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Merge tag 'xtensa-20190201' of git://github.com/jcmvbkbc/linux-xtensa
[mirror_ubuntu-disco-kernel.git] / arch / x86 / include / asm / spinlock.h
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_X86_SPINLOCK_H
3 #define _ASM_X86_SPINLOCK_H
4
5 #include <linux/jump_label.h>
6 #include <linux/atomic.h>
7 #include <asm/page.h>
8 #include <asm/processor.h>
9 #include <linux/compiler.h>
10 #include <asm/paravirt.h>
11 #include <asm/bitops.h>
12
13 /*
14 * Your basic SMP spinlocks, allowing only a single CPU anywhere
15 *
16 * Simple spin lock operations. There are two variants, one clears IRQ's
17 * on the local processor, one does not.
18 *
19 * These are fair FIFO ticket locks, which support up to 2^16 CPUs.
20 *
21 * (the type definitions are in asm/spinlock_types.h)
22 */
23
24 /* How long a lock should spin before we consider blocking */
25 #define SPIN_THRESHOLD (1 << 15)
26
27 #include <asm/qspinlock.h>
28
29 /*
30 * Read-write spinlocks, allowing multiple readers
31 * but only one writer.
32 *
33 * NOTE! it is quite common to have readers in interrupts
34 * but no interrupt writers. For those circumstances we
35 * can "mix" irq-safe locks - any writer needs to get a
36 * irq-safe write-lock, but readers can get non-irqsafe
37 * read-locks.
38 *
39 * On x86, we implement read-write locks using the generic qrwlock with
40 * x86 specific optimization.
41 */
42
43 #include <asm/qrwlock.h>
44
45 #endif /* _ASM_X86_SPINLOCK_H */