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@xxxxxxxxx> Acked-by: Mike Frysinger <vapier@xxxxxxxxxx> Acked-by: Paul Mundt <lethal@xxxxxxxxxxxx> Acked-by: Hans-Christian Egtvedt <hans-christian.egtvedt@xxxxxxxxx> Acked-by: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> Acked-by: Chris Metcalf <cmetcalf@xxxxxxxxxx> CC: Richard Henderson <rth@xxxxxxxxxxx> CC: Mikael Starvik <starvik@xxxxxxxx> CC: David Howells <dhowells@xxxxxxxxxx> CC: Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx> CC: Tony Luck <tony.luck@xxxxxxxxx> CC: Hirokazu Takata <takata@xxxxxxxxxxxxxx> CC: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> CC: Michal Simek <monstr@xxxxxxxxx> CC: Ralf Baechle <ralf@xxxxxxxxxxxxxx> CC: Kyle McMartin <kyle@xxxxxxxxxxx> CC: Martin Schwidefsky <schwidefsky@xxxxxxxxxx> CC: Chen Liqin <liqin.chen@xxxxxxxxxxxxx> CC: "David S. Miller" <davem@xxxxxxxxxxxxx> CC: Ingo Molnar <mingo@xxxxxxxxxx> CC: Chris Zankel <chris@xxxxxxxxxx> --- 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) -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
