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[2001:470:27:1fa::2]) by smtp.gmail.com with ESMTPSA id y131sm1230397lfc.43.2019.01.24.18.58.26 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 24 Jan 2019 18:58:29 -0800 (PST) From: Max Filippov To: LKML Cc: Max Filippov , Andy Lutomirski , Arnd Bergmann , Geert Uytterhoeven , Paul Burton , Ralf Baechle , Thomas Gleixner Subject: [PATCH] treewide: get rid of HAVE_FUTEX_CMPXCHG Date: Thu, 24 Jan 2019 18:57:47 -0800 Message-Id: <20190125025747.1853-1-jcmvbkbc@gmail.com> X-Mailer: git-send-email 2.11.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org CONFIG_HAVE_FUTEX_CMPXCHG is currently used to determine if atomic_inatomic is always working or must be probed. For most architectures it is either selected, or it is known that they always have futex_atomic_cmpxchg_inatomic working. Drop HAVE_FUTEX_CMPXCHG from the Kconfig and let architectures that may not have it working define macro arch_have_futex_cmpxchg that probes whether futex_atomic_cmpxchg_inatomic is working, otherwise assume that it is working. Implement arch_have_futex_cmpxchg for MIPS, Xtensa and for the users of asm-generic/futex.h. Cc: Andy Lutomirski Cc: Arnd Bergmann Cc: Geert Uytterhoeven Cc: Paul Burton Cc: Ralf Baechle Cc: Thomas Gleixner Signed-off-by: Max Filippov --- arch/arc/Kconfig | 1 - arch/m68k/Kconfig | 1 - arch/mips/include/asm/futex.h | 2 ++ arch/riscv/Kconfig | 1 - arch/s390/Kconfig | 1 - arch/sh/Kconfig | 1 - arch/um/Kconfig | 1 - arch/xtensa/Kconfig | 1 - arch/xtensa/include/asm/futex.h | 4 ++++ include/asm-generic/futex.h | 2 ++ init/Kconfig | 8 -------- kernel/futex.c | 30 ++++++++---------------------- 12 files changed, 16 insertions(+), 37 deletions(-) diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig index 376366a7db81..01932be9f7e3 100644 --- a/arch/arc/Kconfig +++ b/arch/arc/Kconfig @@ -29,7 +29,6 @@ config ARC select HAVE_ARCH_KGDB select HAVE_ARCH_TRACEHOOK select HAVE_DEBUG_STACKOVERFLOW - select HAVE_FUTEX_CMPXCHG if FUTEX select HAVE_GENERIC_DMA_COHERENT select HAVE_IOREMAP_PROT select HAVE_KERNEL_GZIP diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig index e173ea2ff395..09499af5d22a 100644 --- a/arch/m68k/Kconfig +++ b/arch/m68k/Kconfig @@ -20,7 +20,6 @@ config M68K select GENERIC_STRNLEN_USER if MMU select ARCH_WANT_IPC_PARSE_VERSION select ARCH_USES_GETTIMEOFFSET if MMU && !COLDFIRE - select HAVE_FUTEX_CMPXCHG if MMU && FUTEX select HAVE_MOD_ARCH_SPECIFIC select MODULES_USE_ELF_REL select MODULES_USE_ELF_RELA diff --git a/arch/mips/include/asm/futex.h b/arch/mips/include/asm/futex.h index c14d798f3888..f61221d080fc 100644 --- a/arch/mips/include/asm/futex.h +++ b/arch/mips/include/asm/futex.h @@ -122,6 +122,8 @@ arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr) return ret; } +#define arch_have_futex_cmpxchg() (cpu_has_llsc) + static inline int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval, u32 newval) diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index feeeaa60697c..074966cdd41d 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -31,7 +31,6 @@ config RISCV select HAVE_ARCH_AUDITSYSCALL select HAVE_MEMBLOCK_NODE_MAP select HAVE_DMA_CONTIGUOUS - select HAVE_FUTEX_CMPXCHG if FUTEX select HAVE_GENERIC_DMA_COHERENT select HAVE_PERF_EVENTS select HAVE_SYSCALL_TRACEPOINTS diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index ed554b09eb3f..6f3819275d08 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -146,7 +146,6 @@ config S390 select HAVE_FTRACE_MCOUNT_RECORD select HAVE_FUNCTION_GRAPH_TRACER select HAVE_FUNCTION_TRACER - select HAVE_FUTEX_CMPXCHG if FUTEX select HAVE_GCC_PLUGINS select HAVE_KERNEL_BZIP2 select HAVE_KERNEL_GZIP diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig index a9c36f95744a..a04bc11c8819 100644 --- a/arch/sh/Kconfig +++ b/arch/sh/Kconfig @@ -50,7 +50,6 @@ config SUPERH select