preempt_mask.h defines all the preempt_count semantics and related symbols: preempt, softirq, hardirq, nmi, preempt active, need resched, etc... preempt.h defines the accessors and mutators of preempt_count. But there is a messy dependency game around those two header files: * preempt_mask.h includes preempt.h in order to access preempt_count() * preempt_mask.h defines all preempt_count semantic and symbols except PREEMPT_NEED_RESCHED that is needed by asm/preempt.h Thus we need to define it from preempt.h, right before including asm/preempt.h, instead of defining it to preempt_mask.h with the other preempt_count symbols. Therefore the preempt_count semantics happen to be spread out. * We plan to introduce preempt_active_[enter,exit]() to consolidate preempt_schedule*() code. But we'll need to access both preempt_count mutators (preempt_count_add()) and preempt_count symbols (PREEMPT_ACTIVE, PREEMPT_OFFSET). The usual place to define preempt operations is in preempt.h but then we'll need symbols in preempt_mask.h which already includes preempt.h. So we end up with a ressource circle dependency. Lets merge preempt_mask.h into preempt.h to solve these dependency issues. This way we gather semantic symbols and operation definition of preempt_count in a single file. This is a dumb copy-paste merge. Further merge re-arrangments are performed in a subsequent patch to ease review. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1431441711-29753-2-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>tirimbino
Frederic Weisbecker
10 years ago
committed by
Ingo Molnar
parent
a22ae71806
commit
92cf211874
@ -1,117 +0,0 @@ |
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#ifndef LINUX_PREEMPT_MASK_H |
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#define LINUX_PREEMPT_MASK_H |
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#include <linux/preempt.h> |
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/*
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* We put the hardirq and softirq counter into the preemption |
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* counter. The bitmask has the following meaning: |
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* |
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* - bits 0-7 are the preemption count (max preemption depth: 256) |
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* - bits 8-15 are the softirq count (max # of softirqs: 256) |
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* |
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* The hardirq count could in theory be the same as the number of |
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* interrupts in the system, but we run all interrupt handlers with |
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* interrupts disabled, so we cannot have nesting interrupts. Though |
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* there are a few palaeontologic drivers which reenable interrupts in |
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* the handler, so we need more than one bit here. |
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* |
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* PREEMPT_MASK: 0x000000ff |
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* SOFTIRQ_MASK: 0x0000ff00 |
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* HARDIRQ_MASK: 0x000f0000 |
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* NMI_MASK: 0x00100000 |
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* PREEMPT_ACTIVE: 0x00200000 |
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*/ |
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#define PREEMPT_BITS 8 |
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#define SOFTIRQ_BITS 8 |
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#define HARDIRQ_BITS 4 |
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#define NMI_BITS 1 |
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#define PREEMPT_SHIFT 0 |
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#define SOFTIRQ_SHIFT (PREEMPT_SHIFT + PREEMPT_BITS) |
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#define HARDIRQ_SHIFT (SOFTIRQ_SHIFT + SOFTIRQ_BITS) |
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#define NMI_SHIFT (HARDIRQ_SHIFT + HARDIRQ_BITS) |
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#define __IRQ_MASK(x) ((1UL << (x))-1) |
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#define PREEMPT_MASK (__IRQ_MASK(PREEMPT_BITS) << PREEMPT_SHIFT) |
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#define SOFTIRQ_MASK (__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT) |
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#define HARDIRQ_MASK (__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT) |
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#define NMI_MASK (__IRQ_MASK(NMI_BITS) << NMI_SHIFT) |
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#define PREEMPT_OFFSET (1UL << PREEMPT_SHIFT) |
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#define SOFTIRQ_OFFSET (1UL << SOFTIRQ_SHIFT) |
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#define HARDIRQ_OFFSET (1UL << HARDIRQ_SHIFT) |
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#define NMI_OFFSET (1UL << NMI_SHIFT) |
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#define SOFTIRQ_DISABLE_OFFSET (2 * SOFTIRQ_OFFSET) |
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#define PREEMPT_ACTIVE_BITS 1 |
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#define PREEMPT_ACTIVE_SHIFT (NMI_SHIFT + NMI_BITS) |
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#define PREEMPT_ACTIVE (__IRQ_MASK(PREEMPT_ACTIVE_BITS) << PREEMPT_ACTIVE_SHIFT) |
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#define hardirq_count() (preempt_count() & HARDIRQ_MASK) |
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#define softirq_count() (preempt_count() & SOFTIRQ_MASK) |
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#define irq_count() (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK \ |
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| NMI_MASK)) |
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/*
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* Are we doing bottom half or hardware interrupt processing? |
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* Are we in a softirq context? Interrupt context? |
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* in_softirq - Are we currently processing softirq or have bh disabled? |
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* in_serving_softirq - Are we currently processing softirq? |
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*/ |
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#define in_irq() (hardirq_count()) |
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#define in_softirq() (softirq_count()) |
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#define in_interrupt() (irq_count()) |
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#define in_serving_softirq() (softirq_count() & SOFTIRQ_OFFSET) |
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/*
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* Are we in NMI context? |
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*/ |
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#define in_nmi() (preempt_count() & NMI_MASK) |
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#if defined(CONFIG_PREEMPT_COUNT) |
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# define PREEMPT_CHECK_OFFSET 1 |
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#else |
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# define PREEMPT_CHECK_OFFSET 0 |
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#endif |
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/*
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* The preempt_count offset needed for things like: |
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* |
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* spin_lock_bh() |
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* |
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* Which need to disable both preemption (CONFIG_PREEMPT_COUNT) and |
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* softirqs, such that unlock sequences of: |
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* |
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* spin_unlock(); |
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* local_bh_enable(); |
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* |
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* Work as expected. |
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*/ |
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#define SOFTIRQ_LOCK_OFFSET (SOFTIRQ_DISABLE_OFFSET + PREEMPT_CHECK_OFFSET) |
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/*
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* Are we running in atomic context? WARNING: this macro cannot |
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* always detect atomic context; in particular, it cannot know about |
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* held spinlocks in non-preemptible kernels. Thus it should not be |
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* used in the general case to determine whether sleeping is possible. |
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* Do not use in_atomic() in driver code. |
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*/ |
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#define in_atomic() ((preempt_count() & ~PREEMPT_ACTIVE) != 0) |
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/*
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* Check whether we were atomic before we did preempt_disable(): |
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* (used by the scheduler, *after* releasing the kernel lock) |
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*/ |
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#define in_atomic_preempt_off() \ |
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((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_CHECK_OFFSET) |
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#ifdef CONFIG_PREEMPT_COUNT |
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# define preemptible() (preempt_count() == 0 && !irqs_disabled()) |
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#else |
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# define preemptible() 0 |
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#endif |
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#endif /* LINUX_PREEMPT_MASK_H */ |
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