,
Ralf Baechle <ralf@...ux-mips.org>,
Kyle McMartin <kyle@...artin.ca>,
Martin Schwidefsky <schwidefsky@...ibm.com>,
Chen Liqin <liqin.chen@...plusct.com>,
"David S. Miller" <davem@...emloft.net>,
Ingo Molnar <mingo@...hat.com>, Chris Zankel <chris@...kel.net>
Subject: [PATCH -v5 1/4] Add Kconfig option ARCH_HAVE_NMI_SAFE_CMPXCHG
cmpxchg() is widely used by lockless code, including NMI-safe lockless
code. But on some architectures, the cmpxchg() implementation is not
NMI-safe, on these architectures the lockless code may need to a
spin_trylock_irqsave() based implementation.
This patch adds a Kconfig option: ARCH_HAVE_NMI_SAFE_CMPXCHG, so that
NMI-safe lockless code can depend on it or provide different
implementation according to it.
On many architectures, cmpxchg is only NMI-safe for several specific
operand sizes. So, ARCH_HAVE_NMI_SAFE_CMPXCHG define in this patch
only guarantees cmpxchg is NMI-safe for sizeof(unsigned long).
Signed-off-by: Huang Ying <ying.huang@...el.com>
Acked-by: Mike Frysinger <vapier@...too.org>
Acked-by: Paul Mundt <lethal@...ux-sh.org>
Acked-by: Hans-Christian Egtvedt <hans-christian.egtvedt@...el.com>
Acked-by: Benjamin Herrenschmidt <benh@...nel.crashing.org>
Acked-by: Chris Metcalf <cmetcalf@...era.com>
CC: Richard Henderson <rth@...ddle.net>
CC: Mikael Starvik <starvik@...s.com>
CC: David Howells <dhowells@...hat.com>
CC: Yoshinori Sato <ysato@...rs.sourceforge.jp>
CC: Tony Luck <tony.luck@...el.com>
CC: Hirokazu Takata <takata@...ux-m32r.org>
CC: Geert Uytterhoeven <geert@...ux-m68k.org>
CC: Michal Simek <monstr@...str.eu>
CC: Ralf Baechle <ralf@...ux-mips.org>
CC: Kyle McMartin <kyle@...artin.ca>
CC: Martin Schwidefsky <schwidefsky@...ibm.com>
CC: Chen Liqin <liqin.chen@...plusct.com>
CC: "David S. Miller" <davem@...emloft.net>
CC: Ingo Molnar <mingo@...hat.com>
CC: Chris Zankel <chris@...kel.net>
---
arch/Kconfig | 3 +++
arch/alpha/Kconfig | 1 +
arch/avr32/Kconfig | 1 +
arch/frv/Kconfig | 1 +
arch/ia64/Kconfig | 1 +
arch/m68k/Kconfig | 1 +
arch/parisc/Kconfig | 1 +
arch/powerpc/Kconfig | 1 +
arch/s390/Kconfig | 1 +
arch/sh/Kconfig | 1 +
arch/sparc/Kconfig | 1 +
arch/tile/Kconfig | 1 +
arch/x86/Kconfig | 1 +
13 files changed, 15 insertions(+)
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -178,4 +178,7 @@ config HAVE_ARCH_JUMP_LABEL
config HAVE_ARCH_MUTEX_CPU_RELAX
bool
+config ARCH_HAVE_NMI_SAFE_CMPXCHG
+ bool
+
source "kernel/gcov/Kconfig"
--- a/arch/alpha/Kconfig
+++ b/arch/alpha/Kconfig
@@ -12,6 +12,7 @@ config ALPHA
select GENERIC_IRQ_PROBE
select AUTO_IRQ_AFFINITY if SMP
select GENERIC_IRQ_SHOW
+ select ARCH_HAVE_NMI_SAFE_CMPXCHG
help
The Alpha is a 64-bit general-purpose processor designed and
marketed by the Digital Equipment Corporation of blessed memory,
--- a/arch/avr32/Kconfig
+++ b/arch/avr32/Kconfig
@@ -10,6 +10,7 @@ config AVR32