OLD_SIGACTION select PCI_DOMAINS if PCI select HAVE_ARCH_AUDITSYSCALL - select HAVE_FUTEX_CMPXCHG if FUTEX select HAVE_NMI select NEED_SG_DMA_LENGTH diff --git a/arch/um/Kconfig b/arch/um/Kconfig index ec9711d068b7..38c5ce3b64b1 100644 --- a/arch/um/Kconfig +++ b/arch/um/Kconfig @@ -10,7 +10,6 @@ config UML select HAVE_ARCH_AUDITSYSCALL select HAVE_ARCH_SECCOMP_FILTER select HAVE_UID16 - select HAVE_FUTEX_CMPXCHG if FUTEX select HAVE_DEBUG_KMEMLEAK select HAVE_DEBUG_BUGVERBOSE select GENERIC_IRQ_SHOW diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig index 7021d1e15909..a4d34de57809 100644 --- a/arch/xtensa/Kconfig +++ b/arch/xtensa/Kconfig @@ -25,7 +25,6 @@ config XTENSA select HAVE_DMA_CONTIGUOUS select HAVE_EXIT_THREAD select HAVE_FUNCTION_TRACER - select HAVE_FUTEX_CMPXCHG if !MMU select HAVE_HW_BREAKPOINT if PERF_EVENTS select HAVE_IRQ_TIME_ACCOUNTING select HAVE_OPROFILE diff --git a/arch/xtensa/include/asm/futex.h b/arch/xtensa/include/asm/futex.h index 505d09eff184..ac88d64f94e4 100644 --- a/arch/xtensa/include/asm/futex.h +++ b/arch/xtensa/include/asm/futex.h @@ -87,6 +87,10 @@ static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval, return ret; } +#if !XCHAL_HAVE_S32C1I +#define arch_have_futex_cmpxchg() (0) +#endif + static inline int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval, u32 newval) diff --git a/include/asm-generic/futex.h b/include/asm-generic/futex.h index fcb61b4659b3..deefe5b22b9b 100644 --- a/include/asm-generic/futex.h +++ b/include/asm-generic/futex.h @@ -136,6 +136,8 @@ arch_futex_atomic_op_inuser(int op, u32 oparg, int *oval, u32 __user *uaddr) return ret; } +#define arch_have_futex_cmpxchg() (0) + static inline int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval, u32 newval) diff --git a/init/Kconfig b/init/Kconfig index 513fa544a134..351f4c93f932 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1338,14 +1338,6 @@ config FUTEX_PI depends on FUTEX && RT_MUTEXES default y -config HAVE_FUTEX_CMPXCHG - bool - depends on FUTEX - help - Architectures should select this if futex_atomic_cmpxchg_inatomic() - is implemented and always working. This removes a couple of runtime - checks. - config EPOLL bool "Enable eventpoll support" if EXPERT default y diff --git a/kernel/futex.c b/kernel/futex.c index be3bff2315ff..5697c1f2254d 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -174,7 +174,11 @@ * double_lock_hb() and double_unlock_hb(), respectively. */ -#ifdef CONFIG_HAVE_FUTEX_CMPXCHG +/* + * Architectures should define this macro if futex_atomic_cmpxchg_inatomic() + * may not be always working. + */ +#ifdef arch_have_futex_cmpxchg #define futex_cmpxchg_enabled 1 #else static int __read_mostly futex_cmpxchg_enabled; @@ -3842,26 +3846,6 @@ COMPAT_SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val, } #endif /* CONFIG_COMPAT_32BIT_TIME */ -static void __init futex_detect_cmpxchg(void) -{ -#ifndef CONFIG_HAVE_FUTEX_CMPXCHG - u32 curval; - - /* - * This will fail and we want it. Some arch implementations do - * runtime detection of the futex_atomic_cmpxchg_inatomic() - * functionality. We want to know that before we call in any - * of the complex code paths. Also we want to prevent - * registration of robust lists in that case. NULL is - * guaranteed to fault and we get -EFAULT on functional - * implementation, the non-functional ones will return - * -ENOSYS. - */ - if (cmpxchg_futex_value_locked(&curval, NULL, 0, 0) == -EFAULT) - futex_cmpxchg_enabled = 1; -#endif -} - static int __init futex_init(void) { unsigned int futex_shift; @@ -3880,7 +3864,9 @@ static int __init futex_init(void) futex_hashsize, futex_hashsize); futex_hashsize = 1UL << futex_shift; - futex_detect_cmpxchg(); +#ifdef arch_have_futex_cmpxchg + futex_cmpxchg_enabled = arch_have_futex_cmpxchg(); +#endif for (i = 0; i < futex_hashsize; i++) { atomic_set(&futex_queues[i].waiters, 0); -- 2.11.0