diff options
author | Arnd Bergmann <arnd@arndb.de> | 2021-10-26 12:03:48 +0200 |
---|---|---|
committer | Thomas Gleixner <tglx@linutronix.de> | 2021-11-25 00:02:28 +0100 |
commit | 3297481d688a5cc2973ea58bd78e66b8639748b1 (patch) | |
tree | 3f9e7d8fb1601489125df8c689a28d3e29c8ef63 | |
parent | 3f2bedabb62c6210df63b604dc988d2f7f56f947 (diff) |
futex: Remove futex_cmpxchg detection
Now that all architectures have a working futex implementation in any
configuration, remove the runtime detection code.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Acked-by: Vineet Gupta <vgupta@kernel.org>
Acked-by: Max Filippov <jcmvbkbc@gmail.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Link: https://lore.kernel.org/r/20211026100432.1730393-2-arnd@kernel.org
-rw-r--r-- | arch/arc/Kconfig | 1 | ||||
-rw-r--r-- | arch/arm/Kconfig | 1 | ||||
-rw-r--r-- | arch/arm64/Kconfig | 1 | ||||
-rw-r--r-- | arch/csky/Kconfig | 1 | ||||
-rw-r--r-- | arch/m68k/Kconfig | 1 | ||||
-rw-r--r-- | arch/riscv/Kconfig | 1 | ||||
-rw-r--r-- | arch/s390/Kconfig | 1 | ||||
-rw-r--r-- | arch/sh/Kconfig | 1 | ||||
-rw-r--r-- | arch/um/Kconfig | 1 | ||||
-rw-r--r-- | arch/um/kernel/skas/uaccess.c | 1 | ||||
-rw-r--r-- | arch/xtensa/Kconfig | 1 | ||||
-rw-r--r-- | init/Kconfig | 8 | ||||
-rw-r--r-- | kernel/futex/core.c | 35 | ||||
-rw-r--r-- | kernel/futex/futex.h | 6 | ||||
-rw-r--r-- | kernel/futex/syscalls.c | 22 |
15 files changed, 0 insertions, 82 deletions
diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig index b4ae6058902a..f74d9860a442 100644 --- a/arch/arc/Kconfig +++ b/arch/arc/Kconfig @@ -32,7 +32,6 @@ config ARC select HAVE_ARCH_TRANSPARENT_HUGEPAGE if ARC_MMU_V4 select HAVE_DEBUG_STACKOVERFLOW select HAVE_DEBUG_KMEMLEAK - select HAVE_FUTEX_CMPXCHG if FUTEX select HAVE_IOREMAP_PROT select HAVE_KERNEL_GZIP select HAVE_KERNEL_LZMA diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index f0f9e8bec83a..2948487346dc 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -92,7 +92,6 @@ config ARM select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL select HAVE_FUNCTION_GRAPH_TRACER if !THUMB2_KERNEL && !CC_IS_CLANG select HAVE_FUNCTION_TRACER if !XIP_KERNEL && !(THUMB2_KERNEL && CC_IS_CLANG) - select HAVE_FUTEX_CMPXCHG if FUTEX select HAVE_GCC_PLUGINS select HAVE_HW_BREAKPOINT if PERF_EVENTS && (CPU_V6 || CPU_V6K || CPU_V7) select HAVE_IRQ_TIME_ACCOUNTING diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index c4207cf9bb17..5e2dfef78956 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -194,7 +194,6 @@ config ARM64 select HAVE_REGS_AND_STACK_ACCESS_API select HAVE_POSIX_CPU_TIMERS_TASK_WORK select HAVE_FUNCTION_ARG_ACCESS_API - select HAVE_FUTEX_CMPXCHG if FUTEX select MMU_GATHER_RCU_TABLE_FREE select HAVE_RSEQ select HAVE_STACKPROTECTOR diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig index aed2b3e734ee..132f43f12dd8 100644 --- a/arch/csky/Kconfig +++ b/arch/csky/Kconfig @@ -52,7 +52,6 @@ config CSKY select HAVE_FUNCTION_TRACER select HAVE_FUNCTION_GRAPH_TRACER select HAVE_FUNCTION_ERROR_INJECTION - select HAVE_FUTEX_CMPXCHG if FUTEX && SMP select HAVE_FTRACE_MCOUNT_RECORD select HAVE_KERNEL_GZIP select HAVE_KERNEL_LZO diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig index 0b50da08a9c5..15a793c5b2dc 