diff options
| -rw-r--r-- | arch/i386/Kconfig | 4 | ||||
| -rw-r--r-- | arch/i386/kernel/semaphore.c | 162 | ||||
| -rw-r--r-- | arch/um/Kconfig_i386 | 4 | ||||
| -rw-r--r-- | arch/um/Kconfig_x86_64 | 4 | ||||
| -rw-r--r-- | arch/um/sys-x86_64/Makefile | 5 | ||||
| -rw-r--r-- | arch/x86_64/Kconfig | 4 | ||||
| -rw-r--r-- | arch/x86_64/kernel/Makefile | 2 | ||||
| -rw-r--r-- | lib/Makefile | 1 | ||||
| -rw-r--r-- | lib/semaphore-sleepers.c (renamed from arch/x86_64/kernel/semaphore.c) | 15 |
9 files changed, 26 insertions, 175 deletions
diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig index dcb0ad0..3b3b017 100644 --- a/arch/i386/Kconfig +++ b/arch/i386/Kconfig @@ -14,6 +14,10 @@ config X86 486, 586, Pentiums, and various instruction-set-compatible chips by AMD, Cyrix, and others. +config SEMAPHORE_SLEEPERS + bool + default y + config MMU bool default y diff --git a/arch/i386/kernel/semaphore.c b/arch/i386/kernel/semaphore.c index 469f496..7455ab6 100644 --- a/arch/i386/kernel/semaphore.c +++ b/arch/i386/kernel/semaphore.c @@ -13,171 +13,9 @@ * rw semaphores implemented November 1999 by Benjamin LaHaise <bcrl@kvack.org> */ #include <linux/config.h> -#include <linux/sched.h> -#include <linux/err.h> -#include <linux/init.h> #include <asm/semaphore.h> /* - * Semaphores are implemented using a two-way counter: - * The "count" variable is decremented for each process - * that tries to acquire the semaphore, while the "sleeping" - * variable is a count of such acquires. - * - * Notably, the inline "up()" and "down()" functions can - * efficiently test if they need to do any extra work (up - * needs to do something only if count was negative before - * the increment operation. - * - * "sleeping" and the contention routine ordering is protected - * by the spinlock in the semaphore's waitqueue head. - * - * Note that these functions are only called when there is - * contention on the lock, and as such all this is the - * "non-critical" part of the whole semaphore business. The - * critical part is the inline stuff in <asm/semaphore.h> - * where we want to avoid any extra jumps and calls. - */ - -/* - * Logic: - * - only on a boundary condition do we need to care. When we go - * from a negative count to a non-negative, we wake people up. - * - when we go from a non-negative count to a negative do we - * (a) synchronize with the "sleeper" count and (b) make sure - * that we're on the wakeup list before we synchronize so that - * we cannot lose wakeup events. - */ - -static fastcall void __attribute_used__ __up(struct semaphore *sem) -{ - wake_up(&sem->wait); -} - -static fastcall void __attribute_used__ __sched __down(struct semaphore * sem) -{ - struct task_struct *tsk = current; - DECLARE_WAITQUEUE(wait, tsk); - unsigned long flags; - - tsk->state = TASK_UNINTERRUPTIBLE; - spin_lock_irqsave(&sem->wait.lock, flags); - add_wait_queue_exclusive_locked(&sem->wait, &wait); - - sem->sleepers++; - for (;;) { - int sleepers = sem->sleepers; - - /* - * Add "everybody else" into it. They aren't - * playing, because we own the spinlock in - * the wait_queue_head. - */ - if (!atomic_add_negative(sleepers - 1, &sem->count)) { - sem->sleepers = 0; - break; - } - sem->sleepers = 1; /* us - see -1 above */ - spin_unlock_irqrestore(&sem->wait.lock, flags); - - schedule(); - - spin_lock_irqsave(&sem->wait.lock, flags); - tsk->state = TASK_UNINTERRUPTIBLE; - } - remove_wait_queue_locked(&sem->wait, &wait); - wake_up_locked(&sem->wait); - spin_unlock_irqrestore(&sem->wait.lock, flags); - tsk->state = TASK_RUNNING; -} - -static fastcall int __attribute_used__ __sched __down_interruptible(struct semaphore * sem) -{ - int retval = 0; - struct task_struct *tsk = current; - DECLARE_WAITQUEUE(wait, tsk); - unsigned long flags; - - tsk->state = TASK_INTERRUPTIBLE; - spin_lock_irqsave(&sem->wait.lock, flags); - add_wait_queue_exclusive_locked(&sem->wait, &wait); - - sem->sleepers++; - for (;;) { - int sleepers = sem->sleepers; - - /* - * With signals pending, this turns into - * the trylock failure case - we won't be - * sleeping, and we* can't get the lock as - * it has contention. Just correct the count - * and exit. - */ - if (signal_pending(current)) { - retval = -EINTR; - sem->sleepers = 0; - atomic_add(sleepers, &sem->count); - break; - } - - /* - * Add "everybody else" into it. They aren't - * playing, because we own the spinlock in - * wait_queue_head. The "-1" is because we're - * still hoping to get the semaphore. - */ - if (!atomic_add_negative(sleepers - 1, &sem->count)) { - sem->sleepers = 0; - break; - } - sem->sleepers = 1; /* us - see -1 above */ - spin_unlock_irqrestore(&sem->wait.lock, flags); - - schedule(); - - spin_lock_irqsave(&sem->wait.lock, flags); - tsk->state = TASK_INTERRUPTIBLE; - } - remove_wait_queue_locked(&sem->wait, &wait); - wake_up_locked(&sem->wait); - spin_unlock_irqrestore(&sem->wait.lock, flags); - - tsk->state = TASK_RUNNING; - return retval; -} - -/* - * Trylock failed - make sure we correct for - * having decremented the count. - * - * We could have done the trylock with a - * single "cmpxchg" without failure cases, - * but then it wouldn't work on a 386. - */ -static fastcall int __attribute_used__ __down_trylock(struct semaphore * sem) -{ - int sleepers; - unsigned long flags; - - spin_lock_irqsave(&sem->wait.lock, flags); - sleepers = sem->sleepers + 1; - sem->sleepers = 0; - - /* - * Add "everybody else" and us into it. They aren't - * playing, because we own the spinlock in the - * wait_queue_head. - */ - if (!atomic_add_negative(sleepers, &sem->count)) { - wake_up_locked(&sem->wait); - } - - spin_unlock_irqrestore(&sem->wait.lock, flags); - return 1; -} - - -/* * The semaphore operations have a special calling sequence that * allow us to do a simpler in-line version of them. These routines * need to convert that sequence back into the C sequence when diff --git a/arch/um/Kconfig_i386 b/arch/um/Kconfig_i386 index 27c18a8..8ad156a 100644 --- a/arch/um/Kconfig_i386 +++ b/arch/um/Kconfig_i386 @@ -6,6 +6,10 @@ config 64BIT bool default n +config SEMAPHORE_SLEEPERS + bool + default y + config TOP_ADDR hex default 0xc0000000 if !HOST_2G_2G diff --git a/arch/um/Kconfig_x86_64 b/arch/um/Kconfig_x86_64 index 735a047..6e5357c 100644 --- a/arch/um/Kconfig_x86_64 +++ b/arch/um/Kconfig_x86_64 @@ -6,6 +6,10 @@ config 64BIT bool default y +config SEMAPHORE_SLEEPERS + bool + default y + config TOP_ADDR hex default 0x80000000 diff --git a/arch/um/sys-x86_64/Makefile b/arch/um/sys-x86_64/Makefile index 7488206..736d3ed 100644 --- a/arch/um/sys-x86_64/Makefile +++ b/arch/um/sys-x86_64/Makefile @@ -6,7 +6,7 @@ #XXX: why into lib-y? lib-y = bitops.o bugs.o csum-partial.o delay.o fault.o