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author | 2015-08-04 12:17:53 -0700 | |
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committer | 2015-08-04 15:44:42 -0700 | |
commit | 9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch) | |
tree | 1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/arch/powerpc/lib/locks.c | |
parent | 98260f3884f4a202f9ca5eabed40b1354c489b29 (diff) |
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base.
It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and
the base is:
commit 0917f823c59692d751951bf5ea699a2d1e2f26a2
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Sat Jul 25 12:13:34 2015 +0200
Prepare v4.1.3-rt3
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
We lose all the git history this way and it's not good. We
should apply another opnfv project repo in future.
Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/arch/powerpc/lib/locks.c')
-rw-r--r-- | kernel/arch/powerpc/lib/locks.c | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/kernel/arch/powerpc/lib/locks.c b/kernel/arch/powerpc/lib/locks.c new file mode 100644 index 000000000..f7deebdf3 --- /dev/null +++ b/kernel/arch/powerpc/lib/locks.c @@ -0,0 +1,86 @@ +/* + * Spin and read/write lock operations. + * + * Copyright (C) 2001-2004 Paul Mackerras <paulus@au.ibm.com>, IBM + * Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM + * Copyright (C) 2002 Dave Engebretsen <engebret@us.ibm.com>, IBM + * Rework to support virtual processors + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#include <linux/kernel.h> +#include <linux/spinlock.h> +#include <linux/export.h> +#include <linux/stringify.h> +#include <linux/smp.h> + +/* waiting for a spinlock... */ +#if defined(CONFIG_PPC_SPLPAR) +#include <asm/hvcall.h> +#include <asm/smp.h> + +void __spin_yield(arch_spinlock_t *lock) +{ + unsigned int lock_value, holder_cpu, yield_count; + + lock_value = lock->slock; + if (lock_value == 0) + return; + holder_cpu = lock_value & 0xffff; + BUG_ON(holder_cpu >= NR_CPUS); + yield_count = be32_to_cpu(lppaca_of(holder_cpu).yield_count); + if ((yield_count & 1) == 0) + return; /* virtual cpu is currently running */ + rmb(); + if (lock->slock != lock_value) + return; /* something has changed */ + plpar_hcall_norets(H_CONFER, + get_hard_smp_processor_id(holder_cpu), yield_count); +} +EXPORT_SYMBOL_GPL(__spin_yield); + +/* + * Waiting for a read lock or a write lock on a rwlock... + * This turns out to be the same for read and write locks, since + * we only know the holder if it is write-locked. + */ +void __rw_yield(arch_rwlock_t *rw) +{ + int lock_value; + unsigned int holder_cpu, yield_count; + + lock_value = rw->lock; + if (lock_value >= 0) + return; /* no write lock at present */ + holder_cpu = lock_value & 0xffff; + BUG_ON(holder_cpu >= NR_CPUS); + yield_count = be32_to_cpu(lppaca_of(holder_cpu).yield_count); + if ((yield_count & 1) == 0) + return; /* virtual cpu is currently running */ + rmb(); + if (rw->lock != lock_value) + return; /* something has changed */ + plpar_hcall_norets(H_CONFER, + get_hard_smp_processor_id(holder_cpu), yield_count); +} +#endif + +void arch_spin_unlock_wait(arch_spinlock_t *lock) +{ + smp_mb(); + + while (lock->slock) { + HMT_low(); + if (SHARED_PROCESSOR) + __spin_yield(lock); + } + HMT_medium(); + + smp_mb(); +} + +EXPORT_SYMBOL(arch_spin_unlock_wait); |