100644 --- a/arch/m68k/Kconfig +++ b/arch/m68k/Kconfig @@ -20,7 +20,6 @@ config M68K select HAVE_ASM_MODVERSIONS select HAVE_DEBUG_BUGVERBOSE select HAVE_EFFICIENT_UNALIGNED_ACCESS if !CPU_HAS_NO_UNALIGNED - select HAVE_FUTEX_CMPXCHG if MMU && FUTEX select HAVE_MOD_ARCH_SPECIFIC select HAVE_UID16 select MMU_GATHER_NO_RANGE if MMU diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 821252b65f89..09abf62ae0ad 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -83,7 +83,6 @@ config RISCV select HAVE_DMA_CONTIGUOUS if MMU select HAVE_EBPF_JIT if MMU select HAVE_FUNCTION_ERROR_INJECTION - select HAVE_FUTEX_CMPXCHG if FUTEX select HAVE_GCC_PLUGINS select HAVE_GENERIC_VDSO if MMU && 64BIT select HAVE_IRQ_TIME_ACCOUNTING diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index 8857ec3b97eb..f614562d74f0 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -165,7 +165,6 @@ config S390 select HAVE_FUNCTION_ERROR_INJECTION select HAVE_FUNCTION_GRAPH_TRACER select HAVE_FUNCTION_TRACER - select HAVE_FUTEX_CMPXCHG if FUTEX select HAVE_GCC_PLUGINS select HAVE_GENERIC_VDSO select HAVE_IOREMAP_PROT if PCI diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig index 70afb30e0b32..2474a04ceac4 100644 --- a/arch/sh/Kconfig +++ b/arch/sh/Kconfig @@ -34,7 +34,6 @@ config SUPERH select HAVE_FAST_GUP if MMU select HAVE_FUNCTION_GRAPH_TRACER select HAVE_FUNCTION_TRACER - select HAVE_FUTEX_CMPXCHG if FUTEX select HAVE_FTRACE_MCOUNT_RECORD select HAVE_HW_BREAKPOINT select HAVE_IOREMAP_PROT if MMU && !X2TLB diff --git a/arch/um/Kconfig b/arch/um/Kconfig index c18b45f75d41..c906250d4970 100644 --- a/arch/um/Kconfig +++ b/arch/um/Kconfig @@ -14,7 +14,6 @@ config UML select HAVE_ARCH_SECCOMP_FILTER select HAVE_ASM_MODVERSIONS select HAVE_UID16 - select HAVE_FUTEX_CMPXCHG if FUTEX select HAVE_DEBUG_KMEMLEAK select HAVE_DEBUG_BUGVERBOSE select NO_DMA if !UML_DMA_EMULATION diff --git a/arch/um/kernel/skas/uaccess.c b/arch/um/kernel/skas/uaccess.c index a509be911026..9e37a7c05990 100644 --- a/arch/um/kernel/skas/uaccess.c +++ b/arch/um/kernel/skas/uaccess.c @@ -348,7 +348,6 @@ EXPORT_SYMBOL(arch_futex_atomic_op_inuser); * 0 - On success * -EFAULT - User access resulted in a page fault * -EAGAIN - Atomic operation was unable to complete due to contention - * -ENOSYS - Function not implemented (only if !HAVE_FUTEX_CMPXCHG) */ int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig index 0e56bad058fa..8ac599aa6d99 100644 --- a/arch/xtensa/Kconfig +++ b/arch/xtensa/Kconfig @@ -31,7 +31,6 @@ config XTENSA select HAVE_DMA_CONTIGUOUS select HAVE_EXIT_THREAD select HAVE_FUNCTION_TRACER - select HAVE_FUTEX_CMPXCHG if !MMU && FUTEX select HAVE_HW_BREAKPOINT if PERF_EVENTS select HAVE_IRQ_TIME_ACCOUNTING select HAVE_PCI diff --git a/init/Kconfig b/init/Kconfig index 3f5aa5063f55..76d89db5657b 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1592,14 +1592,6 @@ 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/core.c b/kernel/futex/core.c index 25d8a88b32e5..926c2bb752bc 100644 --- a/kernel/futex/core.c +++ b/kernel/futex/core.c @@ -41,11 +41,6 @@ #include "futex.h" #include "../locking/rtmutex_common.h" -#ifndef CONFIG_HAVE_FUTEX_CMPXCHG -int __read_mostly futex_cmpxchg_enabled; -#endif - - /* * The base of the bucket array and its