mem.o memcpy.o \ - ptrace.o ptrace_user.o semaphore.o sigcontext.o signal.o stub.o \ + ptrace.o ptrace_user.o sigcontext.o signal.o stub.o \ stub_segv.o syscalls.o syscall_table.o sysrq.o thunk.o obj-y := ksyms.o @@ -15,7 +15,7 @@ obj-$(CONFIG_MODULES) += module.o um_module.o USER_OBJS := ptrace_user.o sigcontext.o SYMLINKS = bitops.c csum-copy.S csum-partial.c csum-wrappers.c memcpy.S \ - semaphore.c thunk.S module.c + thunk.S module.c include arch/um/scripts/Makefile.rules @@ -24,7 +24,6 @@ csum-copy.S-dir = lib csum-partial.c-dir = lib csum-wrappers.c-dir = lib memcpy.S-dir = lib -semaphore.c-dir = kernel thunk.S-dir = lib module.c-dir = kernel diff --git a/arch/x86_64/Kconfig b/arch/x86_64/Kconfig index 660a03a..75e52c5 100644 --- a/arch/x86_64/Kconfig +++ b/arch/x86_64/Kconfig @@ -24,6 +24,10 @@ config X86 bool default y +config SEMAPHORE_SLEEPERS + bool + default y + config MMU bool default y diff --git a/arch/x86_64/kernel/Makefile b/arch/x86_64/kernel/Makefile index 48f9e2c..427501a 100644 --- a/arch/x86_64/kernel/Makefile +++ b/arch/x86_64/kernel/Makefile @@ -4,7 +4,7 @@ extra-y := head.o head64.o init_task.o vmlinux.lds EXTRA_AFLAGS := -traditional -obj-y := process.o semaphore.o signal.o entry.o traps.o irq.o \ +obj-y := process.o signal.o entry.o traps.o irq.o \ ptrace.o time.o ioport.o ldt.o setup.o i8259.o sys_x86_64.o \ x8664_ksyms.o i387.o syscall.o vsyscall.o \ setup64.o bootflag.o e820.o reboot.o quirks.o diff --git a/lib/Makefile b/lib/Makefile index 52f8338..3e2bd0d 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -18,6 +18,7 @@ endif lib-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o +lib-$(CONFIG_SEMAPHORE_SLEEPERS) += semaphore-sleepers.o lib-$(CONFIG_GENERIC_FIND_NEXT_BIT) += find_next_bit.o obj-$(CONFIG_LOCK_KERNEL) += kernel_lock.o obj-$(CONFIG_DEBUG_PREEMPT) += smp_processor_id.o diff --git a/arch/x86_64/kernel/semaphore.c b/lib/semaphore-sleepers.c index 48f7c18..4d5f188 100644 --- a/arch/x86_64/kernel/semaphore.c +++ b/lib/semaphore-sleepers.c @@ -1,5 +1,5 @@ /* - * x86_64 semaphore implementation. + * i386 and x86-64 semaphore implementation. * * (C) Copyright 1999 Linus Torvalds * @@ -14,9 +14,8 @@ */ #include <linux/config.h> #include <linux/sched.h> +#include <linux/err.h> #include <linux/init.h> -#include <asm/errno.h> - #include <asm/semaphore.h> /* @@ -50,12 +49,12 @@ * we cannot lose wakeup events. */ -void __up(struct semaphore *sem) +fastcall void __up(struct semaphore *sem) { wake_up(&sem->wait); } -void __sched __down(struct semaphore * sem) +fastcall void __sched __down(struct semaphore * sem) { struct task_struct *tsk = current; DECLARE_WAITQUEUE(wait, tsk); @@ -92,7 +91,7 @@ void __sched __down(struct semaphore * sem) tsk->state = TASK_RUNNING; } -int __sched __down_interruptible(struct semaphore * sem) +fastcall int __sched __down_interruptible(struct semaphore * sem) { int retval = 0; struct task_struct *tsk = current; @@ -155,7 +154,7 @@ int __sched __down_interruptible(struct semaphore * sem) * single "cmpxchg" without failure cases, * but then it wouldn't work on a 386. */ -int __down_trylock(struct semaphore * sem) +fastcall int __down_trylock(struct semaphore * sem) { int sleepers; unsigned long flags; @@ -176,5 +175,3 @@ int __down_trylock(struct semaphore * sem) spin_unlock_irqrestore(&sem->wait.lock, flags); return 1; } - - |