select GENERIC_IRQ_PROBE
select HARDIRQS_SW_RESEND
select GENERIC_IRQ_SHOW
+ select ARCH_HAVE_NMI_SAFE_CMPXCHG
help
AVR32 is a high-performance 32-bit RISC microprocessor core,
designed for cost-sensitive embedded applications, with particular
--- a/arch/frv/Kconfig
+++ b/arch/frv/Kconfig
@@ -7,6 +7,7 @@ config FRV
select HAVE_PERF_EVENTS
select HAVE_GENERIC_HARDIRQS
select GENERIC_IRQ_SHOW
+ select ARCH_HAVE_NMI_SAFE_CMPXCHG
config ZONE_DMA
bool
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -27,6 +27,7 @@ config IA64
select GENERIC_PENDING_IRQ if SMP
select IRQ_PER_CPU
select GENERIC_IRQ_SHOW
+ select ARCH_HAVE_NMI_SAFE_CMPXCHG
default y
help
The Itanium Processor Family is Intel's 64-bit successor to
--- a/arch/m68k/Kconfig
+++ b/arch/m68k/Kconfig
@@ -5,6 +5,7 @@ config M68K
select HAVE_AOUT if MMU
select GENERIC_ATOMIC64 if MMU
select HAVE_GENERIC_HARDIRQS if !MMU
+ select ARCH_HAVE_NMI_SAFE_CMPXCHG if RMW_INSNS
config RWSEM_GENERIC_SPINLOCK
bool
--- a/arch/parisc/Kconfig
+++ b/arch/parisc/Kconfig
@@ -15,6 +15,7 @@ config PARISC
select HAVE_GENERIC_HARDIRQS
select GENERIC_IRQ_PROBE
select IRQ_PER_CPU
+ select ARCH_HAVE_NMI_SAFE_CMPXCHG
help
The PA-RISC microprocessor is designed by Hewlett-Packard and used
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -140,6 +140,7 @@ config PPC
select IRQ_PER_CPU
select GENERIC_IRQ_SHOW
select GENERIC_IRQ_SHOW_LEVEL
+ select ARCH_HAVE_NMI_SAFE_CMPXCHG
config EARLY_PRINTK
bool
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -81,6 +81,7 @@ config S390
select INIT_ALL_POSSIBLE
select HAVE_IRQ_WORK
select HAVE_PERF_EVENTS
+ select ARCH_HAVE_NMI_SAFE_CMPXCHG
select HAVE_KERNEL_GZIP
select HAVE_KERNEL_BZIP2
select HAVE_KERNEL_LZMA
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig
@@ -11,6 +11,7 @@ config SUPERH
select HAVE_DMA_ATTRS
select HAVE_IRQ_WORK
select HAVE_PERF_EVENTS
+ select ARCH_HAVE_NMI_SAFE_CMPXCHG if (GUSA_RB || CPU_SH4A)
select PERF_USE_VMALLOC
select HAVE_KERNEL_GZIP
select HAVE_KERNEL_BZIP2
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -53,6 +53,7 @@ config SPARC64
select HAVE_GENERIC_HARDIRQS
select GENERIC_IRQ_SHOW
select IRQ_PREFLOW_FASTEOI
+ select ARCH_HAVE_NMI_SAFE_CMPXCHG
config ARCH_DEFCONFIG
string
--- a/arch/tile/Kconfig
+++ b/arch/tile/Kconfig
@@ -12,6 +12,7 @@ config TILE
select GENERIC_IRQ_PROBE
select GENERIC_PENDING_IRQ if SMP
select GENERIC_IRQ_SHOW
+ select ARCH_HAVE_NMI_SAFE_CMPXCHG if !M386
# FIXME: investigate whether we need/want these options.
# select HAVE_IOREMAP_PROT
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -72,6 +72,7 @@ config X86
select IRQ_FORCED_THREADING
select USE_GENERIC_SMP_HELPERS if SMP
select ARCH_NO_SYSDEV_OPS
+ select ARCH_HAVE_NMI_SAFE_CMPXCHG
config INSTRUCTION_DECODER
def_bool (KPROBES || PERF_EVENTS)
--
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