size are always used together * (after initialization only in futex_hash()), so ensure that they @@ -776,9 +771,6 @@ static void exit_robust_list(struct task_struct *curr) unsigned long futex_offset; int rc; - if (!futex_cmpxchg_enabled) - return; - /* * Fetch the list head (which was registered earlier, via * sys_set_robust_list()): @@ -874,9 +866,6 @@ static void compat_exit_robust_list(struct task_struct *curr) compat_long_t futex_offset; int rc; - if (!futex_cmpxchg_enabled) - return; - /* * Fetch the list head (which was registered earlier, via * sys_set_robust_list()): @@ -950,8 +939,6 @@ static void exit_pi_state_list(struct task_struct *curr) struct futex_hash_bucket *hb; union futex_key key = FUTEX_KEY_INIT; - if (!futex_cmpxchg_enabled) - return; /* * We are a ZOMBIE and nobody can enqueue itself on * pi_state_list anymore, but we have to be careful @@ -1125,26 +1112,6 @@ void futex_exit_release(struct task_struct *tsk) futex_cleanup_end(tsk, FUTEX_STATE_DEAD); } -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 (futex_cmpxchg_value_locked(&curval, NULL, 0, 0) == -EFAULT) - futex_cmpxchg_enabled = 1; -#endif -} - static int __init futex_init(void) { unsigned int futex_shift; @@ -1163,8 +1130,6 @@ static int __init futex_init(void) futex_hashsize, futex_hashsize); futex_hashsize = 1UL << futex_shift; - futex_detect_cmpxchg(); - for (i = 0; i < futex_hashsize; i++) { atomic_set(&futex_queues[i].waiters, 0); plist_head_init(&futex_queues[i].chain); diff --git a/kernel/futex/futex.h b/kernel/futex/futex.h index 040ae4277cb0..c264cbeab71c 100644 --- a/kernel/futex/futex.h +++ b/kernel/futex/futex.h @@ -27,12 +27,6 @@ #define FLAGS_CLOCKRT 0x02 #define FLAGS_HAS_TIMEOUT 0x04 -#ifdef CONFIG_HAVE_FUTEX_CMPXCHG -#define futex_cmpxchg_enabled 1 -#else -extern int __read_mostly futex_cmpxchg_enabled; -#endif - #ifdef CONFIG_FAIL_FUTEX extern bool should_fail_futex(bool fshared); #else diff --git a/kernel/futex/syscalls.c b/kernel/futex/syscalls.c index 6f91a07a6a83..086a22d1adb7 100644 --- a/kernel/futex/syscalls.c +++ b/kernel/futex/syscalls.c @@ -29,8 +29,6 @@ SYSCALL_DEFINE2(set_robust_list, struct robust_list_head __user *, head, size_t, len) { - if (!futex_cmpxchg_enabled) - return -ENOSYS; /* * The kernel knows only one size for now: */ @@ -56,9 +54,6 @@ SYSCALL_DEFINE3(get_robust_list, int, pid, unsigned long ret; struct task_struct *p; - if (!futex_cmpxchg_enabled) - return -ENOSYS; - rcu_read_lock(); ret = -ESRCH; @@ -104,17 +99,6 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout, } switch (cmd) { - case FUTEX_LOCK_PI: - case FUTEX_LOCK_PI2: - case FUTEX_UNLOCK_PI: - case FUTEX_TRYLOCK_PI: - case FUTEX_WAIT_REQUEUE_PI: - case FUTEX_CMP_REQUEUE_PI: - if (!futex_cmpxchg_enabled) - return -ENOSYS; - } - - switch (cmd) { case FUTEX_WAIT: val3 = FUTEX_BITSET_MATCH_ANY; fallthrough; @@ -323,9 +307,6 @@ COMPAT_SYSCALL_DEFINE2(set_robust_list, struct compat_robust_list_head __user *, head, compat_size_t, len) { - if (!futex_cmpxchg_enabled) - return -ENOSYS; - if (unlikely(len != sizeof(*head))) return -EINVAL; @@ -342,9 +323,6 @@ COMPAT_SYSCALL_DEFINE3(get_robust_list, int, pid, unsigned long ret; struct task_struct *p; - if (!futex_cmpxchg_enabled) - return -ENOSYS; - rcu_read_lock(); ret = -ESRCH; |